Ordered Mesoporous Black TiO2 as Highly Efficient Hydrogen ...
Supporting Information
Ordered Mesoporous Black TiO2 as Highly Efficient Hydrogen Evolution Photocatalyst Wei Zhou,†,‡ Wei Li,§,‡ Jianqiang Wang,# Yang Qu,† Ying Yang,† Ying Xie,† Kaifu Zhang,† Lei Wang,† Honggang Fu*,† and Dongyuan Zhao*,§
†
Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education
of the People's Republic of China, Heilongjiang University, Harbin 150080, P. R. China. §
Department of Chemistry, Laboratory of Advanced Materials, Shanghai Key Lab of
Molecular Catalysis and Innovative Materials, and State key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai 200433, P. R. China. #
Shanghai Synchrotron Radiation Facility (SSRF), Shanghai Institute of Applied
Physics, Chinese Academy of Sciences, Shanghai 201204, P. R. China.
Email: [email protected], [email protected]
S1
Experimental Section Chemicals. Tetrabutyl titanate (TBOT), ethanol, concentrated hydrochloric acid and ethylenediamine were of analytical grade and purchased from Shanghai Chemical Corp.
Triblock
copolymer,
HO(CH2CH2O)20(CH2CH(CH3)O)70(CH2CH2O)20H
(EO20PO70EO20, Pluronic P123, MW=5800, Product No. 435465-1L) was purchased from Aldrich. All chemicals were used as received without further purification. Deionized water was used for all experiments. Preparation of ordered mesoporous black TiO2 (OMBT). The ordered mesoporous black TiO2 materials were fabricated via an evaporation-induced self-assembly method combined with an ethylenediamine encircling process, followed by hydrogenation. Typically, 1.0 g of triblock copolymer Pluronic P123 was dissolved in 15 mL of anhydrous ethanol (EtOH), stirred for 0.5 h at room temperature and then sonicated for 10 min. Meanwhile, 3.2 mL of concentrated hydrochloric acid was slowly added to 4.0 g of TBOT solution dropwise. After magnetic stirring for 0.5 h, the mixture of P123/EtOH was added to the above solution with vigorous stirring for at least 3 h. The resulting sol solution was gelled in an open petri dish at room temperature and 50–60% relative humidity (RH) for several weeks. Then, the as-prepared powders were calcined at 200 °C for 4 h in order to stabilize the network. Subsequently, the products were refluxed with ethylenediamine aqueous solution for 48 h at 90-100 °C. The pH value was kept at 11-12. Then, the obtained powders were washed by deionized water and dried at 60 °C overnight. Finally, the resulting
S2
samples were first calcined at 350 °C under N2 atmosphere for 3 h to stabilize the mesostructure network and then calcined at 700 °C in air for 2 h to remove the organic template and improve crystallinity (denoted as OMT). After cooling down to 200 °C, it was deaerated under inert gas flow (N2) for 0.5 h, subsequently, calcined in H2 flow at 500 °C for 3 h under normal pressure conditions, with a constant heating rate of 5 °C min-1. The H2 flow was remained constant until cooling to room temperature. The resultant black powders were denoted as OMBT. Preparation of porous gray TiO2 by normal process without the ethylenediamine encircling process. Typically, 1.0 g of Pluronic P123 was dissolved in 15 mL of EtOH, stirred for 0.5 h at room temperature and then sonicated for 10 min. Meanwhile, 3.2 mL of concentrated hydrochloric acid was slowly added to 4.0 g of TBOT solution dropwise. After magnetic stirring for 0.5 h, the mixture of P123/EtOH was added to the above solution with vigorous stirring for at least 3 h. The resulting sol solution was gelled in an open petri dish at room temperatureand and 50–60% RH for several weeks. Then, the as-prepared powders were calcined at 500 °C in air for 4 h to remove the organic template and improve crystallinity. After cooling down to room temperature, they were subsequently calcined in H2 flow at 500 °C for 3 h under normal pressure conditions, with a constant heating rate of 5 °C min-1. The H2 flow was remained constant until cooling to room temperature. Preparation of porous black TiO2 by direct hydrogenation from the as-made TiO2-surfactant mesophase. Typically, 1.0 g of P123 was dissolved in 15 mL of EtOH, stirred for 0.5 h at room temperature and then sonicated for 10 min. Meanwhile, S3
3.2 mL of concentrated hydrochloric acid was slowly added to 4.0 g of TBOT solution dropwise. After magnetic stirring for 0.5 h, the mixture of P123/EtOH was added to the above solution with vigorous stirring for at least 3 h. The resulting sol solution was gelled in an open petri dish at room temperature and and 50–60% RH for several weeks. Then, the as-prepared powders were calcined in H2 flow at 500 °C for 3 h under normal pressure conditions, with a constant heating rate of 5 °C min-1. The H2 flow was remained constant until cooling to room temperature. Characterizations. Low-angle X-ray diffraction (XRD) patterns were obtained on a Siemens D5005 diffractometer with Cu Kα radiation (λ = 1.5406 Å). Wide-angle X-ray diffraction (XRD) patterns were obtained by a Bruker D8 Advance diffractometer by using Cu Kα radiation (λ = 1.5406 Å, 40 kV, 40 mA). The scan rate and the step size were 6 °/min and 0.02 °, respectively. Raman measurements were performed with a Jobin Yvon HR 800 micro-Raman spectrometer at 457.9 nm. The laser beam was focused with a 50 × objective lens to a ca. 1 µm spot on the surface of the sample. The transmission electron microscopy (TEM) experiments were performed on a JEOL JEM-2100 F microscope (Japan) operated at 200 kV. Carbon-coated coppergrids were used as the sample holders. X-ray photoelectron spectroscopy (XPS, Kratos, ULTRA AXIS DLD) was carried out with monochrome Al Kα (hν = 1486.6 eV) radiation. All binding energies were calibrated by referencing to C1s peak at 284.6 eV. The deconvolution of the O peaks was performed through a software XPSPEAK version 4.1. Diffuse reflectance spectroscopy (DRS) was measured on a UV/vis S4
spectrophotometer (Shimadzu UV-2550) in the range of 200 – 1300 nm. The band gaps were estimated by extrapolating a linear part of the plots to (αhν)2 = 0. Nitrogen adsorption-desorption isotherms at 77 K were collected on an AUTOSORB-1 (Quantachrome Instruments) nitrogen adsorption apparatus. All of the samples were degassed under vacuum at 180 °C for at least 8 h prior to measurement. The Brunauer−Emmett−Teller (BET) equation was used to calculate the specific surface area. Pore size distributions were obtained using the Barrett−Joyner−Halenda (BJH) method from the adsorption branch of the isotherms. The surface photovoltage spectroscopy (SPS) measurements were carried out with a home-built apparatus equipped with a lock-in amplifier (SR830) synchronized with a light chopper (SR540). The powders were sandwiched between two indium tin oxide (ITO)-coated glass electrodes, and monochromatic light was passed from a 500 W xenon lamp through a double prism monochromator (SBP300). Transient-state surface photovoltage (TS-SPV) measurement was performed with a self-assembled device in air atmosphere at room temperature. The powders were excited by a 532 nm-laser radiation with 10 ns pulse width from a second harmonic Nd:YAG laser (Lab-130-10H, Newport, Co.). The signals were collected via a 1 GHz digital phosphor oscilloscope (DPO 4104B, Tektronix) with a pre-amplier. X-ray absorption fine structure (XAFS) spectroscopy was performed at room temperature intransmission mode on beam-line BL14W1 of the Shanghai Synchrotron Radiation Facility (SSRF), China. The station was operated with a Si (111) double-crystal monochromator. The synchrotron was operated at energy of 3.5 GeV and the current S5
in the range 150-210 mA. The photon energy was calibrated with Ag foil. Data processing was performed by the program ATHENA. The beam-line covered the energy range from 100 to 1000 eV, with an energy resolution of 0.2 eV. Photocatalytic
hydrogen evolution.
The
photocatalytic
hydrogen
evolution
experiments were conducted in an online photocatalytic hydrogen generation system (AuLight, Beijing, CEL-SPH2N) at ambient temperature (20 °C). Photocatalyst (100 mg) loaded with Pt (1 wt.%) was suspended in a mixture of 80 mL of water and 20 mL of methanol in closed-gas circulation reaction cell by using a magnetic stirrer. Prior to the reaction, the mixture was deaerated by evacuation to remove O2 and CO2 dissolved in water. An AM 1.5 solar power system (solar simulator (Oriel, USA) equipped with an AM 1.5G filter (Oriel, USA)) was used as light irradiation source. Gas evolution was observed only under photoirradiation with a power density of 100 mW/cm2, being analyzed by an on-line gas chromatograph (SP7800, TCD, molecular sieve 5 Å, N2 carrier, Beijing Keruida Limited). The hydrogen evolution value is calculated based on 100 mg of the catalyst. The determination of the apparent quantum efficiency for hydrogen generation was performed using the same closed circulating system under illumination of a 300 W Xe lamp with bandpass filter (365, 420 and 520 nm) system. Once the photocatalytic reaction of a testing cycle in 3 h was complete, the reactor was replenished with 1 mL of methanol and degassed in vacuum before starting the subsequent cycle. Photoelectrochemical property. The photoelectrochemical properties in this study were carried out using a Princeton Versa STAT 3 in a standard three electrode S6
configurations with OMT and OMBT materials used as photoanodes, Pt foil as counter electrode, and Ag/AgCl electrode as the reference electrode. 0.1 M NaOH purged with N2 was used as the electrolyte. An AM 1.5 solar power system was used as light irradiation source. The photoanodes were prepared by doctor-blade method, using a glass rod to roll a paste containing 0.2 g of powder and 0.5 mL of EtOH on transparent conducting glass (TCO, fluorine doped SnO2 layer, 20 Ω/square, Nippon sheet glass, Japan), and pressed at 1000 kg cm-2 between stainless-steel plates in a hydraulic press using aluminium foil to prevent adhesion to form a film (2 × 1 cm).
S7
Figure S1. X-ray diffraction patterns (A) and the photos (B) of the ordered mesoporous black TiO2 materials (a) and ordered mesoporous TiO2 materials (b).
Figure S2. Raman spectra of the ordered mesoporous black TiO2 materials (a) and ordered mesoporous TiO2 materials (b).
S8
Figure S3. The low-angle XRD patterns of OMT (a), OMBT (b), mesoporous TiO2 without the treatment of ethylenediamine (c), and porous black titania made by hydrogenation of the as-synthesized titania-surfactant mesophase (d).
Figure S4. The transmission electron microscopy (A) and the corresponding selected-area electron diffraction pattern images (B) of the ordered mesoporous black TiO2 materials.
S9
Figure S5. N2 adsorption-desorption isotherms (A) and the corresponding pore size distribution plots (B) of the ordered mesoporous black TiO2 materials (a) and ordered mesoporous TiO2 materials (b).
Figure S6. The ultraviolet-visible absorption spectra (A) and optical bandgaps (B) of the ordered mesoporous black TiO2 materials (a) and ordered mesoporous TiO2 materials (b).
S10
Figure S7. The Ti 2p (A), O 1s (B) and valence band X-ray photoelectron spectra (C) of the ordered mesoporous black TiO2 materials (a) and ordered mesoporous TiO2 materials (b).
Figure S8. The transmission electron microscopy (A), X-ray diffraction pattern (B), N2 adsorption-desorption isotherm (C) and the corresponding pore size distribution plot (D) of the mesoporous TiO2 prepared by direct calcination without ethylenediamine protecting.
S11
Figure S9. The transmission electron microscopy (A), X-ray diffraction pattern (B), N2 adsorption-desorption isotherm (C) and the corresponding pore size distribution plot (D) of the porous gray TiO2 prepared by a normal process without ethylenediamine protecting. The inset of (B) is the photo of porous gray TiO2 sample.
Figure S10. The transmission electron microscopy image (A), X-ray diffraction pattern (B), N2 adsorption-desorption isotherms (C) and the corresponding pore size distribution plot (D) of the black TiO2 preprared by direct hydrogenation of the amorphous TiO2-surfactant mesophase. The inset of (B) is the photo of the black TiO2 sample.
S12
Figure S11. The UV-vis spectra of solar simulator equipped with an AM 1.5G filter.
Figure S12. The H2 generation rate of OMBT (a, c) and OMT (b, d) without Pt as a co-catalyst and in pure water system, respectively.
S13
Figure S13. Surface photovoltage spectroscopy (A) and transient-state surface photovoltage spectra (B) of the ordered mesoporous black TiO2 materials (a) and ordered mesoporous TiO2 (b) materials.
S14
Table S1. The textual properties of the resultant TiO2 materials.
Brunauer−Emmett−Teller Samples
Pore size (nm)
3
-1
Pore volume (cm g ) surface area (m2 g-1)
Ordered mesoporous TiO2
9.9
0.23
122
Ordered mesoporous black TiO2
9.6
0.24
124
Black TiO2 by direct hydrogenation
19.8
0.25
62
Mesoporous TiO2 by direct calcination
19.2
0.28
71
Gray TiO2 by a normal process
25.8
0.21
68
S15
Table S2. Local structural parameters in the Ti extended X-ray absorption fine structure of ordered mesoporous black TiO2 and ordered mesoporous TiO2 materials. (S02=0.73)
Samples
Ordered mesoporous black TiO2
Ordered mesoporous TiO2
Shell
N
a)
b)
Rj [Å]
2 c)
σ
-3
2
[×10 Å ]
5.3 (±1.8)
d)
∆E0 [eV]
Ti-O
3.8 (±0.5)
1.970 (±0.006)
Ti-Ti
0.3 (±0.3)
2.71 (±0.09)
7.0
2.1
Ti-Ti
2.0 (±0.4)
3.04 (±0.02)
6.0
-7.6
Ti-O
1.5
3.64 (±0.08)
4.0
-11.0
Ti-Ti
3.0
3.90 (±0.03)
10.1(±4.2)
-7.8
Ti-O
3.7 (±0.4)
1.971 (±0.005)
3.6 (±1.2)
1.0
Ti-Ti
2.5
3.029 (±0.006)
Ti-Ti
4.0
3.87 (±0.01)
3.0 (±0.7) 7.6 (±1.7)
0.67
-8.8 -10.0
a) Coordination number. b) Distance between the absorbing and back-scattering atoms. c) Debye-Waller factor. d) Inner potential correction.
S16
Ordered Mesoporous Black TiO2 as Highly Efficient Hydrogen Evolution Photocatalyst Wei Zhou,†,‡ Wei Li,§,‡ Jianqiang Wang,# Yang Qu,† Ying Yang,† Ying Xie,† Kaifu Zhang,† Lei Wang,† Honggang Fu*,† and Dongyuan Zhao*,§
†
Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education
of the People's Republic of China, Heilongjiang University, Harbin 150080, P. R. China. §
Department of Chemistry, Laboratory of Advanced Materials, Shanghai Key Lab of
Molecular Catalysis and Innovative Materials, and State key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai 200433, P. R. China. #
Shanghai Synchrotron Radiation Facility (SSRF), Shanghai Institute of Applied
Physics, Chinese Academy of Sciences, Shanghai 201204, P. R. China.
Email: [email protected], [email protected]
S1
Experimental Section Chemicals. Tetrabutyl titanate (TBOT), ethanol, concentrated hydrochloric acid and ethylenediamine were of analytical grade and purchased from Shanghai Chemical Corp.
Triblock
copolymer,
HO(CH2CH2O)20(CH2CH(CH3)O)70(CH2CH2O)20H
(EO20PO70EO20, Pluronic P123, MW=5800, Product No. 435465-1L) was purchased from Aldrich. All chemicals were used as received without further purification. Deionized water was used for all experiments. Preparation of ordered mesoporous black TiO2 (OMBT). The ordered mesoporous black TiO2 materials were fabricated via an evaporation-induced self-assembly method combined with an ethylenediamine encircling process, followed by hydrogenation. Typically, 1.0 g of triblock copolymer Pluronic P123 was dissolved in 15 mL of anhydrous ethanol (EtOH), stirred for 0.5 h at room temperature and then sonicated for 10 min. Meanwhile, 3.2 mL of concentrated hydrochloric acid was slowly added to 4.0 g of TBOT solution dropwise. After magnetic stirring for 0.5 h, the mixture of P123/EtOH was added to the above solution with vigorous stirring for at least 3 h. The resulting sol solution was gelled in an open petri dish at room temperature and 50–60% relative humidity (RH) for several weeks. Then, the as-prepared powders were calcined at 200 °C for 4 h in order to stabilize the network. Subsequently, the products were refluxed with ethylenediamine aqueous solution for 48 h at 90-100 °C. The pH value was kept at 11-12. Then, the obtained powders were washed by deionized water and dried at 60 °C overnight. Finally, the resulting
S2
samples were first calcined at 350 °C under N2 atmosphere for 3 h to stabilize the mesostructure network and then calcined at 700 °C in air for 2 h to remove the organic template and improve crystallinity (denoted as OMT). After cooling down to 200 °C, it was deaerated under inert gas flow (N2) for 0.5 h, subsequently, calcined in H2 flow at 500 °C for 3 h under normal pressure conditions, with a constant heating rate of 5 °C min-1. The H2 flow was remained constant until cooling to room temperature. The resultant black powders were denoted as OMBT. Preparation of porous gray TiO2 by normal process without the ethylenediamine encircling process. Typically, 1.0 g of Pluronic P123 was dissolved in 15 mL of EtOH, stirred for 0.5 h at room temperature and then sonicated for 10 min. Meanwhile, 3.2 mL of concentrated hydrochloric acid was slowly added to 4.0 g of TBOT solution dropwise. After magnetic stirring for 0.5 h, the mixture of P123/EtOH was added to the above solution with vigorous stirring for at least 3 h. The resulting sol solution was gelled in an open petri dish at room temperatureand and 50–60% RH for several weeks. Then, the as-prepared powders were calcined at 500 °C in air for 4 h to remove the organic template and improve crystallinity. After cooling down to room temperature, they were subsequently calcined in H2 flow at 500 °C for 3 h under normal pressure conditions, with a constant heating rate of 5 °C min-1. The H2 flow was remained constant until cooling to room temperature. Preparation of porous black TiO2 by direct hydrogenation from the as-made TiO2-surfactant mesophase. Typically, 1.0 g of P123 was dissolved in 15 mL of EtOH, stirred for 0.5 h at room temperature and then sonicated for 10 min. Meanwhile, S3
3.2 mL of concentrated hydrochloric acid was slowly added to 4.0 g of TBOT solution dropwise. After magnetic stirring for 0.5 h, the mixture of P123/EtOH was added to the above solution with vigorous stirring for at least 3 h. The resulting sol solution was gelled in an open petri dish at room temperature and and 50–60% RH for several weeks. Then, the as-prepared powders were calcined in H2 flow at 500 °C for 3 h under normal pressure conditions, with a constant heating rate of 5 °C min-1. The H2 flow was remained constant until cooling to room temperature. Characterizations. Low-angle X-ray diffraction (XRD) patterns were obtained on a Siemens D5005 diffractometer with Cu Kα radiation (λ = 1.5406 Å). Wide-angle X-ray diffraction (XRD) patterns were obtained by a Bruker D8 Advance diffractometer by using Cu Kα radiation (λ = 1.5406 Å, 40 kV, 40 mA). The scan rate and the step size were 6 °/min and 0.02 °, respectively. Raman measurements were performed with a Jobin Yvon HR 800 micro-Raman spectrometer at 457.9 nm. The laser beam was focused with a 50 × objective lens to a ca. 1 µm spot on the surface of the sample. The transmission electron microscopy (TEM) experiments were performed on a JEOL JEM-2100 F microscope (Japan) operated at 200 kV. Carbon-coated coppergrids were used as the sample holders. X-ray photoelectron spectroscopy (XPS, Kratos, ULTRA AXIS DLD) was carried out with monochrome Al Kα (hν = 1486.6 eV) radiation. All binding energies were calibrated by referencing to C1s peak at 284.6 eV. The deconvolution of the O peaks was performed through a software XPSPEAK version 4.1. Diffuse reflectance spectroscopy (DRS) was measured on a UV/vis S4
spectrophotometer (Shimadzu UV-2550) in the range of 200 – 1300 nm. The band gaps were estimated by extrapolating a linear part of the plots to (αhν)2 = 0. Nitrogen adsorption-desorption isotherms at 77 K were collected on an AUTOSORB-1 (Quantachrome Instruments) nitrogen adsorption apparatus. All of the samples were degassed under vacuum at 180 °C for at least 8 h prior to measurement. The Brunauer−Emmett−Teller (BET) equation was used to calculate the specific surface area. Pore size distributions were obtained using the Barrett−Joyner−Halenda (BJH) method from the adsorption branch of the isotherms. The surface photovoltage spectroscopy (SPS) measurements were carried out with a home-built apparatus equipped with a lock-in amplifier (SR830) synchronized with a light chopper (SR540). The powders were sandwiched between two indium tin oxide (ITO)-coated glass electrodes, and monochromatic light was passed from a 500 W xenon lamp through a double prism monochromator (SBP300). Transient-state surface photovoltage (TS-SPV) measurement was performed with a self-assembled device in air atmosphere at room temperature. The powders were excited by a 532 nm-laser radiation with 10 ns pulse width from a second harmonic Nd:YAG laser (Lab-130-10H, Newport, Co.). The signals were collected via a 1 GHz digital phosphor oscilloscope (DPO 4104B, Tektronix) with a pre-amplier. X-ray absorption fine structure (XAFS) spectroscopy was performed at room temperature intransmission mode on beam-line BL14W1 of the Shanghai Synchrotron Radiation Facility (SSRF), China. The station was operated with a Si (111) double-crystal monochromator. The synchrotron was operated at energy of 3.5 GeV and the current S5
in the range 150-210 mA. The photon energy was calibrated with Ag foil. Data processing was performed by the program ATHENA. The beam-line covered the energy range from 100 to 1000 eV, with an energy resolution of 0.2 eV. Photocatalytic
hydrogen evolution.
The
photocatalytic
hydrogen
evolution
experiments were conducted in an online photocatalytic hydrogen generation system (AuLight, Beijing, CEL-SPH2N) at ambient temperature (20 °C). Photocatalyst (100 mg) loaded with Pt (1 wt.%) was suspended in a mixture of 80 mL of water and 20 mL of methanol in closed-gas circulation reaction cell by using a magnetic stirrer. Prior to the reaction, the mixture was deaerated by evacuation to remove O2 and CO2 dissolved in water. An AM 1.5 solar power system (solar simulator (Oriel, USA) equipped with an AM 1.5G filter (Oriel, USA)) was used as light irradiation source. Gas evolution was observed only under photoirradiation with a power density of 100 mW/cm2, being analyzed by an on-line gas chromatograph (SP7800, TCD, molecular sieve 5 Å, N2 carrier, Beijing Keruida Limited). The hydrogen evolution value is calculated based on 100 mg of the catalyst. The determination of the apparent quantum efficiency for hydrogen generation was performed using the same closed circulating system under illumination of a 300 W Xe lamp with bandpass filter (365, 420 and 520 nm) system. Once the photocatalytic reaction of a testing cycle in 3 h was complete, the reactor was replenished with 1 mL of methanol and degassed in vacuum before starting the subsequent cycle. Photoelectrochemical property. The photoelectrochemical properties in this study were carried out using a Princeton Versa STAT 3 in a standard three electrode S6
configurations with OMT and OMBT materials used as photoanodes, Pt foil as counter electrode, and Ag/AgCl electrode as the reference electrode. 0.1 M NaOH purged with N2 was used as the electrolyte. An AM 1.5 solar power system was used as light irradiation source. The photoanodes were prepared by doctor-blade method, using a glass rod to roll a paste containing 0.2 g of powder and 0.5 mL of EtOH on transparent conducting glass (TCO, fluorine doped SnO2 layer, 20 Ω/square, Nippon sheet glass, Japan), and pressed at 1000 kg cm-2 between stainless-steel plates in a hydraulic press using aluminium foil to prevent adhesion to form a film (2 × 1 cm).
S7
Figure S1. X-ray diffraction patterns (A) and the photos (B) of the ordered mesoporous black TiO2 materials (a) and ordered mesoporous TiO2 materials (b).
Figure S2. Raman spectra of the ordered mesoporous black TiO2 materials (a) and ordered mesoporous TiO2 materials (b).
S8
Figure S3. The low-angle XRD patterns of OMT (a), OMBT (b), mesoporous TiO2 without the treatment of ethylenediamine (c), and porous black titania made by hydrogenation of the as-synthesized titania-surfactant mesophase (d).
Figure S4. The transmission electron microscopy (A) and the corresponding selected-area electron diffraction pattern images (B) of the ordered mesoporous black TiO2 materials.
S9
Figure S5. N2 adsorption-desorption isotherms (A) and the corresponding pore size distribution plots (B) of the ordered mesoporous black TiO2 materials (a) and ordered mesoporous TiO2 materials (b).
Figure S6. The ultraviolet-visible absorption spectra (A) and optical bandgaps (B) of the ordered mesoporous black TiO2 materials (a) and ordered mesoporous TiO2 materials (b).
S10
Figure S7. The Ti 2p (A), O 1s (B) and valence band X-ray photoelectron spectra (C) of the ordered mesoporous black TiO2 materials (a) and ordered mesoporous TiO2 materials (b).
Figure S8. The transmission electron microscopy (A), X-ray diffraction pattern (B), N2 adsorption-desorption isotherm (C) and the corresponding pore size distribution plot (D) of the mesoporous TiO2 prepared by direct calcination without ethylenediamine protecting.
S11
Figure S9. The transmission electron microscopy (A), X-ray diffraction pattern (B), N2 adsorption-desorption isotherm (C) and the corresponding pore size distribution plot (D) of the porous gray TiO2 prepared by a normal process without ethylenediamine protecting. The inset of (B) is the photo of porous gray TiO2 sample.
Figure S10. The transmission electron microscopy image (A), X-ray diffraction pattern (B), N2 adsorption-desorption isotherms (C) and the corresponding pore size distribution plot (D) of the black TiO2 preprared by direct hydrogenation of the amorphous TiO2-surfactant mesophase. The inset of (B) is the photo of the black TiO2 sample.
S12
Figure S11. The UV-vis spectra of solar simulator equipped with an AM 1.5G filter.
Figure S12. The H2 generation rate of OMBT (a, c) and OMT (b, d) without Pt as a co-catalyst and in pure water system, respectively.
S13
Figure S13. Surface photovoltage spectroscopy (A) and transient-state surface photovoltage spectra (B) of the ordered mesoporous black TiO2 materials (a) and ordered mesoporous TiO2 (b) materials.
S14
Table S1. The textual properties of the resultant TiO2 materials.
Brunauer−Emmett−Teller Samples
Pore size (nm)
3
-1
Pore volume (cm g ) surface area (m2 g-1)
Ordered mesoporous TiO2
9.9
0.23
122
Ordered mesoporous black TiO2
9.6
0.24
124
Black TiO2 by direct hydrogenation
19.8
0.25
62
Mesoporous TiO2 by direct calcination
19.2
0.28
71
Gray TiO2 by a normal process
25.8
0.21
68
S15
Table S2. Local structural parameters in the Ti extended X-ray absorption fine structure of ordered mesoporous black TiO2 and ordered mesoporous TiO2 materials. (S02=0.73)
Samples
Ordered mesoporous black TiO2
Ordered mesoporous TiO2
Shell
N
a)
b)
Rj [Å]
2 c)
σ
-3
2
[×10 Å ]
5.3 (±1.8)
d)
∆E0 [eV]
Ti-O
3.8 (±0.5)
1.970 (±0.006)
Ti-Ti
0.3 (±0.3)
2.71 (±0.09)
7.0
2.1
Ti-Ti
2.0 (±0.4)
3.04 (±0.02)
6.0
-7.6
Ti-O
1.5
3.64 (±0.08)
4.0
-11.0
Ti-Ti
3.0
3.90 (±0.03)
10.1(±4.2)
-7.8
Ti-O
3.7 (±0.4)
1.971 (±0.005)
3.6 (±1.2)
1.0
Ti-Ti
2.5
3.029 (±0.006)
Ti-Ti
4.0
3.87 (±0.01)
3.0 (±0.7) 7.6 (±1.7)
0.67
-8.8 -10.0
a) Coordination number. b) Distance between the absorbing and back-scattering atoms. c) Debye-Waller factor. d) Inner potential correction.
S16
