Supplementary Figures

Transcription

1 1635 Reflectance / a.u Supplementary Figures T-3 T-2 T Wavenumber / cm -1 Supplementary Figure 1 FTIR spectra of rutile TiO2 samples. Two bands at 1635 and 3425 cm -1 could be observed for all rutile TiO2 samples. The band at 1635 cm -1 is associated with the deformation vibrations for H-O-H bonds of physisorbed water while the band at 3425 cm -1 is due to bridging hydroxyls, which is obviously overlapped with the physisorbed water molecules.

2 Distribution / % Distribution / % Distribution / % Pt/T-1 Pt/T-2 Pt/T Cluster Size / nm Cluster Size / nm Cluster Size / nm Supplementary Figure 2 HAADF-STEM images of surface platinized rutile TiO2 samples and the size distribution of Pt nanoparticles.

3 PL intensity / a.u. T-1 T-2 T Wavelength / nm Supplementary Figure 3 Photoluminescence spectra of rutile TiO2 samples under study. No band gap photoluminescence can be observed since TiO2 is an indirect wide-gap semiconductor. Instead, two main emission signals at 480 nm and 580 nm are observed for all rutile TiO2 samples. The signal at 480 nm should be attributed to the recombination of free electrons at sub-bands below the conduction band and free holes at the valance band edge, while the signal at 580 nm can be attributed to electrons and holes recombination at oxygen vacancies and surface hydroxyl groups dominant sites. The similar positions of photoluminescence signals observed here indicate that the similar types of defects exist in rutile TiO2 samples under study.

4 Intensity / a.u Theta [deg.] Supplementary Figure 4 XRD pattern and TEM image of anatase TiO2 T-4.

5 Absorbance / a.u Wavelength / nm Supplementary Figure 5 Quasi in situ UV-vis spectra of anatase TiO2 during photocatalytic hydrogen production from water splitting under UV irradiation; Solid line: UV-Vis spectrum before irradiation; Dashed line: UV-Vis spectrum after UV irradiation for 5 min; Inset: Photograph of sample during photocatalytic reaction.

6 Supplementary Tables Supplementary Table 1 DFT characterized band information (ev) of rutile (110) with bridging hydroxyl (OHb), bridging oxygen vacancy (Ob-vac) and sub-surface oxygen vacancy (Osub-vac) System Defect Coverage Valence band top shift a Band gap b with neutral defect Band gap b with charged defect c Defect free e 3.1 e OHb Ob-vac Osub-vac d a : Reference state is the defect free surface; b : Gap between valence band top and band gap state or conduct band bottom in case band gap state overlaps with conduct band; c : No occupation in band gas states; d : Missing one O atom beneath the surface bridge O in first tri-tio2 layer e : System do not contain any defect

7 Supplementary Table 2 Band gap edges of rutile TiO2 samples under study Samples Conduction band bottom (ev vs. NHE) a Valence band top (ev vs. NHE) b Band gap (ev) c Band gap (ev) d T T T a : Measured by Mott Schottky plots; b : Measured by VB XPS; c : Valence band top subtracted by conduction band bottom; d : Measured by UV-Vis spectra

8 Supplementary Table 3 Comparison of photocatalytic activity in hydrogen production from water splitting over TiO2-based photocatalyst Photocatalyst Incident Reactant Co- H2 evolution rate light solution catalyst (μmolh -1 g -1 ) Ref. hydrogenated λ >400 nm 50 % % Pt H-TiO2 AM [1] hydrogenated λ >400 nm % titanate naotube AM 1.5 1% Pt 2150 TiO2 P25 AM [2] Al reduced 25 % λ >400 nm H-TiO2 1% Pt 12 [3] S doped H-TiO2 AM % 0.5% Pt 258 [4] Ti 3+ self-doped TiO2 λ >400 nm 25% 1% Pt 50 [5] Ti 3+ self-doped TiO2 λ >400 nm 25% 1% Pt 181 [6] vacuum activated TiO2 25% 0.38% λ >400 nm TiO2 P25 Pt 120 [7] TiO2 with oxygen λ >400 nm 25% 1% Pt 115 vacancies TiO2 P25 λ >400 nm 1% Pt 4 [8] Sub-10 nm rutile TiO2 λ >400 nm 10% 932 1% Pt nanoparticles AM hydrogenated λ >400 nm 10 % 107 This 1% Pt H-TiO2 a AM work TiO2 P25 λ >400 nm 10% 3 1% Pt AM a : prepared according to the procedures reported in ref. [1]

9 Supplementary References (1) Chen, X., Liu, L., Yu, P. Y. & Mao, S. S. Increasing solar absorption for photocatalysis with black hydrogenated titanium dioxide nanocrystals. Science 331, (2011). (2) Zheng, Z., Huang, B. & Lu, J. et al. Hydrogenated titania: synergy of surface modification and morphology improvement for enhanced photocatalytic activity. Chem. Commun. 48, (2012). (3) Wang, Z., Yang, C. & Lin, T. et al. Visible-light photocatalytic, solar thermal and photoelectrochemical properties of aluminium-reduced black titania. Energy. Environ. Sci. 6, (2013). (4) Yang, C., Wang, Z. & Lin, T. et al. Core-shell nanostructured Black rutile titania as excellent catalyst for hydrogen production enhanced by sulfur doping. J. Am. Chem. Soc. 135, (2013). (5) Zuo, F., Wang, L. & Wu, T. et al. Self-doped Ti 3+ enhanced photocatalyst for hydrogen production under visible light. J. Am. Chem. Soc. 132, (2010). (6) Zuo, F., Bozhilov, K. & Dillon, R. J. et al. Active facets on titanium (III) doped TiO2: an effective strategy to improve the visible light photocatalytic activity. Angew. Chem. Int. Ed. 124, (2012). (7) Xing, M., Zhang, J., Chen, F. & Tian, B. An economic method to prepare vacuum activated photocatalysts with high photo-activities and photosensitivities. Chem.

10 Commun. 47, (2011). (8) Zou, X., Liu, J. & Su, J. et al. Facile synthesis of thermal- and photostable titania with paramagnetic oxygen vacancies for visible-light photocatalysis. Chem. Eur. J. 19, (2013).