Supporting Information Dynamical Observation and Detailed ...
Supporting Information Dynamical Observation and Detailed Description of Catalysts under Strong Metal-Support Interaction Shuyi Zhang,1,2 Philipp N. Plessow,3,4, § Joshua J. Willis,4 Sheng Dai,1,2 Mingjie Xu,1,2 George W. Graham,1,2 Matteo Cargnello,4 Frank Abild-Pedersen,3 and Xiaoqing Pan1,5*
1
Department of Chemical Engineering and Materials Science, University of California -
Irvine, Irvine, California 92697, USA. 2
Department of Materials Science and Engineering, University of Michigan, Ann Arbor,
Michigan 48109, USA. 3
SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator
Laboratory, Menlo Park, California 94025, USA. 4
Department of Chemical Engineering and SUNCAT Center for Interface Science and
Catalysis, Stanford University, Stanford, California 94305, USA. 5
Department of Physics and Astronomy, University of California - Irvine, Irvine,
California 92697, USA. § Present
address: Institute of Catalysis Research and Technology (IKFT), Hermann-von-
Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany. *Corresponding Author, Email: [email protected]
Supplementary Materials: Materials and Methods Figures S1-S20 Table S1-S3
Supplementary Materials
Materials and Methods Synthesis of Pd/TiO2, Pt/TiO2, Au/TiO2 samples The supported catalyst systems were prepared by deposition of pre-formed metal nanocrystals onto commercial titania P25 (Sigma-Aldrich). Pd and Pt nanocrystals were synthesized according to reference 1, whereas Au nanocrystals followed reference 2. The conditions were: Pd nanocrystals A mixture of 0.25 mmol Pd(acac)2, 2.5 mmol oleylamine, 1.25 mmol trioctylphosphine, 1.25 mmol oleic acid, 6.6 mL 1-octadecene, 3.4 mL 1-tetradecene, reaction at 290 °C for 15 minutes. Pt nanocrystals A mixture of 0.25 mmol Pt(acac)2, 2.0 mmol oleylamine, 0.5 mmol trioctylphosphine, 4.0 mmol oleic acid, 10 mL of trioctylamine were reacted at 30 °C for 30 minutes. Au nanocrystals A mixture of 100 mg HAuCl4, 10 mL oleylamine (80-90%, Acros), 10 mL tetraline, were dissolved and reacted at room temperature with a solution of 0.5 mmol of tributylamine borane complex (Sigma-Aldrich) in 1 mL oleylamine and 1 mL tetraline. The purified nanocrystals dissolved in hexanes at appropriate concentrations were added to a stirred solution of titania P25 in toluene (40 mL) in order to obtain a final loading of 0.5 wt. % in metal. The samples were left stirring for 30 minutes. Powders were collected by centrifugation, dried overnight and the organic ligands removed following a fast thermal treatment in a furnace at 700 °C for 30 seconds.
Characterization techniques In situ TEM was conducted on a JEOL 3100-R05 microscope with double Cs-correctors operated at 300 kV using the Protochips Atmosphere system as described before 3, and EELS data was acquired with Gatan #965 Quantum Imaging Filter (GIF) for electron energy loss spectroscopy and imaging. The purity of the gases used in the in situ experiment was 99.9995%. All reported temperatures are based on the Protochips calibration. DFT calculation DFT-calculations have been carried out with Quantum Espresso 4 using ultrasoft pseudopotentials5 and Fermi-Dirac smearing with kBT = 0.1 eV, except for gas-phase molecules, where integer occupation numbers have been enforced. The energy cut-off for the plane wave expansion of wave function (density) was 500 eV (5000 eV). We have used H2 and H2O as reference gas-phase molecules and the O2-reference was obtained using its experimental binding energy corrected by the zero-point energy: E(O2) = E(H2O) – E(H2) + 2.75 eV. Γ-centered k-point sampling was used in all cases. Generally we employed a kpoint-density roughly corresponding to (12×12×1) per (1×1)-Pd-fcc(111) surface unit cell. This has been found to give sufficiently converged energies (see below). Slabs were separated by about 16 Å and the dipole correction has additionally been used to reduce the artificial interaction between slabs 6. All presented number have been obtained using non spin-polarized calculations. We have thoroughly tested many structures for spin-polarized solutions. However, despite using strongly magnetic guesses for the initial wave function, all converged solutions were non-magnetic. This is in agreement with calculations reported for TiOx overlayers
7, 8
. To avoid convergence issues with surface energies, they were
calculated using the ’linear-fit’ method, e.g. the bulk reference energy was obtained by linear regression of the total slab-energies with respect to the number of layers. The free energy of solids and surfaces is approximated by their electronic energies. Free energies of gas phase molecules were obtained using the usual corrections from statistical thermodynamics for translation, (harmonic) oscillation and (rigid) rotation.
Estimate of experimental condition Double layer: The cell was purged with pure N2 (purity 99.9995%) and pumped to 0.1 Torr twice before it was filled with 760 Torr 5%H2/Ar (purity 99.9995%). Assuming air at saturated water vapor, ~17 Torr at 20 °C, can go into the cell during assembling and dissembling, the calculated water vapor concentration upon pump/purging would be 0.3×10-6 bar. On the other hand, considering the impurity of the forming gas, the residual H2O and O2 will result in a concentration of 0.6 ppm H2O, corresponding to 0.6×10-6 bar. Therefore, we assume that the initial water pressure is 10-6 bar or lower and will use 10-6 bar here as the upper limit. The experimental equilibrium constant (K in bar-0.5) for the reaction 0.5 O2 + H2 H2O is at T = 700 K log10(K) = 15.582 and log10(K) = 13.287 at T = 800 K. With K = p(H2O) / ( p(H2) * p(O2)0.5) It follows that p(O2) ~ 10-41 bar at T = 700 K and p(O2) ~ 10-36 bar at T = 800 K. Using the experimental reaction energy and employing the usual corrections from statistical thermodynamics for translation, (harmonic) oscillation, (rigid) rotation, we obtain for T = 773.15 K, p(H2)=0.05 bar, p(H2O)= 10-6 bar, µO = -3.7 eV. The experimental condition would be located at somewhere smaller than -3.7 eV. Single layer: The cell was filled with a mixture 15 Torr O2 and 745 Torr 5% H2/Ar. If equilibrium is reached, p(H2)=0.01 bar and p(H2O)=0.04 bar, using the same equation shown in the double layer formation condition, we obtain µO ~ -2.8 eV. No layer The cell was filled with a mixture of 43 Torr O2 and 720 Torr 5% H2/Ar. If equilibrium is reached, p(O2) =0.032 bar and p(H2O)= 0.048 bar, and the corresponding chemical potential would be µO ~ -0.9 eV.
Figure S1
Ex situ BF STEM images showing that the surfaces of the Pd particles are initially (i.e., before conducting the in-situ experiments) clean at room temperature.
Figure S2
ABF STEM images taken in situ showing that most of the Pd particles in Pd/TiO2 are covered by a thin amorphous layer at 300 °C under H2 (5 vol. %)/Ar at 1 atm.
Figure S3
ABF STEM images showing that no change occurred when Pd/Al2O3 was heated under H2 (5 vol. %)/Ar at 1 atm total pressure at 500 °C. The shape of the Pd nanoparticle is a truncated octahedron with smooth truncation between the two major facets, (111) and (100).
Figure S4-S6 Beam effect considerations We are aware that beam effects could possibly create artifacts. All the images were taken with a significantly reduced probe current, ~7 pA, while the probe current for normal STEM imaging is between 50-100 pA 9, 10. To minimize beam effect, Chi et al. used 20 pA probe current to study in-situ surface faceting of metal particles of similar size 11. Our probe size is estimated to be about 0.8 Å, which is typical for state-of-the-art aberration corrected STEM (1.3 Å after the membrane), before crossing the membrane of the cell. Our current density is 4 pA/Å2 , about 1 to 2 orders of magnitude lower than typical values
12
. Our
electron dose could go up to 104 e/Å2 to acquire the highest quality image, but we immediately reduced it to less than 100 e/Å2 after image acquisition. One direct way to identify the occurrence of electron beam damage is to record images of the same area before and after irradiation and compare the contrast under the same imaging conditions. No change was found when the samples were illuminated with the same conditions for prolonged time, as shown in the figures below. At a relatively higher oxygen potential (H2 (4.7 vol. %)/O2 (5.7 vol. %)/Ar, µO~ -0.9eV), the surfaces of Pd particles stayed clean at 500 °C during 20 min observation, as shown in Figure S4. At lower oxygen potential (H2 (5 vol. %)/Ar, µO< -3.7 eV), an amorphous layer starts to migrate onto the particles at temperatures around 250 °C. During 15 min observation at 250 °C under H2 (5 vol. %)/Ar at 1 atm, no change was observed, as shown in Figure S5. Finally, when the temperature was raised to 500 °C under the same gas atmosphere (H2 (5 vol. %)/Ar at 1 atm), two crystalline layers were instantaneously formed, and they were observed to be very stable under the beam illumination for 90 min, as shown in Figure S6. Furthermore, as shown in Figures S3 and S10, no over layer formed when the support material was changed to Al2O3, or the metal was changed to Au, suggesting the formation of the over layer is material dependent but not electron beam dependent. Thus, we believe that the electron beam didn’t play a significant role in any of the phenomena reported in this paper.
Figure S4 ABF images showing that no amorphous layer migrate onto the particle under H2 (4.7 vol. %)/O2 (5.7 vol. %)/Ar at 500 °C during 20mins electron beam illumination.
Figure S5 ABF images showing that an amorphous layer start to form on the surface of the particle at 250 °C under H2 (5 vol. %)/Ar at 1 atm and no changes have been observed in the images taken at varied time.
Figure S6 Pairs of HAADF and ABF images showing that no structural damage can be discerned in the images taken at varied time up to 90 mins of illumination at 500 °C under H2 (5 vol. %)/Ar at 1 atm.
Figure S7
ABF images showing more examples of double TiOx layer formed under H2 (5 vol. %)/Ar at 1 atm at 500 °C (A,B) and single layer formed under H2 (4.9 vol. %)/O2 (2 vol. %)/Ar at 1 atm at 500 °C (C,D).
Figure S8
Original ABF images (A-C) and HAADF image (A’-C’) of the false color images shown in Figure 2B-D.
Figure S9
ABF images showing the formation of TiOx double layer on Pt particles in Pt/TiO2 under H2 (5 vol. %)/Ar at 1 atm.
Figure S10
ABF images showing that the surface of Au particles in Au/TiO2 are clean after 1 h heating under H2 (5 vol. %)/Ar at 1 atm at 500 °C.
DFT calculation result of Pt and Au We have computed the thermodynamic stability of k-phase single and double layers of TiOx in the (1×1)/(2×2) super cell on Pt and Au, as well as Pd. Generally, both overlayers are stable on Pd and Pt and unstable on Au. Table S1 Comparison of the stability of the k-phase single and double layers of TiOx on the (111) facets of different metals on at μO = -3.7 eV. Free energies of formation are given in eV.
single
double
Au
0.04
0.18
Pd
-0.23
-0.19
Pt
-0.32
-0.40
Figure S11
Stability of k-phase single and double-layer TiOx structures supported on (111) Au, Pd and Pt. The number of layers is given in parentheses.
Figure S12 Wulff construction 𝛾100 𝛾111
ℎ
𝑁
= ℎ100 = √3 𝑁𝑇 111
𝑝
γ is the surface energy of specific plane and h is the distance from the center of the supported NP. The diameter of the NP is given by(𝑎0 /√2) ∙ 𝑁𝑃 . So Np is the number of atomic rows along diameter and NT is the number of atomic layers from the top to the center as shown below. The tilting of the particle doesn’t affect the counting of NP and NT.
Schematic showing NP and NT
Figure S13
Dynamic process showing the disorder to order transition accompanied by the faceting of the particle under 760 Torr 5%H2/N2 (A) 300 °C (B) 400 °C 2 min (C) 400 °C 15 min (D) 400 °C 47 min (E) 500 °C.
Figure S14
ABF images showing that after ex situ reduction conducted in a tube furnace for 1 hr at 500 °C under H2 (5 vol. %)/Ar, Pd particles in Pd/TiO2 are covered by a thin amorphous layer, which is in accordance with most of the literature reports. No crystalline layer can be discerned.
More Details of the DFT calculations Convergence Tests We have tested the accuracy resulting from different k-point sampling and plane wave cutoffs for mono- and double-layer of the k-phase for the smallest supercell, 1×1/2×2. As shown in Table S2, we expect the chosen plane-wave cutoff (500 eV) to give energies that are accurate to 0.01 eV per Ti atom. A similar accuracy is reached with a 8x8x1 kpoint sampling. Using a sampling of 6×6×1 results in an error of about 0.03 eV, which is still acceptable. Table S2 Formation energy (eV) of double and monolayer in a 1x1/2x2 supercell as a function of k-point sampling and wave function plane-wave cutoff. monolayer
monolayer
double-layer
double-layer
Eform / n(Ti)
Eform / n(Ti)
Eform / n(Ti)
Eform / n(Ti)
Cutoff
k-points
1000 eV
4x4x1
1.317
0.027
3.117
0.024
1000 eV
6x6x1
1.261
-0.029
3.060
-0.033
1000 eV
8x8x1
1.302
0.013
3.106
0.013
1000 eV
10x10x1
1.296
0.007
3.097
0.004
1000 eV
12x12x1
1.289 := 0
400 eV
8x8x1
1.288
-0.014
3.076
-0.031
500 eV
8x8x1
1.306
0.004
3.098
-0.008
600 eV
8x8x1
1.307
0.005
3.111
0.004
800 eV
8x8x1
1.302
0.000
3.107
0.001
1000 eV
8x8x1
1.302 := 0
3.093 :=0
3.106 :=0
Lattice mismatch Before turning to minimizing the lattice mismatch, it is important to realize that it is to some extent depending on temperature and partial pressures. As µO determines the stability of an overlayer, the same overlayer in different supercells with different deficiency of oxygen per unit cell will lead to different slopes in the plot of free energy of formation versus µO. This is shown below for two stable supercells of the single layer k-phase structure. The super cell with higher coverage of the k-phase, (1×1)/(2×2), is more oxygendefiant per surface area. Consequently the slope is larger and this structure is more stable at lower µO, while the other is more stable at µO. The crossover occurs in the relevant region of µO. Since the difference is not large, we pick the less dense unit cell, because this is the supercell in which the double layer is most stable. Figure S15
Stability of Pd(111)-supported k-phase single layers with different coverages. The lattice constant of the overlayer has been varied by creating various supercells (see Table S3). The obtained free energy curve as a function of lattice mismatch is depicted at µO = -3.7 eV in Figures SX. This is the approximate crossover between single and double-layer. As mentioned above, two super-cells have similar stability for the single
layer, while for the double layer it is clear, which super cell is most stable. The reason for the stability of the single layer in this small unit cell is probably that both Ti-atoms are three-fold coordinated by Pd. For all other supercells this is not the case. This unit cell is therefore likely an anomaly in the generally well-behaved potential energy curve. For the double layer, this effect is expected to be weaker as the compression acts on both layers, while the effect of interface bonding affects only one layer. For the double layer, a continuous curve is obtained, both for single and double layer. Since the overlayer generally has different orientations with respect to the support, this means that the influence of the orientation is likely smaller. At higher lattice-constants, where the overlayer becomes unstable, two different orientations leading to the same lattice constant, (√3×√3)-R30°/(4×4) and (3×3)/(4√3×4√3)-R30°, give a very similar formation energy.
Table S3 Data used to determine the minimum lattice mismatch. The k-point density in one dimension is given by the number of Pd atoms in one direction times the number of k-points in this direction. Lengths supercell /Å
k-phase- k-point 1D-k-point 2 Pd layers 4 Pd layers layers density grid G / eV G / eV
(√3×√3)-R30°/ 5.81
double
2x2x1
7.2
-0.232
-0.241
single
2x2x1
7.2
-0.211
-0.228
double
3x3x1
10.8
-0.227
single
3x3x1
10.8
-0.217
double
4x4x1
14.4
-0.228
-0.226
single
4x4x1
14.4
-0.215
-0.216
double
1x1x1
7.0
-0.187
single
1x1x1
7.0
-0.194
double
2x2x1
14.0
-0.216
(√13×√13)-R14°
(2√3×2√3)-R30°/(7×7)
5.64
(1×1)/(2×2)
(4×4)/(5√3×5√3)-R30°
(√3×√3)-R30°/(4×4)
(3×3)/(4√3×4√3)-R30°
5.58
6.04
6.45
6.45
single
2x2x1
14.0
-0.205
double
6x6x1
12.0
-0.197
-0.189
single
6x6x1
12.0
-0.192
-0.225
double
1x1x1
8.7
-0.187
single
1x1x1
8.7
-0.200
double
2x2x1
8.0
0.094
single
2x2x1
8.0
-0.028
single
1x1x1
6.9
-0.053
Figure S16
Figure SX Formation free energies per Pd-surface atom plotted agains the k-phase lattice constant. Insets shows a top view of k-phase single layer structures in various lattice constants.
Overview Pd(111) supported structures As described in the main text, the most stable obtained structures are the single and double layer of the k-phase. Other likely alternatives, that would also be in agreement with the experimental cross section (see below), are rocksalt(111)-derived structures. Various of the more complex reported TiOx structures are derived from a layer of closed-packed Ti atoms with threefold coordinated oxygen atoms in the fcc-sites. We have modeled the nondefected TiO-overlayer in a (√3×√3)-R30°-TiO/(2×2)-Pd(111) cell. At relatively high O, the TiO-layer is found to be less stable than the Ti2O3 mono-layer, while its stability is competitive with the double layer of Ti2O3 at lower O. Within the accuracy of our calculations this does certainly not rule out the existence of the double layer of Ti2O3, but the high density and high oxygen deficiency of the TiO-monolayer will certainly make it the most stable structure at sufficiently low O. Figure S17
Stability of Pd(111)-supported structures. Structural representations are shown as insets.
Orientation and comparison to experimental cross-section All experimental images show rows of atoms along the view axis. It is therefore likely that this true for all three symmetry-equivalent axis of the support, although images for each particle were only taken along one axis. This means that each layer of the overlayer should have a hexagonal symmetry. The entire overlayer does not necessarily have a hexagonal symmetry, since the rotational symmetry axis can be centered at different positions, as is the case for the double layer. Being restricted to periodic boundary conditions, various lattice mismatches can only be explored by also introducing different orientations of overlayer with respect to support, as done above. The orientation of the overlayer seems to be less important energetically, although we cannot check that explicitly in most cases. In terms of the actual orientation, it is highly likely that the support and overlayer are aligned along a symmetric axes in the most stable system, although the energetic stabilization may be small per unit cell. There are two highly symmetric orientations, one would be to align the lattice vectors of the minimal unit cells. The other one would be to rotate either overlayer or support by 30°. Technically this can be realized by generating a (√3×√3)-R30°unit cell of either support or overlayer and aligning it with the corresponding other minimal unit cell. The first orientation is in disagreement with the experimentally observed cross section that shows rows of atoms along the view axis, the second is in agreement. We illustrate this for the supercell (2√3×2√3)-R30°/(7×7), which is not the most stable unit cell, probably because the overlayers are stretched too much.
Figure S18
Cross section of super cell in which the orientation of k-phase and Pd(111) agrees with the experimental cross section.
Testing overlayers that include hydrogen We have studied hydrogenated k-phase single- and double layers with one, two or three H atoms per unit cell, where hydrogen binds to the bridging oxygens, forming hydroxyl groups. This corresponds to coverages of 1/3, 2/3 and 1 in terms of the available oxygen atoms. Calculations have been carried out in the (1×1)/(2×2) supercells and since hydrogen adsorption was generally found to be unstable, we did not investigate other supercells. The Figure below shows the stability of the hydrogenated single and double layers. We have assumed a constant hydrogen partial pressure of 0.05 bar. This way the hydrogenated phases have the same slope of formation free energies with respect to the chemical potential of oxygen. The unit cell of the hydrogenated single layers is included for illustration. All hydrogenated overlayers are instable with respect to the bare overlayers and become increasingly unstable with higher H-coverage.
Figure S19
Stability of hydrogenated single and double layers. Structural models are shown in an inset.
Overlayers on Pd(100) Forming supercells with low lattice mismatch is more challenging since the minimal unit cell of Pd(100) is cubic and that of the k-phase is hexagonal. We have therefore generated a rectangular k-phase unit cell, which fits best onto a (2×5)-Pd(100) supercell. In the same way, we have generated a supercell with the hexagonal TiO structure on Pd(100). Additionally, we found a cubic structure that it is stable at low O. This cubic structure is the analagon to rocksalt(111)/Pd(111) for Pd(100): It is a continuation of the fcc(100) facet with one layer of Ti and one layer of oxygen.
Figure S20
Stability of Pd(100)-supported layers. Structural models are shown in an insets.
Cartesian coordinates of the most relevant structures Structures of the overlayers discussed in the main article are given in the .cif format below. 100-Monolayer data_image0 _cell_length_a
5.58418
_cell_length_b
11.1684
_cell_length_c
24.6238
_cell_angle_alpha 90 _cell_angle_beta
90
_cell_angle_gamma
loop_ _atom_site_label
90
_atom_site_occupancy _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_thermal_displace_type _atom_site_B_iso_or_equiv _atom_site_type_symbol Pd1
1.0000 0.25000 0.12500 0.32489 Biso 1.000 Pd
Pd2
1.0000 0.00000 0.00000 0.40507 Biso 1.000 Pd
Pd3
1.0000 0.25104 0.12605 0.48521 Biso 1.000 Pd
Pd4
1.0000 0.00101 0.00135 0.56587 Biso 1.000 Pd
Pd5
1.0000 0.25000 0.37500 0.32489 Biso 1.000 Pd
Pd6
1.0000 0.00000 0.25000 0.40507 Biso 1.000 Pd
Pd7
1.0000 0.25040 0.37606 0.48578 Biso 1.000 Pd
Pd8
1.0000 0.00356 0.25214 0.56577 Biso 1.000 Pd
Pd9
1.0000 0.25000 0.62500 0.32489 Biso 1.000 Pd
Pd10
1.0000 0.00000 0.50000 0.40507 Biso 1.000 Pd
Pd11
1.0000 0.25092 0.62514 0.48557 Biso 1.000 Pd
Pd12
1.0000 0.99394 0.50444 0.56678 Biso 1.000 Pd
Pd13
1.0000 0.25000 0.87500 0.32489 Biso 1.000 Pd
Pd14
1.0000 0.00000 0.75000 0.40507 Biso 1.000 Pd
Pd15
1.0000 0.25128 0.87590 0.48562 Biso 1.000 Pd
Pd16
1.0000 0.00889 0.75195 0.56676 Biso 1.000 Pd
Pd17
1.0000 0.75000 0.12500 0.32489 Biso 1.000 Pd
Pd18
1.0000 0.50000 0.00000 0.40507 Biso 1.000 Pd
Pd19
1.0000 0.75087 0.12509 0.48555 Biso 1.000 Pd
Pd20
1.0000 0.49398 0.00446 0.56684 Biso 1.000 Pd
Pd21
1.0000 0.75000 0.37500 0.32489 Biso 1.000 Pd
Pd22
1.0000 0.50000 0.25000 0.40507 Biso 1.000 Pd
Pd23
1.0000 0.75123 0.37589 0.48560 Biso 1.000 Pd
Pd24
1.0000 0.50869 0.25186 0.56665 Biso 1.000 Pd
Pd25
1.0000 0.75000 0.62500 0.32489 Biso 1.000 Pd
Pd26
1.0000 0.50000 0.50000 0.40507 Biso 1.000 Pd
Pd27
1.0000 0.75108 0.62613 0.48523 Biso 1.000 Pd
Pd28
1.0000 0.50105 0.50131 0.56585 Biso 1.000 Pd
Pd29
1.0000 0.75000 0.87500 0.32489 Biso 1.000 Pd
Pd30
1.0000 0.50000 0.75000 0.40507 Biso 1.000 Pd
Pd31
1.0000 0.75042 0.87605 0.48581 Biso 1.000 Pd
Pd32
1.0000 0.50354 0.75217 0.56587 Biso 1.000 Pd
Ti1
1.0000 0.27223 0.07976 0.65715 Biso 1.000 Ti
Ti2
1.0000 0.74963 0.26602 0.65812 Biso 1.000 Ti
O1
1.0000 0.01818 0.17713 0.67268 Biso 1.000 O
Ti3
1.0000 0.77209 0.57909 0.65709 Biso 1.000 Ti
O2
1.0000 0.75339 0.42311 0.68119 Biso 1.000 O
O3
1.0000 0.51661 0.16838 0.68488 Biso 1.000 O
Ti4
1.0000 0.24969 0.76563 0.65828 Biso 1.000 Ti
O4
1.0000 0.25329 0.92348 0.68102 Biso 1.000 O
O5
1.0000 0.51761 0.67620 0.67278 Biso 1.000 O
O6
1.0000 0.01809 0.66651 0.68478 Biso 1.000 O
Monolayer, (√3×√3)-R30°/(√13×√13)-R14° data_image0 _cell_length_a
5.58418
_cell_length_b
5.58418
_cell_length_c
25.8005
_cell_angle_alpha 90 _cell_angle_beta
90
_cell_angle_gamma
120
loop_ _atom_site_label _atom_site_occupancy _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_thermal_displace_type _atom_site_B_iso_or_equiv _atom_site_type_symbol Pd1
1.0000 0.00000 0.00000 0.31007 Biso 1.000 Pd
Pd2
1.0000 0.33333 0.16667 0.39843 Biso 1.000 Pd
Pd3
1.0000 0.16517 0.33348 0.48756 Biso 1.000 Pd
Pd4
1.0000 0.99998 0.00003 0.57765 Biso 1.000 Pd
Pd5
1.0000 0.00000 0.50000 0.31007 Biso 1.000 Pd
Pd6
1.0000 0.33333 0.66667 0.39843 Biso 1.000 Pd
Pd7
1.0000 0.16825 0.83483 0.48757 Biso 1.000 Pd
Pd8
1.0000 0.00011 0.50645 0.57894 Biso 1.000 Pd
Pd9
1.0000 0.50000 0.00000 0.31007 Biso 1.000 Pd
Pd10
1.0000 0.83333 0.16667 0.39843 Biso 1.000 Pd
Pd11
1.0000 0.66665 0.33336 0.48746 Biso 1.000 Pd
Pd12
1.0000 0.50624 0.99988 0.57894 Biso 1.000 Pd
Pd13
1.0000 0.50000 0.50000 0.31007 Biso 1.000 Pd
Pd14
1.0000 0.83333 0.66667 0.39843 Biso 1.000 Pd
Pd15
1.0000 0.66653 0.83176 0.48756 Biso 1.000 Pd
Pd16
1.0000 0.49354 0.49376 0.57894 Biso 1.000 Pd
Ti1
1.0000 0.66635 0.33328 0.66061 Biso 1.000 Ti
Ti2
1.0000 0.99968 0.00009 0.66775 Biso 1.000 Ti
Ti3
1.0000 0.33316 0.66678 0.66096 Biso 1.000 Ti
O1
1.0000 0.66636 0.66649 0.68965 Biso 1.000 O
O2
1.0000 0.99968 0.33356 0.68965 Biso 1.000 O
O3
1.0000 0.33316 0.00013 0.68965 Biso 1.000 O
Doublelayer, (√3×√3)-R30°/(√13×√13)-R14°
data_image0 _cell_length_a
10.067
_cell_length_b
10.067
_cell_length_c
28.5747
_cell_angle_alpha 90 _cell_angle_beta
90
_cell_angle_gamma
60
_symmetry_space_group_name_H-M _symmetry_int_tables_number
P1
1
loop_ _symmetry_equiv_pos_as_xyz 'x, y, z'
loop_ _atom_site_label _atom_site_occupancy _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_thermal_displace_type _atom_site_B_iso_or_equiv _atom_site_type_symbol Pd1
1.0000 0.93480 0.33972 0.27997 Biso 1.000 Pd
Pd2
1.0000 0.85788 0.64741 0.27997 Biso 1.000 Pd
Pd3
1.0000 0.16557 0.41664 0.27997 Biso 1.000 Pd
Pd4
1.0000 0.78095 0.95510 0.27997 Biso 1.000 Pd
Pd5
1.0000 0.08865 0.72433 0.27997 Biso 1.000 Pd
Pd6
1.0000 0.39634 0.49356 0.27997 Biso 1.000 Pd
Pd7
1.0000 0.01172 0.03203 0.27997 Biso 1.000 Pd
Pd8
1.0000 0.31941 0.80126 0.27997 Biso 1.000 Pd
Pd9
1.0000 0.62711 0.57049 0.27997 Biso 1.000 Pd
Pd10
1.0000 0.55018 0.87818 0.27997 Biso 1.000 Pd
Pd11
1.0000 0.80659 0.51921 0.35975 Biso 1.000 Pd
Pd12
1.0000 0.11429 0.28844 0.35975 Biso 1.000 Pd
Pd13
1.0000 0.72967 0.82690 0.35975 Biso 1.000 Pd
Pd14
1.0000 0.03736 0.59613 0.35975 Biso 1.000 Pd
Pd15
1.0000 0.34506 0.36536 0.35975 Biso 1.000 Pd
Pd16
1.0000 0.96044 0.90382 0.35975 Biso 1.000 Pd
Pd17
1.0000 0.26813 0.67305 0.35975 Biso 1.000 Pd
Pd18
1.0000 0.57582 0.44228 0.35975 Biso 1.000 Pd
Pd19
1.0000 0.19121 0.98074 0.35975 Biso 1.000 Pd
Pd20
1.0000 0.49890 0.74997 0.35975 Biso 1.000 Pd
Pd21
1.0000 0.67875 0.69758 0.43913 Biso 1.000 Pd
Pd22
1.0000 0.98624 0.46960 0.43972 Biso 1.000 Pd
Pd23
1.0000 0.59836 0.00651 0.43961 Biso 1.000 Pd
Pd24
1.0000 0.90860 0.77556 0.43998 Biso 1.000 Pd
Pd25
1.0000 0.21647 0.54572 0.43959 Biso 1.000 Pd
Pd26
1.0000 0.13895 0.85406 0.44110 Biso 1.000 Pd
Pd27
1.0000 0.44520 0.62238 0.43987 Biso 1.000 Pd
Pd28
1.0000 0.36829 0.92918 0.44031 Biso 1.000 Pd
Pd29
1.0000 0.24249 0.10895 0.27997 Biso 1.000 Pd
Pd30
1.0000 0.47326 0.18587 0.27997 Biso 1.000 Pd
Pd31
1.0000 0.70403 0.26279 0.27997 Biso 1.000 Pd
Pd32
1.0000 0.42198 0.05767 0.35975 Biso 1.000 Pd
Pd33
1.0000 0.65275 0.13459 0.35975 Biso 1.000 Pd
Pd34
1.0000 0.88352 0.21151 0.35975 Biso 1.000 Pd
Pd35
1.0000 0.06349 0.15979 0.43977 Biso 1.000 Pd
Pd36
1.0000 0.29314 0.23698 0.44105 Biso 1.000 Pd
Pd37
1.0000 0.52398 0.31161 0.44082 Biso 1.000 Pd
Pd38
1.0000 0.83128 0.08390 0.44033 Biso 1.000 Pd
Pd39
1.0000 0.75465 0.38877 0.43909 Biso 1.000 Pd
Pd40
1.0000 0.93481 0.34191 0.51826 Biso 1.000 Pd
Pd41
1.0000 0.85490 0.64958 0.52131 Biso 1.000 Pd
Pd42
1.0000 0.16171 0.42405 0.52230 Biso 1.000 Pd
Pd43
1.0000 0.77523 0.95540 0.51986 Biso 1.000 Pd
Pd44
1.0000 0.08307 0.73108 0.52252 Biso 1.000 Pd
Pd45
1.0000 0.39694 0.48932 0.52086 Biso 1.000 Pd
Pd46
1.0000 0.00688 0.03578 0.52404 Biso 1.000 Pd
Pd47
1.0000 0.31743 0.79843 0.52448 Biso 1.000 Pd
Pd48
1.0000 0.62819 0.56541 0.51812 Biso 1.000 Pd
Pd49
1.0000 0.54612 0.87187 0.51988 Biso 1.000 Pd
Pd50
1.0000 0.23981 0.10778 0.52321 Biso 1.000 Pd
Pd51
1.0000 0.47249 0.18111 0.52520 Biso 1.000 Pd
Pd52
1.0000 0.70379 0.26031 0.52330 Biso 1.000 Pd
O1
1.0000 0.07255 0.74559 0.63135 Biso 1.000 O
Ti1
1.0000 0.58774 0.95668 0.59390 Biso 1.000 Ti
O2
1.0000 0.40339 0.08856 0.63124 Biso 1.000 O
O3
1.0000 0.75169 0.94820 0.62433 Biso 1.000 O
Ti2
1.0000 0.91760 0.26264 0.59430 Biso 1.000 Ti
O4
1.0000 0.07140 0.27834 0.62348 Biso 1.000 O
O5
1.0000 0.94980 0.07876 0.63129 Biso 1.000 O
O6
1.0000 0.73073 0.42214 0.62745 Biso 1.000 O
Ti3
1.0000 0.23787 0.26500 0.59247 Biso 1.000 Ti
Ti4
1.0000 0.25852 0.59148 0.59290 Biso 1.000 Ti
O7
1.0000 0.40360 0.62300 0.62322 Biso 1.000 O
O8
1.0000 0.27933 0.41487 0.63002 Biso 1.000 O
O9
1.0000 0.61204 0.76328 0.62915 Biso 1.000 O
Ti5
1.0000 0.57011 0.61773 0.59698 Biso 1.000 Ti
Ti6
1.0000 0.92448 0.92516 0.59424 Biso 1.000 Ti
O10
1.0000 0.20252 0.57891 0.71891 Biso 1.000 O
Ti7
1.0000 0.67460 0.73800 0.69247 Biso 1.000 Ti
O11
1.0000 0.53509 0.91588 0.71929 Biso 1.000 O
O12
1.0000 0.87073 0.69354 0.70098 Biso 1.000 O
Ti8
1.0000 0.00784 0.06684 0.69428 Biso 1.000 Ti
O13
1.0000 0.20296 0.02828 0.70119 Biso 1.000 O
O14
1.0000 0.98764 0.91351 0.72003 Biso 1.000 O
O15
1.0000 0.86464 0.25162 0.71738 Biso 1.000 O
Ti9
1.0000 0.35903 0.06735 0.69382 Biso 1.000 Ti
Ti10
1.0000 0.34077 0.39844 0.69279 Biso 1.000 Ti
O16
1.0000 0.53646 0.36022 0.69861 Biso 1.000 O
O17
1.0000 0.31859 0.24742 0.71956 Biso 1.000 O
O18
1.0000 0.64719 0.58542 0.71549 Biso 1.000 O
Ti11
1.0000 0.69016 0.40226 0.69129 Biso 1.000 Ti
Ti12
1.0000 0.02722 0.73283 0.69417 Biso 1.000 Ti
111: TiO-rocksalt(111) data_image0 _cell_length_a
10.067
_cell_length_b
10.067
_cell_length_c
25.9455
_cell_angle_alpha 90 _cell_angle_beta
90
_cell_angle_gamma
60
_symmetry_space_group_name_H-M _symmetry_int_tables_number
P1
1
loop_ _symmetry_equiv_pos_as_xyz 'x, y, z'
loop_ _atom_site_label _atom_site_occupancy _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_thermal_displace_type _atom_site_B_iso_or_equiv _atom_site_type_symbol Pd1
1.0000 0.93480 0.33972 0.30834 Biso 1.000 Pd
Pd2
1.0000 0.85788 0.64741 0.30834 Biso 1.000 Pd
Pd3
1.0000 0.16557 0.41664 0.30834 Biso 1.000 Pd
Pd4
1.0000 0.78095 0.95510 0.30834 Biso 1.000 Pd
Pd5
1.0000 0.08865 0.72433 0.30834 Biso 1.000 Pd
Pd6
1.0000 0.39634 0.49356 0.30834 Biso 1.000 Pd
Pd7
1.0000 0.01172 0.03203 0.30834 Biso 1.000 Pd
Pd8
1.0000 0.31941 0.80126 0.30834 Biso 1.000 Pd
Pd9
1.0000 0.62711 0.57049 0.30834 Biso 1.000 Pd
Pd10
1.0000 0.55018 0.87818 0.30834 Biso 1.000 Pd
Pd11
1.0000 0.80659 0.51921 0.39621 Biso 1.000 Pd
Pd12
1.0000 0.11429 0.28844 0.39621 Biso 1.000 Pd
Pd13
1.0000 0.72967 0.82690 0.39621 Biso 1.000 Pd
Pd14
1.0000 0.03736 0.59613 0.39621 Biso 1.000 Pd
Pd15
1.0000 0.34506 0.36536 0.39621 Biso 1.000 Pd
Pd16
1.0000 0.96044 0.90382 0.39621 Biso 1.000 Pd
Pd17
1.0000 0.26813 0.67305 0.39621 Biso 1.000 Pd
Pd18
1.0000 0.57582 0.44228 0.39621 Biso 1.000 Pd
Pd19
1.0000 0.19121 0.98074 0.39621 Biso 1.000 Pd
Pd20
1.0000 0.49890 0.74997 0.39621 Biso 1.000 Pd
Pd21
1.0000 0.67976 0.69817 0.48395 Biso 1.000 Pd
Pd22
1.0000 0.98664 0.46819 0.48418 Biso 1.000 Pd
Pd23
1.0000 0.60111 0.00665 0.48390 Biso 1.000 Pd
Pd24
1.0000 0.90957 0.77525 0.48414 Biso 1.000 Pd
Pd25
1.0000 0.21746 0.54477 0.48405 Biso 1.000 Pd
Pd26
1.0000 0.14035 0.85286 0.48432 Biso 1.000 Pd
Pd27
1.0000 0.44734 0.62286 0.48414 Biso 1.000 Pd
Pd28
1.0000 0.37023 0.92997 0.48415 Biso 1.000 Pd
Pd29
1.0000 0.24249 0.10895 0.30834 Biso 1.000 Pd
Pd30
1.0000 0.47326 0.18587 0.30834 Biso 1.000 Pd
Pd31
1.0000 0.70403 0.26279 0.30834 Biso 1.000 Pd
Pd32
1.0000 0.42198 0.05767 0.39621 Biso 1.000 Pd
Pd33
1.0000 0.65275 0.13459 0.39621 Biso 1.000 Pd
Pd34
1.0000 0.88352 0.21151 0.39621 Biso 1.000 Pd
Pd35
1.0000 0.06350 0.16064 0.48403 Biso 1.000 Pd
Pd36
1.0000 0.29416 0.23713 0.48461 Biso 1.000 Pd
Pd37
1.0000 0.52507 0.31349 0.48432 Biso 1.000 Pd
Pd38
1.0000 0.83206 0.08380 0.48417 Biso 1.000 Pd
Pd39
1.0000 0.75509 0.39043 0.48404 Biso 1.000 Pd
Pd40
1.0000 0.93490 0.33963 0.57282 Biso 1.000 Pd
Pd41
1.0000 0.85922 0.64675 0.57315 Biso 1.000 Pd
Pd42
1.0000 0.16650 0.41631 0.57401 Biso 1.000 Pd
Pd43
1.0000 0.78161 0.95502 0.57303 Biso 1.000 Pd
Pd44
1.0000 0.08954 0.72468 0.57340 Biso 1.000 Pd
Pd45
1.0000 0.39629 0.49444 0.57302 Biso 1.000 Pd
Pd46
1.0000 0.01149 0.03240 0.57338 Biso 1.000 Pd
Pd47
1.0000 0.32022 0.80185 0.57354 Biso 1.000 Pd
Pd48
1.0000 0.62791 0.57059 0.57313 Biso 1.000 Pd
Pd49
1.0000 0.55117 0.87835 0.57243 Biso 1.000 Pd
Pd50
1.0000 0.24275 0.10929 0.57415 Biso 1.000 Pd
Pd51
1.0000 0.47355 0.18592 0.57435 Biso 1.000 Pd
Pd52
1.0000 0.70358 0.26352 0.57351 Biso 1.000 Pd
O1
1.0000 0.10509 0.75243 0.68643 Biso 1.000 O
Ti1
1.0000 0.61122 0.92970 0.66363 Biso 1.000 Ti
O2
1.0000 0.44004 0.08883 0.68980 Biso 1.000 O
O3
1.0000 0.77232 0.94449 0.68695 Biso 1.000 O
Ti2
1.0000 0.94665 0.26262 0.66566 Biso 1.000 Ti
O4
1.0000 0.10923 0.27155 0.69018 Biso 1.000 O
O5
1.0000 0.96148 0.08621 0.68827 Biso 1.000 O
O6
1.0000 0.77436 0.42011 0.69259 Biso 1.000 O
Ti3
1.0000 0.27999 0.26142 0.66393 Biso 1.000 Ti
Ti4
1.0000 0.28233 0.59095 0.66358 Biso 1.000 Ti
O7
1.0000 0.43692 0.61121 0.69012 Biso 1.000 O
O8
1.0000 0.29352 0.42037 0.69010 Biso 1.000 O
O9
1.0000 0.62971 0.75528 0.69015 Biso 1.000 O
Ti5
1.0000 0.61450 0.59411 0.66768 Biso 1.000 Ti
Ti6
1.0000 0.94726 0.92782 0.66189 Biso 1.000 Ti
100-Doublelayer data_image0 _cell_length_a
5.58418
_cell_length_b
11.1684
_cell_length_c
23.5258
_cell_angle_alpha 90 _cell_angle_beta
90
_cell_angle_gamma
90
loop_ _atom_site_label _atom_site_occupancy _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_thermal_displace_type _atom_site_B_iso_or_equiv _atom_site_type_symbol Pd1
1.0000 0.25000 0.12500 0.25504 Biso 1.000 Pd
Pd2
1.0000 0.00000 0.00000 0.33896 Biso 1.000 Pd
Pd3
1.0000 0.24649 0.12599 0.42368 Biso 1.000 Pd
Pd4
1.0000 0.99235 0.00087 0.50911 Biso 1.000 Pd
Pd5
1.0000 0.25000 0.37500 0.25504 Biso 1.000 Pd
Pd6
1.0000 0.00000 0.25000 0.33896 Biso 1.000 Pd
Pd7
1.0000 0.24692 0.37545 0.42319 Biso 1.000 Pd
Pd8
1.0000 0.99421 0.25367 0.50966 Biso 1.000 Pd
Pd9
1.0000 0.25000 0.62500 0.25504 Biso 1.000 Pd
Pd10
1.0000 0.00000 0.50000 0.33896 Biso 1.000 Pd
Pd11
1.0000 0.24683 0.62531 0.42367 Biso 1.000 Pd
Pd12
1.0000 0.99734 0.50095 0.50924 Biso 1.000 Pd
Pd13
1.0000 0.25000 0.87500 0.25504 Biso 1.000 Pd
Pd14
1.0000 0.00000 0.75000 0.33896 Biso 1.000 Pd
Pd15
1.0000 0.24764 0.87514 0.42339 Biso 1.000 Pd
Pd16
1.0000 0.99527 0.75346 0.50893 Biso 1.000 Pd
Pd17
1.0000 0.75000 0.12500 0.25504 Biso 1.000 Pd
Pd18
1.0000 0.50000 0.00000 0.33896 Biso 1.000 Pd
Pd19
1.0000 0.74679 0.12538 0.42364 Biso 1.000 Pd
Pd20
1.0000 0.49723 0.00095 0.50912 Biso 1.000 Pd
Pd21
1.0000 0.75000 0.37500 0.25504 Biso 1.000 Pd
Pd22
1.0000 0.50000 0.25000 0.33896 Biso 1.000 Pd
Pd23
1.0000 0.74771 0.37526 0.42345 Biso 1.000 Pd
Pd24
1.0000 0.49534 0.25357 0.50893 Biso 1.000 Pd
Pd25
1.0000 0.75000 0.62500 0.25504 Biso 1.000 Pd
Pd26
1.0000 0.50000 0.50000 0.33896 Biso 1.000 Pd
Pd27
1.0000 0.74650 0.62590 0.42373 Biso 1.000 Pd
Pd28
1.0000 0.49241 0.50101 0.50930 Biso 1.000 Pd
Pd29
1.0000 0.75000 0.87500 0.25504 Biso 1.000 Pd
Pd30
1.0000 0.50000 0.75000 0.33896 Biso 1.000 Pd
Pd31
1.0000 0.74686 0.87532 0.42314 Biso 1.000 Pd
Pd32
1.0000 0.49405 0.75368 0.50967 Biso 1.000 Pd
Ti1
1.0000 0.24135 0.05485 0.59372 Biso 1.000 Ti
O1
1.0000 0.53631 0.98862 0.63399 Biso 1.000 O
Ti2
1.0000 0.56451 0.03737 0.70964 Biso 1.000 Ti
O2
1.0000 0.58900 0.20357 0.71767 Biso 1.000 O
O3
1.0000 0.80008 0.94126 0.73741 Biso 1.000 O
O4
1.0000 0.29926 0.96409 0.73799 Biso 1.000 O
Ti3
1.0000 0.24565 0.36602 0.58736 Biso 1.000 Ti
Ti4
1.0000 0.56517 0.37001 0.70834 Biso 1.000 Ti
O5
1.0000 0.30142 0.44295 0.73713 Biso 1.000 O
O6
1.0000 0.21557 0.20992 0.61921 Biso 1.000 O
O7
1.0000 0.03989 0.92512 0.63327 Biso 1.000 O
Ti5
1.0000 0.74158 0.55550 0.59369 Biso 1.000 Ti
O8
1.0000 0.71624 0.71087 0.61922 Biso 1.000 O
O9
1.0000 0.03711 0.48911 0.63369 Biso 1.000 O
O10
1.0000 0.54111 0.42378 0.63313 Biso 1.000 O
Ti6
1.0000 0.06484 0.53797 0.70930 Biso 1.000 Ti
O11
1.0000 0.09006 0.70388 0.71734 Biso 1.000 O
O12
1.0000 0.79921 0.46513 0.73762 Biso 1.000 O
Ti7
1.0000 0.74526 0.86677 0.58729 Biso 1.000 Ti
Ti8
1.0000 0.06477 0.86991 0.70835 Biso 1.000 Ti
References 1. Cargnello, M.; Doan-Nguyen, V. V.; Gordon, T. R.; Diaz, R. E.; Stach, E. A.; Gorte, R. J.; Fornasiero, P.; Murray, C. B. Science 2013, 341, 771-773. 2. Peng, S.; Lee, Y.; Wang, C.; Yin, H.; Dai, S.; Sun, S. Nano research 2008, 1, 229-234. 3. Zhang, S.; Chen, C.; Cargnello, M.; Fornasiero, P.; Gorte, R. J.; Graham, G. W.; Pan, X. Nature communications 2015, 6, 8778. 4. Giannozzi, P.; Baroni, S.; Bonini, N.; Calandra, M.; Car, R.; Cavazzoni, C.; Ceresoli, D.; Chiarotti, G. L.; Cococcioni, M.; Dabo, I. J. Phys.: Condens. Matter 2009, 21, 395502. 5. Vanderbilt, D. Physical Review B 1990, 41, 7892-7895. 6. Bengtsson, L. Physical Review B 1999, 59, 12301-12304. 7. Dulub, O.; Hebenstreit, W.; Diebold, U. Phys. Rev. Lett. 2000, 84, 3646. 8. Barcaro, G.; Sedona, F.; Fortunelli, A.; Granozzi, G. The Journal of Physical Chemistry C 2007, 111, 6095-6102. 9. Batson, P. E. Microsc. Microanal. 2008, 14, 89-97. 10. Krivanek, O. L.; Dellby, N.; Murfitt, M. F.; Chisholm, M. F.; Pennycook, T. J.; Suenaga, K.; Nicolosi, V. Ultramicroscopy 2010, 110, 935-945. 11. Chi, M.; Wang, C.; Lei, Y.; Wang, G.; Li, D.; More, K. L.; Lupini, A.; Allard, L. F.; Markovic, N. M.; Stamenkovic, V. R. Nature communications 2015, 6, 8925. 12. Lupini, A.; Krivanek, O.; Dellby, N.; Nellist, P.; Pennycook, S. In Developments in C~ s-corrected STEM, CONFERENCE SERIES-INSTITUTE OF PHYSICS, 2001; Philadelphia; Institute of Physics; 1999: pp 31-34.
1
Department of Chemical Engineering and Materials Science, University of California -
Irvine, Irvine, California 92697, USA. 2
Department of Materials Science and Engineering, University of Michigan, Ann Arbor,
Michigan 48109, USA. 3
SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator
Laboratory, Menlo Park, California 94025, USA. 4
Department of Chemical Engineering and SUNCAT Center for Interface Science and
Catalysis, Stanford University, Stanford, California 94305, USA. 5
Department of Physics and Astronomy, University of California - Irvine, Irvine,
California 92697, USA. § Present
address: Institute of Catalysis Research and Technology (IKFT), Hermann-von-
Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany. *Corresponding Author, Email: [email protected]
Supplementary Materials: Materials and Methods Figures S1-S20 Table S1-S3
Supplementary Materials
Materials and Methods Synthesis of Pd/TiO2, Pt/TiO2, Au/TiO2 samples The supported catalyst systems were prepared by deposition of pre-formed metal nanocrystals onto commercial titania P25 (Sigma-Aldrich). Pd and Pt nanocrystals were synthesized according to reference 1, whereas Au nanocrystals followed reference 2. The conditions were: Pd nanocrystals A mixture of 0.25 mmol Pd(acac)2, 2.5 mmol oleylamine, 1.25 mmol trioctylphosphine, 1.25 mmol oleic acid, 6.6 mL 1-octadecene, 3.4 mL 1-tetradecene, reaction at 290 °C for 15 minutes. Pt nanocrystals A mixture of 0.25 mmol Pt(acac)2, 2.0 mmol oleylamine, 0.5 mmol trioctylphosphine, 4.0 mmol oleic acid, 10 mL of trioctylamine were reacted at 30 °C for 30 minutes. Au nanocrystals A mixture of 100 mg HAuCl4, 10 mL oleylamine (80-90%, Acros), 10 mL tetraline, were dissolved and reacted at room temperature with a solution of 0.5 mmol of tributylamine borane complex (Sigma-Aldrich) in 1 mL oleylamine and 1 mL tetraline. The purified nanocrystals dissolved in hexanes at appropriate concentrations were added to a stirred solution of titania P25 in toluene (40 mL) in order to obtain a final loading of 0.5 wt. % in metal. The samples were left stirring for 30 minutes. Powders were collected by centrifugation, dried overnight and the organic ligands removed following a fast thermal treatment in a furnace at 700 °C for 30 seconds.
Characterization techniques In situ TEM was conducted on a JEOL 3100-R05 microscope with double Cs-correctors operated at 300 kV using the Protochips Atmosphere system as described before 3, and EELS data was acquired with Gatan #965 Quantum Imaging Filter (GIF) for electron energy loss spectroscopy and imaging. The purity of the gases used in the in situ experiment was 99.9995%. All reported temperatures are based on the Protochips calibration. DFT calculation DFT-calculations have been carried out with Quantum Espresso 4 using ultrasoft pseudopotentials5 and Fermi-Dirac smearing with kBT = 0.1 eV, except for gas-phase molecules, where integer occupation numbers have been enforced. The energy cut-off for the plane wave expansion of wave function (density) was 500 eV (5000 eV). We have used H2 and H2O as reference gas-phase molecules and the O2-reference was obtained using its experimental binding energy corrected by the zero-point energy: E(O2) = E(H2O) – E(H2) + 2.75 eV. Γ-centered k-point sampling was used in all cases. Generally we employed a kpoint-density roughly corresponding to (12×12×1) per (1×1)-Pd-fcc(111) surface unit cell. This has been found to give sufficiently converged energies (see below). Slabs were separated by about 16 Å and the dipole correction has additionally been used to reduce the artificial interaction between slabs 6. All presented number have been obtained using non spin-polarized calculations. We have thoroughly tested many structures for spin-polarized solutions. However, despite using strongly magnetic guesses for the initial wave function, all converged solutions were non-magnetic. This is in agreement with calculations reported for TiOx overlayers
7, 8
. To avoid convergence issues with surface energies, they were
calculated using the ’linear-fit’ method, e.g. the bulk reference energy was obtained by linear regression of the total slab-energies with respect to the number of layers. The free energy of solids and surfaces is approximated by their electronic energies. Free energies of gas phase molecules were obtained using the usual corrections from statistical thermodynamics for translation, (harmonic) oscillation and (rigid) rotation.
Estimate of experimental condition Double layer: The cell was purged with pure N2 (purity 99.9995%) and pumped to 0.1 Torr twice before it was filled with 760 Torr 5%H2/Ar (purity 99.9995%). Assuming air at saturated water vapor, ~17 Torr at 20 °C, can go into the cell during assembling and dissembling, the calculated water vapor concentration upon pump/purging would be 0.3×10-6 bar. On the other hand, considering the impurity of the forming gas, the residual H2O and O2 will result in a concentration of 0.6 ppm H2O, corresponding to 0.6×10-6 bar. Therefore, we assume that the initial water pressure is 10-6 bar or lower and will use 10-6 bar here as the upper limit. The experimental equilibrium constant (K in bar-0.5) for the reaction 0.5 O2 + H2 H2O is at T = 700 K log10(K) = 15.582 and log10(K) = 13.287 at T = 800 K. With K = p(H2O) / ( p(H2) * p(O2)0.5) It follows that p(O2) ~ 10-41 bar at T = 700 K and p(O2) ~ 10-36 bar at T = 800 K. Using the experimental reaction energy and employing the usual corrections from statistical thermodynamics for translation, (harmonic) oscillation, (rigid) rotation, we obtain for T = 773.15 K, p(H2)=0.05 bar, p(H2O)= 10-6 bar, µO = -3.7 eV. The experimental condition would be located at somewhere smaller than -3.7 eV. Single layer: The cell was filled with a mixture 15 Torr O2 and 745 Torr 5% H2/Ar. If equilibrium is reached, p(H2)=0.01 bar and p(H2O)=0.04 bar, using the same equation shown in the double layer formation condition, we obtain µO ~ -2.8 eV. No layer The cell was filled with a mixture of 43 Torr O2 and 720 Torr 5% H2/Ar. If equilibrium is reached, p(O2) =0.032 bar and p(H2O)= 0.048 bar, and the corresponding chemical potential would be µO ~ -0.9 eV.
Figure S1
Ex situ BF STEM images showing that the surfaces of the Pd particles are initially (i.e., before conducting the in-situ experiments) clean at room temperature.
Figure S2
ABF STEM images taken in situ showing that most of the Pd particles in Pd/TiO2 are covered by a thin amorphous layer at 300 °C under H2 (5 vol. %)/Ar at 1 atm.
Figure S3
ABF STEM images showing that no change occurred when Pd/Al2O3 was heated under H2 (5 vol. %)/Ar at 1 atm total pressure at 500 °C. The shape of the Pd nanoparticle is a truncated octahedron with smooth truncation between the two major facets, (111) and (100).
Figure S4-S6 Beam effect considerations We are aware that beam effects could possibly create artifacts. All the images were taken with a significantly reduced probe current, ~7 pA, while the probe current for normal STEM imaging is between 50-100 pA 9, 10. To minimize beam effect, Chi et al. used 20 pA probe current to study in-situ surface faceting of metal particles of similar size 11. Our probe size is estimated to be about 0.8 Å, which is typical for state-of-the-art aberration corrected STEM (1.3 Å after the membrane), before crossing the membrane of the cell. Our current density is 4 pA/Å2 , about 1 to 2 orders of magnitude lower than typical values
12
. Our
electron dose could go up to 104 e/Å2 to acquire the highest quality image, but we immediately reduced it to less than 100 e/Å2 after image acquisition. One direct way to identify the occurrence of electron beam damage is to record images of the same area before and after irradiation and compare the contrast under the same imaging conditions. No change was found when the samples were illuminated with the same conditions for prolonged time, as shown in the figures below. At a relatively higher oxygen potential (H2 (4.7 vol. %)/O2 (5.7 vol. %)/Ar, µO~ -0.9eV), the surfaces of Pd particles stayed clean at 500 °C during 20 min observation, as shown in Figure S4. At lower oxygen potential (H2 (5 vol. %)/Ar, µO< -3.7 eV), an amorphous layer starts to migrate onto the particles at temperatures around 250 °C. During 15 min observation at 250 °C under H2 (5 vol. %)/Ar at 1 atm, no change was observed, as shown in Figure S5. Finally, when the temperature was raised to 500 °C under the same gas atmosphere (H2 (5 vol. %)/Ar at 1 atm), two crystalline layers were instantaneously formed, and they were observed to be very stable under the beam illumination for 90 min, as shown in Figure S6. Furthermore, as shown in Figures S3 and S10, no over layer formed when the support material was changed to Al2O3, or the metal was changed to Au, suggesting the formation of the over layer is material dependent but not electron beam dependent. Thus, we believe that the electron beam didn’t play a significant role in any of the phenomena reported in this paper.
Figure S4 ABF images showing that no amorphous layer migrate onto the particle under H2 (4.7 vol. %)/O2 (5.7 vol. %)/Ar at 500 °C during 20mins electron beam illumination.
Figure S5 ABF images showing that an amorphous layer start to form on the surface of the particle at 250 °C under H2 (5 vol. %)/Ar at 1 atm and no changes have been observed in the images taken at varied time.
Figure S6 Pairs of HAADF and ABF images showing that no structural damage can be discerned in the images taken at varied time up to 90 mins of illumination at 500 °C under H2 (5 vol. %)/Ar at 1 atm.
Figure S7
ABF images showing more examples of double TiOx layer formed under H2 (5 vol. %)/Ar at 1 atm at 500 °C (A,B) and single layer formed under H2 (4.9 vol. %)/O2 (2 vol. %)/Ar at 1 atm at 500 °C (C,D).
Figure S8
Original ABF images (A-C) and HAADF image (A’-C’) of the false color images shown in Figure 2B-D.
Figure S9
ABF images showing the formation of TiOx double layer on Pt particles in Pt/TiO2 under H2 (5 vol. %)/Ar at 1 atm.
Figure S10
ABF images showing that the surface of Au particles in Au/TiO2 are clean after 1 h heating under H2 (5 vol. %)/Ar at 1 atm at 500 °C.
DFT calculation result of Pt and Au We have computed the thermodynamic stability of k-phase single and double layers of TiOx in the (1×1)/(2×2) super cell on Pt and Au, as well as Pd. Generally, both overlayers are stable on Pd and Pt and unstable on Au. Table S1 Comparison of the stability of the k-phase single and double layers of TiOx on the (111) facets of different metals on at μO = -3.7 eV. Free energies of formation are given in eV.
single
double
Au
0.04
0.18
Pd
-0.23
-0.19
Pt
-0.32
-0.40
Figure S11
Stability of k-phase single and double-layer TiOx structures supported on (111) Au, Pd and Pt. The number of layers is given in parentheses.
Figure S12 Wulff construction 𝛾100 𝛾111
ℎ
𝑁
= ℎ100 = √3 𝑁𝑇 111
𝑝
γ is the surface energy of specific plane and h is the distance from the center of the supported NP. The diameter of the NP is given by(𝑎0 /√2) ∙ 𝑁𝑃 . So Np is the number of atomic rows along diameter and NT is the number of atomic layers from the top to the center as shown below. The tilting of the particle doesn’t affect the counting of NP and NT.
Schematic showing NP and NT
Figure S13
Dynamic process showing the disorder to order transition accompanied by the faceting of the particle under 760 Torr 5%H2/N2 (A) 300 °C (B) 400 °C 2 min (C) 400 °C 15 min (D) 400 °C 47 min (E) 500 °C.
Figure S14
ABF images showing that after ex situ reduction conducted in a tube furnace for 1 hr at 500 °C under H2 (5 vol. %)/Ar, Pd particles in Pd/TiO2 are covered by a thin amorphous layer, which is in accordance with most of the literature reports. No crystalline layer can be discerned.
More Details of the DFT calculations Convergence Tests We have tested the accuracy resulting from different k-point sampling and plane wave cutoffs for mono- and double-layer of the k-phase for the smallest supercell, 1×1/2×2. As shown in Table S2, we expect the chosen plane-wave cutoff (500 eV) to give energies that are accurate to 0.01 eV per Ti atom. A similar accuracy is reached with a 8x8x1 kpoint sampling. Using a sampling of 6×6×1 results in an error of about 0.03 eV, which is still acceptable. Table S2 Formation energy (eV) of double and monolayer in a 1x1/2x2 supercell as a function of k-point sampling and wave function plane-wave cutoff. monolayer
monolayer
double-layer
double-layer
Eform / n(Ti)
Eform / n(Ti)
Eform / n(Ti)
Eform / n(Ti)
Cutoff
k-points
1000 eV
4x4x1
1.317
0.027
3.117
0.024
1000 eV
6x6x1
1.261
-0.029
3.060
-0.033
1000 eV
8x8x1
1.302
0.013
3.106
0.013
1000 eV
10x10x1
1.296
0.007
3.097
0.004
1000 eV
12x12x1
1.289 := 0
400 eV
8x8x1
1.288
-0.014
3.076
-0.031
500 eV
8x8x1
1.306
0.004
3.098
-0.008
600 eV
8x8x1
1.307
0.005
3.111
0.004
800 eV
8x8x1
1.302
0.000
3.107
0.001
1000 eV
8x8x1
1.302 := 0
3.093 :=0
3.106 :=0
Lattice mismatch Before turning to minimizing the lattice mismatch, it is important to realize that it is to some extent depending on temperature and partial pressures. As µO determines the stability of an overlayer, the same overlayer in different supercells with different deficiency of oxygen per unit cell will lead to different slopes in the plot of free energy of formation versus µO. This is shown below for two stable supercells of the single layer k-phase structure. The super cell with higher coverage of the k-phase, (1×1)/(2×2), is more oxygendefiant per surface area. Consequently the slope is larger and this structure is more stable at lower µO, while the other is more stable at µO. The crossover occurs in the relevant region of µO. Since the difference is not large, we pick the less dense unit cell, because this is the supercell in which the double layer is most stable. Figure S15
Stability of Pd(111)-supported k-phase single layers with different coverages. The lattice constant of the overlayer has been varied by creating various supercells (see Table S3). The obtained free energy curve as a function of lattice mismatch is depicted at µO = -3.7 eV in Figures SX. This is the approximate crossover between single and double-layer. As mentioned above, two super-cells have similar stability for the single
layer, while for the double layer it is clear, which super cell is most stable. The reason for the stability of the single layer in this small unit cell is probably that both Ti-atoms are three-fold coordinated by Pd. For all other supercells this is not the case. This unit cell is therefore likely an anomaly in the generally well-behaved potential energy curve. For the double layer, this effect is expected to be weaker as the compression acts on both layers, while the effect of interface bonding affects only one layer. For the double layer, a continuous curve is obtained, both for single and double layer. Since the overlayer generally has different orientations with respect to the support, this means that the influence of the orientation is likely smaller. At higher lattice-constants, where the overlayer becomes unstable, two different orientations leading to the same lattice constant, (√3×√3)-R30°/(4×4) and (3×3)/(4√3×4√3)-R30°, give a very similar formation energy.
Table S3 Data used to determine the minimum lattice mismatch. The k-point density in one dimension is given by the number of Pd atoms in one direction times the number of k-points in this direction. Lengths supercell /Å
k-phase- k-point 1D-k-point 2 Pd layers 4 Pd layers layers density grid G / eV G / eV
(√3×√3)-R30°/ 5.81
double
2x2x1
7.2
-0.232
-0.241
single
2x2x1
7.2
-0.211
-0.228
double
3x3x1
10.8
-0.227
single
3x3x1
10.8
-0.217
double
4x4x1
14.4
-0.228
-0.226
single
4x4x1
14.4
-0.215
-0.216
double
1x1x1
7.0
-0.187
single
1x1x1
7.0
-0.194
double
2x2x1
14.0
-0.216
(√13×√13)-R14°
(2√3×2√3)-R30°/(7×7)
5.64
(1×1)/(2×2)
(4×4)/(5√3×5√3)-R30°
(√3×√3)-R30°/(4×4)
(3×3)/(4√3×4√3)-R30°
5.58
6.04
6.45
6.45
single
2x2x1
14.0
-0.205
double
6x6x1
12.0
-0.197
-0.189
single
6x6x1
12.0
-0.192
-0.225
double
1x1x1
8.7
-0.187
single
1x1x1
8.7
-0.200
double
2x2x1
8.0
0.094
single
2x2x1
8.0
-0.028
single
1x1x1
6.9
-0.053
Figure S16
Figure SX Formation free energies per Pd-surface atom plotted agains the k-phase lattice constant. Insets shows a top view of k-phase single layer structures in various lattice constants.
Overview Pd(111) supported structures As described in the main text, the most stable obtained structures are the single and double layer of the k-phase. Other likely alternatives, that would also be in agreement with the experimental cross section (see below), are rocksalt(111)-derived structures. Various of the more complex reported TiOx structures are derived from a layer of closed-packed Ti atoms with threefold coordinated oxygen atoms in the fcc-sites. We have modeled the nondefected TiO-overlayer in a (√3×√3)-R30°-TiO/(2×2)-Pd(111) cell. At relatively high O, the TiO-layer is found to be less stable than the Ti2O3 mono-layer, while its stability is competitive with the double layer of Ti2O3 at lower O. Within the accuracy of our calculations this does certainly not rule out the existence of the double layer of Ti2O3, but the high density and high oxygen deficiency of the TiO-monolayer will certainly make it the most stable structure at sufficiently low O. Figure S17
Stability of Pd(111)-supported structures. Structural representations are shown as insets.
Orientation and comparison to experimental cross-section All experimental images show rows of atoms along the view axis. It is therefore likely that this true for all three symmetry-equivalent axis of the support, although images for each particle were only taken along one axis. This means that each layer of the overlayer should have a hexagonal symmetry. The entire overlayer does not necessarily have a hexagonal symmetry, since the rotational symmetry axis can be centered at different positions, as is the case for the double layer. Being restricted to periodic boundary conditions, various lattice mismatches can only be explored by also introducing different orientations of overlayer with respect to support, as done above. The orientation of the overlayer seems to be less important energetically, although we cannot check that explicitly in most cases. In terms of the actual orientation, it is highly likely that the support and overlayer are aligned along a symmetric axes in the most stable system, although the energetic stabilization may be small per unit cell. There are two highly symmetric orientations, one would be to align the lattice vectors of the minimal unit cells. The other one would be to rotate either overlayer or support by 30°. Technically this can be realized by generating a (√3×√3)-R30°unit cell of either support or overlayer and aligning it with the corresponding other minimal unit cell. The first orientation is in disagreement with the experimentally observed cross section that shows rows of atoms along the view axis, the second is in agreement. We illustrate this for the supercell (2√3×2√3)-R30°/(7×7), which is not the most stable unit cell, probably because the overlayers are stretched too much.
Figure S18
Cross section of super cell in which the orientation of k-phase and Pd(111) agrees with the experimental cross section.
Testing overlayers that include hydrogen We have studied hydrogenated k-phase single- and double layers with one, two or three H atoms per unit cell, where hydrogen binds to the bridging oxygens, forming hydroxyl groups. This corresponds to coverages of 1/3, 2/3 and 1 in terms of the available oxygen atoms. Calculations have been carried out in the (1×1)/(2×2) supercells and since hydrogen adsorption was generally found to be unstable, we did not investigate other supercells. The Figure below shows the stability of the hydrogenated single and double layers. We have assumed a constant hydrogen partial pressure of 0.05 bar. This way the hydrogenated phases have the same slope of formation free energies with respect to the chemical potential of oxygen. The unit cell of the hydrogenated single layers is included for illustration. All hydrogenated overlayers are instable with respect to the bare overlayers and become increasingly unstable with higher H-coverage.
Figure S19
Stability of hydrogenated single and double layers. Structural models are shown in an inset.
Overlayers on Pd(100) Forming supercells with low lattice mismatch is more challenging since the minimal unit cell of Pd(100) is cubic and that of the k-phase is hexagonal. We have therefore generated a rectangular k-phase unit cell, which fits best onto a (2×5)-Pd(100) supercell. In the same way, we have generated a supercell with the hexagonal TiO structure on Pd(100). Additionally, we found a cubic structure that it is stable at low O. This cubic structure is the analagon to rocksalt(111)/Pd(111) for Pd(100): It is a continuation of the fcc(100) facet with one layer of Ti and one layer of oxygen.
Figure S20
Stability of Pd(100)-supported layers. Structural models are shown in an insets.
Cartesian coordinates of the most relevant structures Structures of the overlayers discussed in the main article are given in the .cif format below. 100-Monolayer data_image0 _cell_length_a
5.58418
_cell_length_b
11.1684
_cell_length_c
24.6238
_cell_angle_alpha 90 _cell_angle_beta
90
_cell_angle_gamma
loop_ _atom_site_label
90
_atom_site_occupancy _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_thermal_displace_type _atom_site_B_iso_or_equiv _atom_site_type_symbol Pd1
1.0000 0.25000 0.12500 0.32489 Biso 1.000 Pd
Pd2
1.0000 0.00000 0.00000 0.40507 Biso 1.000 Pd
Pd3
1.0000 0.25104 0.12605 0.48521 Biso 1.000 Pd
Pd4
1.0000 0.00101 0.00135 0.56587 Biso 1.000 Pd
Pd5
1.0000 0.25000 0.37500 0.32489 Biso 1.000 Pd
Pd6
1.0000 0.00000 0.25000 0.40507 Biso 1.000 Pd
Pd7
1.0000 0.25040 0.37606 0.48578 Biso 1.000 Pd
Pd8
1.0000 0.00356 0.25214 0.56577 Biso 1.000 Pd
Pd9
1.0000 0.25000 0.62500 0.32489 Biso 1.000 Pd
Pd10
1.0000 0.00000 0.50000 0.40507 Biso 1.000 Pd
Pd11
1.0000 0.25092 0.62514 0.48557 Biso 1.000 Pd
Pd12
1.0000 0.99394 0.50444 0.56678 Biso 1.000 Pd
Pd13
1.0000 0.25000 0.87500 0.32489 Biso 1.000 Pd
Pd14
1.0000 0.00000 0.75000 0.40507 Biso 1.000 Pd
Pd15
1.0000 0.25128 0.87590 0.48562 Biso 1.000 Pd
Pd16
1.0000 0.00889 0.75195 0.56676 Biso 1.000 Pd
Pd17
1.0000 0.75000 0.12500 0.32489 Biso 1.000 Pd
Pd18
1.0000 0.50000 0.00000 0.40507 Biso 1.000 Pd
Pd19
1.0000 0.75087 0.12509 0.48555 Biso 1.000 Pd
Pd20
1.0000 0.49398 0.00446 0.56684 Biso 1.000 Pd
Pd21
1.0000 0.75000 0.37500 0.32489 Biso 1.000 Pd
Pd22
1.0000 0.50000 0.25000 0.40507 Biso 1.000 Pd
Pd23
1.0000 0.75123 0.37589 0.48560 Biso 1.000 Pd
Pd24
1.0000 0.50869 0.25186 0.56665 Biso 1.000 Pd
Pd25
1.0000 0.75000 0.62500 0.32489 Biso 1.000 Pd
Pd26
1.0000 0.50000 0.50000 0.40507 Biso 1.000 Pd
Pd27
1.0000 0.75108 0.62613 0.48523 Biso 1.000 Pd
Pd28
1.0000 0.50105 0.50131 0.56585 Biso 1.000 Pd
Pd29
1.0000 0.75000 0.87500 0.32489 Biso 1.000 Pd
Pd30
1.0000 0.50000 0.75000 0.40507 Biso 1.000 Pd
Pd31
1.0000 0.75042 0.87605 0.48581 Biso 1.000 Pd
Pd32
1.0000 0.50354 0.75217 0.56587 Biso 1.000 Pd
Ti1
1.0000 0.27223 0.07976 0.65715 Biso 1.000 Ti
Ti2
1.0000 0.74963 0.26602 0.65812 Biso 1.000 Ti
O1
1.0000 0.01818 0.17713 0.67268 Biso 1.000 O
Ti3
1.0000 0.77209 0.57909 0.65709 Biso 1.000 Ti
O2
1.0000 0.75339 0.42311 0.68119 Biso 1.000 O
O3
1.0000 0.51661 0.16838 0.68488 Biso 1.000 O
Ti4
1.0000 0.24969 0.76563 0.65828 Biso 1.000 Ti
O4
1.0000 0.25329 0.92348 0.68102 Biso 1.000 O
O5
1.0000 0.51761 0.67620 0.67278 Biso 1.000 O
O6
1.0000 0.01809 0.66651 0.68478 Biso 1.000 O
Monolayer, (√3×√3)-R30°/(√13×√13)-R14° data_image0 _cell_length_a
5.58418
_cell_length_b
5.58418
_cell_length_c
25.8005
_cell_angle_alpha 90 _cell_angle_beta
90
_cell_angle_gamma
120
loop_ _atom_site_label _atom_site_occupancy _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_thermal_displace_type _atom_site_B_iso_or_equiv _atom_site_type_symbol Pd1
1.0000 0.00000 0.00000 0.31007 Biso 1.000 Pd
Pd2
1.0000 0.33333 0.16667 0.39843 Biso 1.000 Pd
Pd3
1.0000 0.16517 0.33348 0.48756 Biso 1.000 Pd
Pd4
1.0000 0.99998 0.00003 0.57765 Biso 1.000 Pd
Pd5
1.0000 0.00000 0.50000 0.31007 Biso 1.000 Pd
Pd6
1.0000 0.33333 0.66667 0.39843 Biso 1.000 Pd
Pd7
1.0000 0.16825 0.83483 0.48757 Biso 1.000 Pd
Pd8
1.0000 0.00011 0.50645 0.57894 Biso 1.000 Pd
Pd9
1.0000 0.50000 0.00000 0.31007 Biso 1.000 Pd
Pd10
1.0000 0.83333 0.16667 0.39843 Biso 1.000 Pd
Pd11
1.0000 0.66665 0.33336 0.48746 Biso 1.000 Pd
Pd12
1.0000 0.50624 0.99988 0.57894 Biso 1.000 Pd
Pd13
1.0000 0.50000 0.50000 0.31007 Biso 1.000 Pd
Pd14
1.0000 0.83333 0.66667 0.39843 Biso 1.000 Pd
Pd15
1.0000 0.66653 0.83176 0.48756 Biso 1.000 Pd
Pd16
1.0000 0.49354 0.49376 0.57894 Biso 1.000 Pd
Ti1
1.0000 0.66635 0.33328 0.66061 Biso 1.000 Ti
Ti2
1.0000 0.99968 0.00009 0.66775 Biso 1.000 Ti
Ti3
1.0000 0.33316 0.66678 0.66096 Biso 1.000 Ti
O1
1.0000 0.66636 0.66649 0.68965 Biso 1.000 O
O2
1.0000 0.99968 0.33356 0.68965 Biso 1.000 O
O3
1.0000 0.33316 0.00013 0.68965 Biso 1.000 O
Doublelayer, (√3×√3)-R30°/(√13×√13)-R14°
data_image0 _cell_length_a
10.067
_cell_length_b
10.067
_cell_length_c
28.5747
_cell_angle_alpha 90 _cell_angle_beta
90
_cell_angle_gamma
60
_symmetry_space_group_name_H-M _symmetry_int_tables_number
P1
1
loop_ _symmetry_equiv_pos_as_xyz 'x, y, z'
loop_ _atom_site_label _atom_site_occupancy _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_thermal_displace_type _atom_site_B_iso_or_equiv _atom_site_type_symbol Pd1
1.0000 0.93480 0.33972 0.27997 Biso 1.000 Pd
Pd2
1.0000 0.85788 0.64741 0.27997 Biso 1.000 Pd
Pd3
1.0000 0.16557 0.41664 0.27997 Biso 1.000 Pd
Pd4
1.0000 0.78095 0.95510 0.27997 Biso 1.000 Pd
Pd5
1.0000 0.08865 0.72433 0.27997 Biso 1.000 Pd
Pd6
1.0000 0.39634 0.49356 0.27997 Biso 1.000 Pd
Pd7
1.0000 0.01172 0.03203 0.27997 Biso 1.000 Pd
Pd8
1.0000 0.31941 0.80126 0.27997 Biso 1.000 Pd
Pd9
1.0000 0.62711 0.57049 0.27997 Biso 1.000 Pd
Pd10
1.0000 0.55018 0.87818 0.27997 Biso 1.000 Pd
Pd11
1.0000 0.80659 0.51921 0.35975 Biso 1.000 Pd
Pd12
1.0000 0.11429 0.28844 0.35975 Biso 1.000 Pd
Pd13
1.0000 0.72967 0.82690 0.35975 Biso 1.000 Pd
Pd14
1.0000 0.03736 0.59613 0.35975 Biso 1.000 Pd
Pd15
1.0000 0.34506 0.36536 0.35975 Biso 1.000 Pd
Pd16
1.0000 0.96044 0.90382 0.35975 Biso 1.000 Pd
Pd17
1.0000 0.26813 0.67305 0.35975 Biso 1.000 Pd
Pd18
1.0000 0.57582 0.44228 0.35975 Biso 1.000 Pd
Pd19
1.0000 0.19121 0.98074 0.35975 Biso 1.000 Pd
Pd20
1.0000 0.49890 0.74997 0.35975 Biso 1.000 Pd
Pd21
1.0000 0.67875 0.69758 0.43913 Biso 1.000 Pd
Pd22
1.0000 0.98624 0.46960 0.43972 Biso 1.000 Pd
Pd23
1.0000 0.59836 0.00651 0.43961 Biso 1.000 Pd
Pd24
1.0000 0.90860 0.77556 0.43998 Biso 1.000 Pd
Pd25
1.0000 0.21647 0.54572 0.43959 Biso 1.000 Pd
Pd26
1.0000 0.13895 0.85406 0.44110 Biso 1.000 Pd
Pd27
1.0000 0.44520 0.62238 0.43987 Biso 1.000 Pd
Pd28
1.0000 0.36829 0.92918 0.44031 Biso 1.000 Pd
Pd29
1.0000 0.24249 0.10895 0.27997 Biso 1.000 Pd
Pd30
1.0000 0.47326 0.18587 0.27997 Biso 1.000 Pd
Pd31
1.0000 0.70403 0.26279 0.27997 Biso 1.000 Pd
Pd32
1.0000 0.42198 0.05767 0.35975 Biso 1.000 Pd
Pd33
1.0000 0.65275 0.13459 0.35975 Biso 1.000 Pd
Pd34
1.0000 0.88352 0.21151 0.35975 Biso 1.000 Pd
Pd35
1.0000 0.06349 0.15979 0.43977 Biso 1.000 Pd
Pd36
1.0000 0.29314 0.23698 0.44105 Biso 1.000 Pd
Pd37
1.0000 0.52398 0.31161 0.44082 Biso 1.000 Pd
Pd38
1.0000 0.83128 0.08390 0.44033 Biso 1.000 Pd
Pd39
1.0000 0.75465 0.38877 0.43909 Biso 1.000 Pd
Pd40
1.0000 0.93481 0.34191 0.51826 Biso 1.000 Pd
Pd41
1.0000 0.85490 0.64958 0.52131 Biso 1.000 Pd
Pd42
1.0000 0.16171 0.42405 0.52230 Biso 1.000 Pd
Pd43
1.0000 0.77523 0.95540 0.51986 Biso 1.000 Pd
Pd44
1.0000 0.08307 0.73108 0.52252 Biso 1.000 Pd
Pd45
1.0000 0.39694 0.48932 0.52086 Biso 1.000 Pd
Pd46
1.0000 0.00688 0.03578 0.52404 Biso 1.000 Pd
Pd47
1.0000 0.31743 0.79843 0.52448 Biso 1.000 Pd
Pd48
1.0000 0.62819 0.56541 0.51812 Biso 1.000 Pd
Pd49
1.0000 0.54612 0.87187 0.51988 Biso 1.000 Pd
Pd50
1.0000 0.23981 0.10778 0.52321 Biso 1.000 Pd
Pd51
1.0000 0.47249 0.18111 0.52520 Biso 1.000 Pd
Pd52
1.0000 0.70379 0.26031 0.52330 Biso 1.000 Pd
O1
1.0000 0.07255 0.74559 0.63135 Biso 1.000 O
Ti1
1.0000 0.58774 0.95668 0.59390 Biso 1.000 Ti
O2
1.0000 0.40339 0.08856 0.63124 Biso 1.000 O
O3
1.0000 0.75169 0.94820 0.62433 Biso 1.000 O
Ti2
1.0000 0.91760 0.26264 0.59430 Biso 1.000 Ti
O4
1.0000 0.07140 0.27834 0.62348 Biso 1.000 O
O5
1.0000 0.94980 0.07876 0.63129 Biso 1.000 O
O6
1.0000 0.73073 0.42214 0.62745 Biso 1.000 O
Ti3
1.0000 0.23787 0.26500 0.59247 Biso 1.000 Ti
Ti4
1.0000 0.25852 0.59148 0.59290 Biso 1.000 Ti
O7
1.0000 0.40360 0.62300 0.62322 Biso 1.000 O
O8
1.0000 0.27933 0.41487 0.63002 Biso 1.000 O
O9
1.0000 0.61204 0.76328 0.62915 Biso 1.000 O
Ti5
1.0000 0.57011 0.61773 0.59698 Biso 1.000 Ti
Ti6
1.0000 0.92448 0.92516 0.59424 Biso 1.000 Ti
O10
1.0000 0.20252 0.57891 0.71891 Biso 1.000 O
Ti7
1.0000 0.67460 0.73800 0.69247 Biso 1.000 Ti
O11
1.0000 0.53509 0.91588 0.71929 Biso 1.000 O
O12
1.0000 0.87073 0.69354 0.70098 Biso 1.000 O
Ti8
1.0000 0.00784 0.06684 0.69428 Biso 1.000 Ti
O13
1.0000 0.20296 0.02828 0.70119 Biso 1.000 O
O14
1.0000 0.98764 0.91351 0.72003 Biso 1.000 O
O15
1.0000 0.86464 0.25162 0.71738 Biso 1.000 O
Ti9
1.0000 0.35903 0.06735 0.69382 Biso 1.000 Ti
Ti10
1.0000 0.34077 0.39844 0.69279 Biso 1.000 Ti
O16
1.0000 0.53646 0.36022 0.69861 Biso 1.000 O
O17
1.0000 0.31859 0.24742 0.71956 Biso 1.000 O
O18
1.0000 0.64719 0.58542 0.71549 Biso 1.000 O
Ti11
1.0000 0.69016 0.40226 0.69129 Biso 1.000 Ti
Ti12
1.0000 0.02722 0.73283 0.69417 Biso 1.000 Ti
111: TiO-rocksalt(111) data_image0 _cell_length_a
10.067
_cell_length_b
10.067
_cell_length_c
25.9455
_cell_angle_alpha 90 _cell_angle_beta
90
_cell_angle_gamma
60
_symmetry_space_group_name_H-M _symmetry_int_tables_number
P1
1
loop_ _symmetry_equiv_pos_as_xyz 'x, y, z'
loop_ _atom_site_label _atom_site_occupancy _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_thermal_displace_type _atom_site_B_iso_or_equiv _atom_site_type_symbol Pd1
1.0000 0.93480 0.33972 0.30834 Biso 1.000 Pd
Pd2
1.0000 0.85788 0.64741 0.30834 Biso 1.000 Pd
Pd3
1.0000 0.16557 0.41664 0.30834 Biso 1.000 Pd
Pd4
1.0000 0.78095 0.95510 0.30834 Biso 1.000 Pd
Pd5
1.0000 0.08865 0.72433 0.30834 Biso 1.000 Pd
Pd6
1.0000 0.39634 0.49356 0.30834 Biso 1.000 Pd
Pd7
1.0000 0.01172 0.03203 0.30834 Biso 1.000 Pd
Pd8
1.0000 0.31941 0.80126 0.30834 Biso 1.000 Pd
Pd9
1.0000 0.62711 0.57049 0.30834 Biso 1.000 Pd
Pd10
1.0000 0.55018 0.87818 0.30834 Biso 1.000 Pd
Pd11
1.0000 0.80659 0.51921 0.39621 Biso 1.000 Pd
Pd12
1.0000 0.11429 0.28844 0.39621 Biso 1.000 Pd
Pd13
1.0000 0.72967 0.82690 0.39621 Biso 1.000 Pd
Pd14
1.0000 0.03736 0.59613 0.39621 Biso 1.000 Pd
Pd15
1.0000 0.34506 0.36536 0.39621 Biso 1.000 Pd
Pd16
1.0000 0.96044 0.90382 0.39621 Biso 1.000 Pd
Pd17
1.0000 0.26813 0.67305 0.39621 Biso 1.000 Pd
Pd18
1.0000 0.57582 0.44228 0.39621 Biso 1.000 Pd
Pd19
1.0000 0.19121 0.98074 0.39621 Biso 1.000 Pd
Pd20
1.0000 0.49890 0.74997 0.39621 Biso 1.000 Pd
Pd21
1.0000 0.67976 0.69817 0.48395 Biso 1.000 Pd
Pd22
1.0000 0.98664 0.46819 0.48418 Biso 1.000 Pd
Pd23
1.0000 0.60111 0.00665 0.48390 Biso 1.000 Pd
Pd24
1.0000 0.90957 0.77525 0.48414 Biso 1.000 Pd
Pd25
1.0000 0.21746 0.54477 0.48405 Biso 1.000 Pd
Pd26
1.0000 0.14035 0.85286 0.48432 Biso 1.000 Pd
Pd27
1.0000 0.44734 0.62286 0.48414 Biso 1.000 Pd
Pd28
1.0000 0.37023 0.92997 0.48415 Biso 1.000 Pd
Pd29
1.0000 0.24249 0.10895 0.30834 Biso 1.000 Pd
Pd30
1.0000 0.47326 0.18587 0.30834 Biso 1.000 Pd
Pd31
1.0000 0.70403 0.26279 0.30834 Biso 1.000 Pd
Pd32
1.0000 0.42198 0.05767 0.39621 Biso 1.000 Pd
Pd33
1.0000 0.65275 0.13459 0.39621 Biso 1.000 Pd
Pd34
1.0000 0.88352 0.21151 0.39621 Biso 1.000 Pd
Pd35
1.0000 0.06350 0.16064 0.48403 Biso 1.000 Pd
Pd36
1.0000 0.29416 0.23713 0.48461 Biso 1.000 Pd
Pd37
1.0000 0.52507 0.31349 0.48432 Biso 1.000 Pd
Pd38
1.0000 0.83206 0.08380 0.48417 Biso 1.000 Pd
Pd39
1.0000 0.75509 0.39043 0.48404 Biso 1.000 Pd
Pd40
1.0000 0.93490 0.33963 0.57282 Biso 1.000 Pd
Pd41
1.0000 0.85922 0.64675 0.57315 Biso 1.000 Pd
Pd42
1.0000 0.16650 0.41631 0.57401 Biso 1.000 Pd
Pd43
1.0000 0.78161 0.95502 0.57303 Biso 1.000 Pd
Pd44
1.0000 0.08954 0.72468 0.57340 Biso 1.000 Pd
Pd45
1.0000 0.39629 0.49444 0.57302 Biso 1.000 Pd
Pd46
1.0000 0.01149 0.03240 0.57338 Biso 1.000 Pd
Pd47
1.0000 0.32022 0.80185 0.57354 Biso 1.000 Pd
Pd48
1.0000 0.62791 0.57059 0.57313 Biso 1.000 Pd
Pd49
1.0000 0.55117 0.87835 0.57243 Biso 1.000 Pd
Pd50
1.0000 0.24275 0.10929 0.57415 Biso 1.000 Pd
Pd51
1.0000 0.47355 0.18592 0.57435 Biso 1.000 Pd
Pd52
1.0000 0.70358 0.26352 0.57351 Biso 1.000 Pd
O1
1.0000 0.10509 0.75243 0.68643 Biso 1.000 O
Ti1
1.0000 0.61122 0.92970 0.66363 Biso 1.000 Ti
O2
1.0000 0.44004 0.08883 0.68980 Biso 1.000 O
O3
1.0000 0.77232 0.94449 0.68695 Biso 1.000 O
Ti2
1.0000 0.94665 0.26262 0.66566 Biso 1.000 Ti
O4
1.0000 0.10923 0.27155 0.69018 Biso 1.000 O
O5
1.0000 0.96148 0.08621 0.68827 Biso 1.000 O
O6
1.0000 0.77436 0.42011 0.69259 Biso 1.000 O
Ti3
1.0000 0.27999 0.26142 0.66393 Biso 1.000 Ti
Ti4
1.0000 0.28233 0.59095 0.66358 Biso 1.000 Ti
O7
1.0000 0.43692 0.61121 0.69012 Biso 1.000 O
O8
1.0000 0.29352 0.42037 0.69010 Biso 1.000 O
O9
1.0000 0.62971 0.75528 0.69015 Biso 1.000 O
Ti5
1.0000 0.61450 0.59411 0.66768 Biso 1.000 Ti
Ti6
1.0000 0.94726 0.92782 0.66189 Biso 1.000 Ti
100-Doublelayer data_image0 _cell_length_a
5.58418
_cell_length_b
11.1684
_cell_length_c
23.5258
_cell_angle_alpha 90 _cell_angle_beta
90
_cell_angle_gamma
90
loop_ _atom_site_label _atom_site_occupancy _atom_site_fract_x _atom_site_fract_y _atom_site_fract_z _atom_site_thermal_displace_type _atom_site_B_iso_or_equiv _atom_site_type_symbol Pd1
1.0000 0.25000 0.12500 0.25504 Biso 1.000 Pd
Pd2
1.0000 0.00000 0.00000 0.33896 Biso 1.000 Pd
Pd3
1.0000 0.24649 0.12599 0.42368 Biso 1.000 Pd
Pd4
1.0000 0.99235 0.00087 0.50911 Biso 1.000 Pd
Pd5
1.0000 0.25000 0.37500 0.25504 Biso 1.000 Pd
Pd6
1.0000 0.00000 0.25000 0.33896 Biso 1.000 Pd
Pd7
1.0000 0.24692 0.37545 0.42319 Biso 1.000 Pd
Pd8
1.0000 0.99421 0.25367 0.50966 Biso 1.000 Pd
Pd9
1.0000 0.25000 0.62500 0.25504 Biso 1.000 Pd
Pd10
1.0000 0.00000 0.50000 0.33896 Biso 1.000 Pd
Pd11
1.0000 0.24683 0.62531 0.42367 Biso 1.000 Pd
Pd12
1.0000 0.99734 0.50095 0.50924 Biso 1.000 Pd
Pd13
1.0000 0.25000 0.87500 0.25504 Biso 1.000 Pd
Pd14
1.0000 0.00000 0.75000 0.33896 Biso 1.000 Pd
Pd15
1.0000 0.24764 0.87514 0.42339 Biso 1.000 Pd
Pd16
1.0000 0.99527 0.75346 0.50893 Biso 1.000 Pd
Pd17
1.0000 0.75000 0.12500 0.25504 Biso 1.000 Pd
Pd18
1.0000 0.50000 0.00000 0.33896 Biso 1.000 Pd
Pd19
1.0000 0.74679 0.12538 0.42364 Biso 1.000 Pd
Pd20
1.0000 0.49723 0.00095 0.50912 Biso 1.000 Pd
Pd21
1.0000 0.75000 0.37500 0.25504 Biso 1.000 Pd
Pd22
1.0000 0.50000 0.25000 0.33896 Biso 1.000 Pd
Pd23
1.0000 0.74771 0.37526 0.42345 Biso 1.000 Pd
Pd24
1.0000 0.49534 0.25357 0.50893 Biso 1.000 Pd
Pd25
1.0000 0.75000 0.62500 0.25504 Biso 1.000 Pd
Pd26
1.0000 0.50000 0.50000 0.33896 Biso 1.000 Pd
Pd27
1.0000 0.74650 0.62590 0.42373 Biso 1.000 Pd
Pd28
1.0000 0.49241 0.50101 0.50930 Biso 1.000 Pd
Pd29
1.0000 0.75000 0.87500 0.25504 Biso 1.000 Pd
Pd30
1.0000 0.50000 0.75000 0.33896 Biso 1.000 Pd
Pd31
1.0000 0.74686 0.87532 0.42314 Biso 1.000 Pd
Pd32
1.0000 0.49405 0.75368 0.50967 Biso 1.000 Pd
Ti1
1.0000 0.24135 0.05485 0.59372 Biso 1.000 Ti
O1
1.0000 0.53631 0.98862 0.63399 Biso 1.000 O
Ti2
1.0000 0.56451 0.03737 0.70964 Biso 1.000 Ti
O2
1.0000 0.58900 0.20357 0.71767 Biso 1.000 O
O3
1.0000 0.80008 0.94126 0.73741 Biso 1.000 O
O4
1.0000 0.29926 0.96409 0.73799 Biso 1.000 O
Ti3
1.0000 0.24565 0.36602 0.58736 Biso 1.000 Ti
Ti4
1.0000 0.56517 0.37001 0.70834 Biso 1.000 Ti
O5
1.0000 0.30142 0.44295 0.73713 Biso 1.000 O
O6
1.0000 0.21557 0.20992 0.61921 Biso 1.000 O
O7
1.0000 0.03989 0.92512 0.63327 Biso 1.000 O
Ti5
1.0000 0.74158 0.55550 0.59369 Biso 1.000 Ti
O8
1.0000 0.71624 0.71087 0.61922 Biso 1.000 O
O9
1.0000 0.03711 0.48911 0.63369 Biso 1.000 O
O10
1.0000 0.54111 0.42378 0.63313 Biso 1.000 O
Ti6
1.0000 0.06484 0.53797 0.70930 Biso 1.000 Ti
O11
1.0000 0.09006 0.70388 0.71734 Biso 1.000 O
O12
1.0000 0.79921 0.46513 0.73762 Biso 1.000 O
Ti7
1.0000 0.74526 0.86677 0.58729 Biso 1.000 Ti
Ti8
1.0000 0.06477 0.86991 0.70835 Biso 1.000 Ti
References 1. Cargnello, M.; Doan-Nguyen, V. V.; Gordon, T. R.; Diaz, R. E.; Stach, E. A.; Gorte, R. J.; Fornasiero, P.; Murray, C. B. Science 2013, 341, 771-773. 2. Peng, S.; Lee, Y.; Wang, C.; Yin, H.; Dai, S.; Sun, S. Nano research 2008, 1, 229-234. 3. Zhang, S.; Chen, C.; Cargnello, M.; Fornasiero, P.; Gorte, R. J.; Graham, G. W.; Pan, X. Nature communications 2015, 6, 8778. 4. Giannozzi, P.; Baroni, S.; Bonini, N.; Calandra, M.; Car, R.; Cavazzoni, C.; Ceresoli, D.; Chiarotti, G. L.; Cococcioni, M.; Dabo, I. J. Phys.: Condens. Matter 2009, 21, 395502. 5. Vanderbilt, D. Physical Review B 1990, 41, 7892-7895. 6. Bengtsson, L. Physical Review B 1999, 59, 12301-12304. 7. Dulub, O.; Hebenstreit, W.; Diebold, U. Phys. Rev. Lett. 2000, 84, 3646. 8. Barcaro, G.; Sedona, F.; Fortunelli, A.; Granozzi, G. The Journal of Physical Chemistry C 2007, 111, 6095-6102. 9. Batson, P. E. Microsc. Microanal. 2008, 14, 89-97. 10. Krivanek, O. L.; Dellby, N.; Murfitt, M. F.; Chisholm, M. F.; Pennycook, T. J.; Suenaga, K.; Nicolosi, V. Ultramicroscopy 2010, 110, 935-945. 11. Chi, M.; Wang, C.; Lei, Y.; Wang, G.; Li, D.; More, K. L.; Lupini, A.; Allard, L. F.; Markovic, N. M.; Stamenkovic, V. R. Nature communications 2015, 6, 8925. 12. Lupini, A.; Krivanek, O.; Dellby, N.; Nellist, P.; Pennycook, S. In Developments in C~ s-corrected STEM, CONFERENCE SERIES-INSTITUTE OF PHYSICS, 2001; Philadelphia; Institute of Physics; 1999: pp 31-34.
