| At present,energy shortages and environmental pollution were the focal problems in worldwide.The development and use of renewable energy,especially solar energy,was one of the effective ways to solve these problems.Solar energy was one of the most abundant and inexhaustible natural resources.And it had been considered as a promising alternative to fossil fuels to secure a permanent energy supply for the future with the growing energy and global environmental problems.However,the discontinuity and instability of solar energy made it impossible to directly use as an industrial and domestic energy supply.Hydrogen was also a regenerative and environmentally friendly fuel of the future since its combustion generates only water.Thus,it was highly expected that H2 could be generated through the most promising and economic pathways,especially,using a source of renewable energy.Photocatalytic water splitting into H2 and O2 using solar energy and semiconductors was a promising way to solve both the solar energy storage and green production of H2 fuel.And scientists were looking for superior semiconductor materials to improve light absorption capability and photocatalytic conversion efficiency.However,due to the rapid electron-hole recombination rate of photocatalysts,photocatalytic hydrogen evolution technology still had a low energy conversion efficiency.Metal-organic frameworks（MOFs）were a new class of crystalline porous organic-inorganic hybrid materials,and it has received extensive attention in energy storage and conversion.As a zirconium-based MOF with semiconductor behavior,UiO-66 was a potential material for photocatalytic hydrogen production.In this paper,two kinds of MOF/semiconductor composites with visible light response were constructed to obtain photocatalysts with excellent performance.The main research contents were as follows:（1）Photocatalytic hydrogen production performance of UiO-66-（SH）2 and g-C3N4composites.In this paper,a series of UiO-66-（SH）2/g-C3N4 composites with different ratios were prepared,and the effects of photocatalytic hydrogen production were investigated.Through the photocatalytic hydrogen production test of the composite material,it was found that when the addition amount of g-C3N4 nanosheet was 50 wt%,the optimum hydrogen production rate was 1193.6μmol h-1 g-1,which was 2.3 times that of g-C3N4 nanosheet and 5.2 times that of bulk g-C3N4.The results showed that the composite had excellent hydrogen production activity and good stability.The photocatalytic mechanism of the composite was further investigated,and the enhanced photocatalytic hydrogenation rate was related to the increased specific surface area,faster electron transfer capacity and lower electron-hole recombination efficiency.（2）Photocatalytic hydrogen production performance of ZnIn2S4 and UiO-66composites.Here,the composite for photocatalytic hydrogen production via introduction of UiO-66 nanospheres into flower-shaped ZnIn2S4 microspheres（ZIS/U6）was described.The optimum composite with 20 mg UiO-66 displayed the higher photocatalytic rate of 1860.9μmol g-1 h-1 under visible-light irradiation,which was nearly 3 times higher than that of ZnIn2S4.The improved photocatalytic H2 rate was mainly benefited from effective electron transfer between ZnIn2S4 and UiO-66.And we also introduced UiO-66 modified with functional groups（UiO-66-NH2,UiO-66-（SH）2）into ZnIn2S4 to prepare the corresponding composite materials.UV-visible diffuse reflectance spectroscopy results showed that UiO-66-NH2/ZnIn2S4,UiO-66-（SH）2/ZnIn2S4 composites had enhanced visible light absorption,but their photocatalytic H2 rate was lower than ZIS/U6 photocatalyst.The photocatalytic mechanism showed that the two composite materials had different electron transport paths relative to ZIS/U6. |
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