Post-Solvothermal Route for High-Performance Photocatalytic H 2

Transcription

1 Supporting information for: MIL-125-NH 2 Core-Shell Particles Produced by A Post-Solvothermal Route for High-Performance Photocatalytic H 2 Production Bingxing Zhang, Jianling Zhang,* Xiuniang Tan, Dan Shao, Jinbiao Shi, Lirong Zheng, Jing Zhang, Guanying Yang and Buxing Han Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Colloid and Interface and Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences Institute of High Energy Physics, Chinese Academy of Sciences zhangjl@iccas.ac.cn S-1

2 Figure S1. SEM and TEM images of the pristine MIL-125-NH 2. Scare bar, 500 nm in (a) and 1 µm in (b). MIL-125-NH2@TiO2 MIL-125-NH Field (mt) Figure S2. ESR spectra of MIL-125-NH 2 and MIL-125-NH 2. MIL-125-NH 2 gives a major feature with a g-value of 2.040, which can be assigned to an electron trapped around oxygen vacancy. Such signal is much weaker for MIL-125-NH 2. S-2

3 4h 3h Transmittance 2h 1h MIL-125-NH Wavenumber (cm -1 ) Figure S3. FTIR spectra of MIL-125-NH 2 and its derivatives formed in ethanol solution at different time. The bands at 1433 and 1536 cm -1 of the samples are referred to symmetrical stretching vibration of carboxylates groups. The band at 1390 cm -1 is assigned to bending terephthalate group to titanium metal. All these groups are gradually decreased with the prolonged evolution time, indicating the loss of organic linkers from MOF. Accordingly, the bands located at cm -1 can be attributed to Ti-O stretching and Ti-O-Ti bridging stretching modes, which gradually predominate with the prolonged evolution time. The band at 1661 cm -1 correspond to carboxyl group from uncoordinated aromatic carboxylic acid, which is obvious in the MOF derivatives obtained at 1 h and 2 h while nonexistent in original MOF. That indicates the presence of dissociated ligands in the MOF derivatives obtained at 1 h and 2 h. S-3

4 100 Mass (%) Reaction time (h) Figure S4. Mass loss of the MIL-125-NH 2 derivatives synthesized in ethanol solution at different solvothermal time. V ads (STP) (cm 3 g -1 ) h 3 h 4 h P/P 0 Figure S5. N 2 adsorption-desorption isotherms of MIL-125-NH 2 derivatives obtained at solvothermal time of 1 h, 3 h and 4 h. The BET surface areas of the three samples are 893, 552 and 352 m 2 g -1, respectively. The hysteresis loop of the N 2 sorption isotherm is more obvious for the sample obtained at longer solvothermal time. S-4

5 Figure S6. SEM image of MIL-125-NH 2 after solvothermalized at 150 o C in ethanol solution for 1 h (a), 2 h (b), 5 h (c) and 10 h (d). Scare bar, 300 nm. Figure S7. TEM images of the MIL-125-NH 2 after solvothermalized at 150 o C (a), 160 o C (b) and 170 o C (c) in ethanol solution for 10 h. Scare bar, 500 nm. Figure S8. TEM image of MIL-125-NH 2 after solvothermalized at 200 o C in ethanol without TAA for 2 h. Scare bar, 2 µm in (a) and 500 nm in (b). S-5

6 Figure S9. SEM image (a), TEM images (b, c) and XRD pattern of MIL-125-NH 2 synthesized in propanol solution for 2 h. Scare bars, 1 µm in (a), 500 nm in (b), and 200 nm in (c). Figure S10. SEM image (a), TEM images (b, c) and XRD pattern of MIL-125-NH 2 synthesized in methanolic solution for 2 h. Scare bars, 1 µm in (a), (b), and 200 nm in (c). S-6

7 24 -Z'' (Ω) Z' (Ω) Figure S11. Electrochemical impedance spectra (EIS) Nyquist plots for the pristine MIL-125-NH 2 (black) and MIL-125-NH 2 synthesized at 2 h (red). The EIS confirms a higher conductivity of MIL-125-NH 2, which provides a faster electron transfer than MIL-125-NH 2. It is beneficial for realizing an efficient separation of the photoinduced electron-hole pairs in the photocatalytic process. Intensity MIL-25-NH2 1h 2h 3h 4h Wavelength (nm) Figure S12. UV/Vis diffuse reflectance spectra of MIL-125-NH 2 and its derivatives formed at different time. S-7

8 Intensity Wavelength (nm) Figure S13. PL emission spectra for the pristine MIL-125-NH 2 (black) and MIL-125-NH 2 synthesized at 2 h (red) (excited at 380 nm). The PL emission spectrum of MIL-125-NH 2 is much weaker than that of the pure MIL-125-NH 2, indicating that the radiative electron-hole recombination in MIL-125-NH 2 is more effectively suppressed by extracting the electrons from MIL-125-NH 2 to TiO 2 nanosheets. S-8

9 Figure S14. SEM images (a, b), TEM image (c) and XRD pattern (d) of MIL-125-NH 2 after photocatalytic H 2 production for three times. Scare bar, 1 µm in (a) and 500 nm in (b) and (c). S-9

10 Figure S15. SEM images (a, b) and XRD pattern (c) of MIL-125-NH 2 after photocatalytic H 2 production for three times. (d) Recycling tests for MIL-125-NH 2. Scare bar, 2 µm in (a) and 500 nm in (b). S-10