Supporting Information

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1 Supporting Information Hydrogenated Blue Titania for Efficient Solar to Chemical Conversions: Preparation, Characterization, and Reaction Mechanism of CO2 Reduction Guoheng Yin,, Xieyi Huang, Tianyuan Chen, Wei Zhao, Qingyuan Bi, *, Jing Xu, Yifan Han, *, and Fuqiang Huang *,, State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai , People s Republic of China University of Chinese Academy of Sciences, Beijing , People s Republic of China State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai , People s Republic of China Beijing National Laboratory for Molecular Sciences and State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing , People s Republic of China *Corresponding Authors * for Q.B.: biqingyuan@mail.sic.ac.cn. * for Y.H.: yifanhan@ecust.edu.cn. * for F.H.: huangfq@mail.sic.ac.cn. S1

2 Table S1. Phase compositions of pristine and H x samples. Phase H x H x H x H x H x H x (wt%) (P25) (0) (50) (100) (200) (300) (400) Anatase Rutile The ratios of the rutile phase in the pristine and H x were calculated by a normalized RIR (Reference Intensity Ratio, IR(110)/IA(101)) method. H--x (400) H--x (300) H--x (0) Theta ( ) Figure S1. XRD patterns of pristine and H x samples. S2

3 Figure S2. XRD patterns of pristine (rutile) and H R x. It is emphasized that the yield of H R x is more than 90 wt% of pristine (rutile) in spite of the sharply decreased diffraction peaks. Therefore, the reduced rutile phase was disordered rather than dissolved in solvent. Figure S3. XRD patterns of pristine (anatase) and H A x. It is emphasized that the H A x is still highly crystallized after solvothermal treatment. S3

4 Figure S4. Photographs of (a) H x(200), (b) H R x, and (c) H A x. (a) (b) 3.50 Å (101) 5 nm 3.50 Å (101) 5 nm Figure S5. HRTEM images of (a) H R x and (b) H A x. Note that the H R x is highly disordered while the H A x is still highly crystallized. Figure S6. (a) XPS Ti 2p and (b) XPS Li 2s spectra of pristine and H x samples. XPS Li 2s spectra (b) indicate that there is no existence of Li element in the attained blue titania and the ICP measurements also show that only less than wt% of Li in H x samples. The slight shift to lower energies in XPS Ti 2p of H x (a) indicates the formation of some surface Ti S4

5 (a) (b) H--x (50) 50 nm 50 nm (c) (d) H--x (100) H--x (200) 50 nm 50 nm Figure S7. TEM images of (a) pristine, (b) H x(50), (c) H x(100), and (d) H x(200). H--x (0) 5 nm Figure S8. HRTEM image of H x(0). S5

6 Figure S9. (a) TEM and (b) HRTEM images of H x(300). Eg (a) H--x (0) EPR H--x (200) H--x (0) (b) Raman shift (cm -1 ) g value Figure S10. (a) Raman and (b) EPR spectra of H x(0). Data of pristine and H x(200) are as comparison. S6

7 O 1s H- (200) H- (100) H- (50) Binding energy (ev) Figure S11. XPS O 1s spectra of pristine and H x samples. The peaks at and ev are attributed to Ti O and Ti OH bond, respectively. The Ti OH peak intensity of H x samples is stronger than that of pristine. Defective oxygen sites could tend to bind with hydrogen atoms and then locally form surface hydroxyl groups. 2 Figure S12. PL spectra of pristine and H x samples. In order to reveal the behavior of light-excited electrons and holes, we carried out the photoluminescence (PL) emission measurement since PL spectra can precisely reflect the efficiency of the free carrier trapping, migration, transfer, and separation in semiconductors. The PL spectra (excited at 320 nm) of and H x in the wavelength range of nm are shown in Figure S12. The PL peak intensity of S7

8 H x is much less than that of the pristine, which indicates that H x has a much lower recombination rate of electrons and holes under light irradiation. In addition, the generated defects (doped H or oxygen vacancy) and the consequent intermediate states highly improve the conductivity and carrier density of H x, which efficiently accelerates the transfer and separation of light-generated carriers, so abundant electrons can reach the surface of nanoparticles and participate in the photocatalytic reactions. Light Irradiation Quartz Window Catalyst Deionized water Figure S. Schematic diagram of the reactor for photocatalytic reduction of CO 2 with moisture. Table S2. Comparison of photocatalytic activity of CO 2 reduction over -based catalysts. Catalyst P25 with {001} and {101} facets Reaction conditions 200 W Xe lamp, UV-Vis (λ = 320 ~ 780 nm), 2 bar 300 W Xe lamp, ambient temperature, atmospheric pressure STY of CH 4 (μmol g 1 h 1 ) By-product 1.2 CO, H powder 75 W Hg lamp, λ > 280 nm 0.02 C 2H 4, C 2H 6 5 Anatase particles 990 W Xe lamp, 0.96 KW m 2, 90 bar Reference S8

9 Ti-PS (Si/Ti = 50, hexagonal) Extracted 100 W Hg lamp, UV irradiation, 323 K UV 8 W Hg lamp, λ = 254 nm, supercritical fluid-grade CO CH 3OH 7 ~ Ti-beta(OH) 100 W Hg lamp, λ > 250 nm 5.8 CH 3OH 9 14 nm anatase particles P25 particles pellets P25 particles Self-doped Ti 3+ -rutile Black films Ti 3+ -self doped brookite Reduced {001}- x H- x 8 W Hg lamp, λ = 254 nm, CH 3OH, H 2, 0.4 supercritical fluid-grade CO 2 CO W UV or near-uv lamp, λ = 365 or 254 nm, 316 K 4.11 CO, C 2H 6 11 Three germicidal UVC lamps, λ = nm 0.22 (μmol h 1 ) H 2, CO W Xe lamp, λ < 700 nm, 343 K 0.1 H 2, CO 300 W Xe lamp, Vis-light, 1 atm < Simulated sunlight, room temperature, continuous CO CO W Xe lamp, Vis-light, continuous CO CO W Xe lamp, AM1.5 < 0.3 CO W Xe lamp, simulated solar, 2 bar 16.2 H 2, CO this work VB H- (200) H- (100) H- (50) Binding energy (ev) Figure S14. XPS VB spectra of pristine and H x samples. After solvothermal treatment, the valance band edge of H x samples shows a red shift, or even gains a band tail. S9

10 Table S3. O 2 formation of CO 2 photoreduction over pristine and H x with different light sources. a Light source Catalyst Concentration (ppm) STY of O 2 formation b Air residuals (N 2 + O 2) c Generated O 2 d Measured Theoretical e Solar- light H x(50) H x(100) H x(200) H x(300) Vis- light H x(50) H x(100) H x(200) H x(300) a Reaction conditions: 50 mg cat., 2 bar CO 2, 6 ml H 2O, 5 h. b The unit of STY is μmol g 1 h 1. c The concentration of air residuals (N 2 + O 2) was tested before light irradiation in each experiment. d The concentration of generated O 2 was obtained by subtracting the concentration of the air residuals. e The theoretical rate of O 2 formation was calculated by (O 2 formation rate) = [(H 2 formation rate)/2 + (CO formation rate)/2 + 2 (CH 4 formation rate)]. Figure S15. Recycling of H x(200) catalyst for CH 4 formation via photoreduction of CO 2. Reaction conditions: 50 mg catalyst, 2 bar CO 2, 6 ml H 2O, full solar irradiation, 5 h in each run. S10

11 Figure S16. (a) TEM and (b) HRTEM images of the used H x(200). Used H--x (200) g value Figure S17. EPR spectra of pristine and used H x(200). It should be noted that the used H x(200) still shows distinct EPR signal corresponding to Vo or Ti 3+ after photocatalytic reaction. Ti 2p 2p 3/2 Used H--x (200) 2p 1/ Binding energy (ev) Figure S18. XPS Ti 2p spectra of pristine and used H x(200). S11

12 CO (a) (b) CH 4 CH CH 2 CH 3 Figure S19. Isotope tracer analyses using H 2O/ CO 2 as the substrates. GC-MS of (a) CO and (b) CH 4 produced over H x(200) under full solar-light irradiation. CO (a) (b) CD 3 CD 4 CD CD 2 Figure S20. Isotope tracer analyses using D 2O/CO 2 as the substrates. GC-MS of (a) CO and (b) CD 4 produced over H x(200) under full solar-light irradiation. S12

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