Perovskite Nanoparticle-Sensitized Ga2O3 Nanorod Arrays for CO ...
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Perovskite Nanoparticle-Sensitized Ga2O3 Nanorod Arrays for CO Detection at High Temperature Hui-Jan Lin,a John P. Baltrus,b Haiyong Gao,a Yong Ding,c Chang-Yong Nam,d Paul Ohodnicki, b, e Pu-Xian Gao a, * a
Department of Materials Science and Engineering & Institute of Materials Science, University of Connecticut, 97 North Eagleville Road, Storrs, Connecticut 06269-3136, United States b National Energy Technology Laboratory, 626 Cochrans Mill Road, Pittsburgh, Pennsylvania 15236, United States c School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, Georgia 30332, United States d Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States e Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15216, United States *Corresponding author e-mail: [email protected]
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Figure S1. Schematic illustration of a typical Ga2O3 nanorod array sensor testing setup, (1) Alumina holder, (2) Ga2O3-based nanorod array gas sensor fabricated on Si substrate, (3) ceramic screw and (4) platinum wires.
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Ga2O3 Ga2O3
Ga2O3 LSFO/Ga2O3 Pt/Ga2O3
LSFO/Ga2O3 Pt/Ga2O3 Pt/Ga2O3 LSFO/Ga2O3 Short Diagonal Length (nm) 175.75 173.33 181.58
Long Diagonal Length (nm) 320.22 328.67 331
Individual Wire
Individual Wire
400 300 200 100 0
Individual Wire Short Diagonal Length S.D.(nm) 21.09 27.76 17.61
Long Diagonal Length S.D.(nm) 34.2 24.24 28.3
Figure S2. (a) Comparison of short and long diagonal lengths of the diamond shape tips of β-Ga2O3, LSFO/Ga2O3 and Pt/Ga2O3 nanorod arrays and the corresponding detail lengths of randomly picked nanorods are shown in (b), (c) and (d), respectively. (d) The table of the calculated short and long lengths of each type. The insert in (a) shows the diamond-shaped tip of a GaOOH nanorod.
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(a)
(b) Pt 3.39%
La0.8Sr0.2FeO3 0.61% Fe 37.93%
Ga2O3 96.61%
Ga2O3 99.39%
La 55.17%
6.90% Sr
Figure S3. The ICP-MS composition analyses results of (a) 3 wt. % Pt on Ga2O3 nanorod arrays, (b) 5 nm LSFO/Ga2O3 nanorod arrays.
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17.14.24 Acquire EDX Preview HAADF Point 1
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Ga-K
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Figure S4. (a), (c), and (e) Typical HAADF STEM images of LSFO decorated β-Ga2O3 nanorods showing their porous structure; the corresponding EDS spectra from (b) point scanning, (d) and (e) line scanning revealing the existence and distribution of LSFO composition on β-Ga2O3 nanorods. The scale bar is 100 nm.
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Carbon Monoxide Oxygen Nitrogen
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CO Cylinder
N2 Cylinder N2 Cylinder
Vacuum_After Vacuum_After
Figure S5. Residual gas analysis of (a) dynamic partial pressure of CO, N2 and O2 in a sequence of vacuum in the Residual Gas Analyzer chamber, 2% CO balanced with N2 and ultra-high purity N2 cylinder, with each duration time of first three steps ~30 minutes. The index I, II and III depict the transition between vacuum to CO cylinder, CO cylinder to N2 cylinder and N2 cylinder to vacuum, respectively. (b) Oxygen partial pressure measured in vacuum, CO/N2, and ultra-high purity N2 flow. The spikes in transition I, II came from the transient pressure rises when switching the gas valves.
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Figure S6. Curve-fitted X-ray photoelectron Pt 4f spectra of the Pt-decorated β-Ga2O3 samples under different atmospheric treatments. (a) the as-received Pt-decorated βGa2O3 nanorod array; (b) following pure N2 treatment for 20 minutes at 500°C; (c) further treatment with pure O2 for 20 minutes at 500°C; (d) N2 treatment again for 20 minutes after oxygen treatment at 500°C; (e) treatment with CO for 20 minutes at 500°C as the last step.
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Figure S7. XPS Pt 4f7/2 binding energies of curve-fitted Pt 4f peak components (see Fig. S6) for particles decorating β-Ga2O3 after various gas treatments. Reference binding energies are shown for various Pt compounds.
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Figure S8. La0.8Sr0.2FeO3 thin film gas sensing characteristics. (a) Current-time characteristic of CO gas sensing test results tested under a bias of 1 V at 500°C with N2 as background atmosphere; lower bar chart shows the gas concentration of CO/N2;(b) Current-time characteristic of NO2 gas sensing test results tested under a bias of 1 V at 500°C with N2 as background atmosphere; lower bar graph shows the gas concentration of NO2/N2.
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Perovskite Nanoparticle-Sensitized Ga2O3 Nanorod Arrays for CO Detection at High Temperature Hui-Jan Lin,a John P. Baltrus,b Haiyong Gao,a Yong Ding,c Chang-Yong Nam,d Paul Ohodnicki, b, e Pu-Xian Gao a, * a
Department of Materials Science and Engineering & Institute of Materials Science, University of Connecticut, 97 North Eagleville Road, Storrs, Connecticut 06269-3136, United States b National Energy Technology Laboratory, 626 Cochrans Mill Road, Pittsburgh, Pennsylvania 15236, United States c School of Materials Science and Engineering, Georgia Institute of Technology, 771 Ferst Drive, Atlanta, Georgia 30332, United States d Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, United States e Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15216, United States *Corresponding author e-mail: [email protected]
S-1
(3)
(2) (1) (4)
Figure S1. Schematic illustration of a typical Ga2O3 nanorod array sensor testing setup, (1) Alumina holder, (2) Ga2O3-based nanorod array gas sensor fabricated on Si substrate, (3) ceramic screw and (4) platinum wires.
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(b)
Short Diagonal Length (nm)
Length (nm)
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Long Diagonal Length (nm) 400
400 300 200 100 0
(c)400 Length (nm)
Length (nm)
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300 200 100 0
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Length (nm)
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Ga2O3 Ga2O3
Ga2O3 LSFO/Ga2O3 Pt/Ga2O3
LSFO/Ga2O3 Pt/Ga2O3 Pt/Ga2O3 LSFO/Ga2O3 Short Diagonal Length (nm) 175.75 173.33 181.58
Long Diagonal Length (nm) 320.22 328.67 331
Individual Wire
Individual Wire
400 300 200 100 0
Individual Wire Short Diagonal Length S.D.(nm) 21.09 27.76 17.61
Long Diagonal Length S.D.(nm) 34.2 24.24 28.3
Figure S2. (a) Comparison of short and long diagonal lengths of the diamond shape tips of β-Ga2O3, LSFO/Ga2O3 and Pt/Ga2O3 nanorod arrays and the corresponding detail lengths of randomly picked nanorods are shown in (b), (c) and (d), respectively. (d) The table of the calculated short and long lengths of each type. The insert in (a) shows the diamond-shaped tip of a GaOOH nanorod.
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(a)
(b) Pt 3.39%
La0.8Sr0.2FeO3 0.61% Fe 37.93%
Ga2O3 96.61%
Ga2O3 99.39%
La 55.17%
6.90% Sr
Figure S3. The ICP-MS composition analyses results of (a) 3 wt. % Pt on Ga2O3 nanorod arrays, (b) 5 nm LSFO/Ga2O3 nanorod arrays.
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17.14.24 Acquire EDX Preview HAADF Point 1
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Ga-K
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Ga
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Figure S4. (a), (c), and (e) Typical HAADF STEM images of LSFO decorated β-Ga2O3 nanorods showing their porous structure; the corresponding EDS spectra from (b) point scanning, (d) and (e) line scanning revealing the existence and distribution of LSFO composition on β-Ga2O3 nanorods. The scale bar is 100 nm.
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(a)
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10
Carbon Monoxide Oxygen Nitrogen
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Carbon Monoxide Oxygen Nitrogen
2.34E-09 Pressure ( Torr )
10 Pressure ( Torr )
3x10
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II -8
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2x10
O2 in Vacuum
O2 in N2 Cylinder
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1.41E-09 Vacuum
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CO Cylind. N2 Cylind. Vac. 2000
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O2 in CO Cylinder
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CO Cylinder
N2 Cylinder N2 Cylinder
Vacuum_After Vacuum_After
Figure S5. Residual gas analysis of (a) dynamic partial pressure of CO, N2 and O2 in a sequence of vacuum in the Residual Gas Analyzer chamber, 2% CO balanced with N2 and ultra-high purity N2 cylinder, with each duration time of first three steps ~30 minutes. The index I, II and III depict the transition between vacuum to CO cylinder, CO cylinder to N2 cylinder and N2 cylinder to vacuum, respectively. (b) Oxygen partial pressure measured in vacuum, CO/N2, and ultra-high purity N2 flow. The spikes in transition I, II came from the transient pressure rises when switching the gas valves.
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Figure S6. Curve-fitted X-ray photoelectron Pt 4f spectra of the Pt-decorated β-Ga2O3 samples under different atmospheric treatments. (a) the as-received Pt-decorated βGa2O3 nanorod array; (b) following pure N2 treatment for 20 minutes at 500°C; (c) further treatment with pure O2 for 20 minutes at 500°C; (d) N2 treatment again for 20 minutes after oxygen treatment at 500°C; (e) treatment with CO for 20 minutes at 500°C as the last step.
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Figure S7. XPS Pt 4f7/2 binding energies of curve-fitted Pt 4f peak components (see Fig. S6) for particles decorating β-Ga2O3 after various gas treatments. Reference binding energies are shown for various Pt compounds.
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Figure S8. La0.8Sr0.2FeO3 thin film gas sensing characteristics. (a) Current-time characteristic of CO gas sensing test results tested under a bias of 1 V at 500°C with N2 as background atmosphere; lower bar chart shows the gas concentration of CO/N2;(b) Current-time characteristic of NO2 gas sensing test results tested under a bias of 1 V at 500°C with N2 as background atmosphere; lower bar graph shows the gas concentration of NO2/N2.
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