Construction Of TiO2/red Phosphorus Heterojunction And Its Photocatalytic Performance For Water Splitting

Nowadays,the world energy crisis and environmental pollution become an urgent problem to be solved.The solar energy driven photocatalytic hydrogen production technology based on semiconductor materials have the properties of clean,sustainable and environment-friendly,which can directly convert solar energy into chemical fuel,showing a promising method to solve the energy crisis and environmental pollution.As a typical semiconductor photocatalyst,TiO₂ has gained popular attention and research due to low cost and chemical stability properties.However,the wide band gap(3.2 e V)of TiO₂ inhibits the absorption of visible light,and the high carrier recombination rate greatly limits the practical application.In this paper,two different heterostructures of TiO₂@RP Nanorods and TiO₂@RP hollow spheres were fabricated by compounding non-metallic red phosphorus(RP)with different morphologies of TiO₂.The structural characteristics,hydrogen production performance and reaction mechanism of each system were studied.The main research contents are as follows:(1)Firstly,the precursor of titanate nanotubes was synthesized by hydrothermal method,and TiO₂ nanorods with(116)lattice plane was obtained by high-temperature calcination.And then,the TiO₂@RP nanorod heterostructures were synthesized by vapor deposition method in a sealed quartz tube by mixing amorphous RP and TiO₂ nanorods.By optimizing the mass ratio of TiO₂ and RP in the precursor,the prepared TiO₂@RP(0.4)composites showed remarkable enhancement of photocatalytic hydrogen production compared to TiO₂ nanorods with a maximum hydrogen production rate of 12.9?mol h^-1 under simulated solar irradiation.Theoretical calculation and experimental analysis showed that the direct Z-scheme heterojunction can promote the spatial separation and migration of photogenerated carriers,and improve the lifetime of photogenerated electrons and holes.It is helpful to improve the photocatalytic performance of TiO₂@RP heterostructure for hydrogen production.(2)Mesoporous TiO₂ hollow spheres were synthesized by sol-gel method.RP modified TiO₂ hollow spheres heterostructures(TiO₂@RP)were prepared by chemical vapor deposition using TiO₂ hollow spheres as support materials.By optimizing the loading amount of RP on TiO₂ hollow spheres,TiO₂@RP Hollow spheres show excellent photocatalytic performance for hydrogen production,which can reach 8.62?mol·h-1 under simulated sunlight.The special hollow sphere structure improves the utilization of light.And the heterojunction formed between RP and TiO₂ contributes to the separation and migration of photo generated carriers,improving the photocatalytic performance of hydrogen production.