•Ni(dmgH)2 complex can serve as active sites to promote H2 generation of MOFs.•The efficient charge transfer from MOF to Ni(dmgH)2 causes the enhanced H2 production.•The low cost and easy operation makes Ni(dmgH)2 having great potential for photocatalytic H2 production.Metal-organic frameworks (MOFs) have been tremendously used as photocatalysts for H2 generation in recent years. Lacking native active sites (so-called co-catalyst) for H2 generation motivates the incorporation of noble metals and their molecular complexes, hydrogenase active site mimics into MOFs to promote H2 generation. We herein report an noble-metal-free photocatalytic H2 generation system consisting of Erythrosin B dye-sensitized MIL-101(Cr) as a light absorber and Ni(dmgH)2 as a co-catalyst. It is found that Ni(dmgH)2 can serve as an efficient co-catalyst to boost H2 generation in the presence of triethanolamine (TEOA) as an electron donor under visible light irradiation. The optimal MIL-101(Cr)/Ni(dmgH)2 hybrid (5 wt% Ni(dmgH)2) displays a hydrogen H2 rate of 45.5 μmol h−1, which is 10 times greater than the control sample without Ni(dmgH)2 loading. This paper provides a novel design route for active H2 generation systems by combining molecular complexes of earth-abundant metal and MOFs photocatalysts.Download high-res image (234KB)Download full-size image

Herein we used a rapid “microwave (MW)-assisted heating synthesis” to produce a crystalline polyimide in minutes. Importantly, the present strategy avoids the tedious washing process for the produced polyimide. Benefiting from the relatively high crystallinity, the obtained polyimide shows improved photocatalytic H2 production under visible light irradiation.

Metal–organic frameworks (MOFs) MIL-88A hexagonal microrods as a new photocatalyst show an active performance for methylene blue (MB) dye decolorization using visible light. MB decolorization over the MIL-88A photocatalyst follows first-order kinetics. The addition of a H2O2 electron acceptor can markedly enhance the photocatalytic MB decoloration performance of MIL-88A. Moreover, MIL-88A showed a very stable activity for MB decoloration after four consecutive usages. Owing to the advantages of the visible light response, low cost and abundance in nature, this active MIL-88A MOF photocatalyst would have great potential for environmental purification.

Inorganic–organic hybrid NiO–g-C3N4 photocatalysts with different NiO contents were prepared through a simple calcination method. The as-prepared photocatalysts were characterized by powder X-ray diffraction (PXRD), thermo-gravimetric analysis (TGA), the Brunauer–Emmett–Teller (BET) method, high-resolution transmission electron microscopy (HR-TEM), and UV-vis diffuse reflection spectroscopy (UV-vis). The photocatalytic degradation of methylene blue (MB) over NiO–g-C3N4 was investigated. The incorporation of NiO caused a red-shift of the UV-vis absorption edge of g-C3N4. And the NiO–g-C3N4 photocatalysts exhibited a significantly enhanced photocatalytic activity in degrading MB using visible light, and the optimum hybrid photocatalyst with 6.3 wt% NiO showed a 2.3 times enhanced MB degradation rate. The improved photoactivity of NiO–g-C3N4 photocatalysts could be ascribed to the effective interfacial charge transfer between NiO and g-C3N4, thus suppressing the recombination of the photoexcited electron–hole pairs. Furthermore, the NiO–g-C3N4 photocatalyst showed excellent stability for the photocatalytic degradation of MB.

•G-C3N4 nanosheets were synthesized via the urea polymerization in Ar atmosphere.•The g-C3N4 nanosheets are very active for visible-light-driven H2 production.•The highest H2 rate was up to 1.4 mmol h−1 g−1 (2.6% quantum efficiency at 420 nm).The effect of heating time on the polymerization processes of urea into g-C3N4 nanosheets was studied in Ar atmosphere. It was found that heating time had a great influence on the crystalline quality, specific surface area (SBET) and photocatalytic H2 production of the obtained g-C3N4 nanosheets. G-C3N4 nanosheets with some degree of disorders in crystal structure were formed within 1 h at 550 °C, and these structural disorders maintained after 4 h, however disorders disappeared after extended heating of 6 h. G-C3N4 nanosheets with similar disorders in the crystal structure hold similar SBET and exhibit comparable H2 production rates. The highest H2 production rate of 1.4 mmol h−1 g−1 occurs after 8 h heating, corresponding to 2.6% quantum efficiency at 420 nm.

Herein we used a rapid “microwave (MW)-assisted heating synthesis” to produce a crystalline polyimide in minutes. Importantly, the present strategy avoids the tedious washing process for the produced polyimide. Benefiting from the relatively high crystallinity, the obtained polyimide shows improved photocatalytic H2 production under visible light irradiation.

Metal–organic frameworks (MOFs) MIL-88A hexagonal microrods as a new photocatalyst show an active performance for methylene blue (MB) dye decolorization using visible light. MB decolorization over the MIL-88A photocatalyst follows first-order kinetics. The addition of a H2O2 electron acceptor can markedly enhance the photocatalytic MB decoloration performance of MIL-88A. Moreover, MIL-88A showed a very stable activity for MB decoloration after four consecutive usages. Owing to the advantages of the visible light response, low cost and abundance in nature, this active MIL-88A MOF photocatalyst would have great potential for environmental purification.