Supporting Information
Dye-sensitized MIL-101 MOF loaded with Ni/NiOx nanoparticles for efficient visible-light-driven hydrogen generation
Xin-Ling Liu,1 Rong Wang,1 Ming-Yi Zhang,2 Yu-Peng Yuan,1, a and Can Xue3, a
1 School of Chemistry and Chemical Engineering, and Innovation Lab for Clean Energy & Green Catalysis, Anhui University, Hefei 230036, P. R. China
2 Key Laboratory for Photonic and Electronic Bandgap Materials, Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin 150025, P. R. China.
3 Solar Fuels Lab, School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)
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*Author to whom correspondence should be addressed. Email: R.C. (Y. P. Yuan) and (C. Xue)
1. Synthesis of MIL-101 MOF
The catalyst MIL-101 was prepared using the protocols described by Férey et al. with a little change.[1] A mixture of Cr(NO3)3·9H2O (2.7 g), terephthalic acid (H2bdc) (1.1 g), and 100 uL HF in 30 mL H2O was heated to 220 oC for 8 h in a Teflon-lined stainless steel bomb. The resultant green solids were first soaked repeatedly in water at 70 oC for 3 h and then soaked in ethanol at 70 oC for 6 h with replacing the ethanol every 3 hours. Finally the product was centrifugal separation and dried overnight in an oven at 60 oC .
2. Characterizations
X-ray powder diffraction (XRD) data were collected on a Shimadzu XRD-6000 X-ray diffractometer using Cu Kα1 radiation. The acceleration voltage and the applied current were 40 kV and 40 mA, respectively. The morphologies of the prepared samples were observed by field emission scanning electron microscope (SEM, S-4800, Hitachi) and transmission electron microscope (TEM, JEM-2100F, JEOL). UV-vis absorption spectra were collected on a UV/Vis/NIR spectrophotometer (Japan) over the spectral range 200-800 nm (U-3900, HITACHI). Photoluminescence spectra (PL) were recorded on a HITACHI F-4600 fluorometer (Japan). X-ray photoelectron spectra (XPS) were measured on ESCALAB250 spectrometer (Thermo-VGScientific) using Mg radiation (1253.6 eV). C (1s) peak (284.6 eV) was used to calibrate the binding energy values.
3. Photocatalytic H2 generation
Photocatalytic H2 generation was carried out in a 100-mL closed Pyrex reactor with a quartz widow. Typically, 20 mg of MIL-101 photocatalysts and various amount of Erythrosin B dye were suspended in 20 mL aqueous solution of triethanolamine (TEOA) aqueous solution (5 vol% TEOA). Ni-catalyst for hydrogen generation was in-situ photo-deposited upon MIL-101 surface through injecting Ni(NiO3)2 solution into the reactor. The residual air in reactor was first degassed with argon. Then the photocatalytic hydrogen generation was triggered by irradiating the suspension with a 300-W xenon lamp coupled with a UV cut-off filter (l > 420 nm). The gas products were analyzed periodically through a gas chromatograph (GC-1690, Kexiao, China) with a TCD detector.
Reference:
[1] G. Férey, C. Mellot-Draznieks, C. Serre, F. Millange, J. Dutour, S. Surble, and I. Margiolaki, “A chromium terephthalate-based solid with unusually large pore volumes and surface area,” Science 309, 2040 (2005).
FIG. 1 XRD patterns of (A) pristine MIL-101 and (B) Ni-loaded MIL-101.
FIG. S2 UV-vis absorption spectrum of pristine MIL-101.
FIG. S3 UV-vis absorption spectra of ErB (black line), and suspension of MIL-101 and ErB dye (red line).
FIG. S4 TEM image of 5 wt% Ni/NiOx nanoparticles loaded MIL-101.
FIG. S5 XRD patterns of (A) MIL-101 and 5 wt% Ni-loaded MIL-101 (B) before and (C) after H2 generation.
FIG. S6 XPS spectra of Ni 2p at various reaction time for H2 generation.
FIG. S7 Schematic illustration of the charge transfer route in the system of ErB/MIL-101/Ni@NiOx.
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