Preparation And Performance Of Visible-light-response Si,BiVO₄ And ZnIn₂S₄ Photoanodes

Rapidly human development has produced more and more energy and environmental problems.Photocatalyst splitting water has attracted a wide attention due to its advantages such as utilization of solar energy,production of clean energy--hydrogen.However,the development of photocatalyst has been hindered by its non-recyclable application.Thus,photocatalyst,fixed on the electrode,was assemble to form a photoelectrochemical cell?PEC cell?to solve the above problem.Moreover,PEC cells can also enhance hydrogen production efficiency by applying a bias potential.In addition to hydrogen production,photoelectrochemistry is also a means of evaluating the photoelectrocatalytic properties of semiconductors.Owing to simple,stable,and non-toxic wide band-gap semiconductors?TiO₂,ZnO and WO₃?,they were widely used as photoelectrode to produce hydrogen.However,the solar-to-hydrogen efficiency of wide band-gap semiconductors have been hampered by their limited quantum efficiency and utilization of sunlight.Therefore,the visible-light-response Si,BiVO₄ and ZnIn₂S₄ films were fabricated as photoanodes and studied their PEC properties in this paper as following:Si nanowire arrays?SiNWs?and porous nanostructure Si?PSi?photoelectrodes were prepared by chemical etching method.In this study,it was found that the SiNWs electrode exhibited higher photocurrent density(1.10 mAcm^-3),photo-to-current conversion efficiency?0.65%?,and excellent photo-corrosion resistance.Obviously,the PEC performances of SiNWs were superior than PSi and Si wafers.The enhanced PEC properties of SiNWs electrode may be attributed to its superior light absorption ability,high specific surface area,higher carrier concentration,lower interface resistance,and higher pathway for carrier transfer to reduce charge recombination and improve the charge lifetime.We have prepared different amount of Mo doped into BiVO₄ transparent porous films via a modified metal organic decomposition method?MOD?,and studied the PEC properties of the above samples.It obviously showed that the 10at%Mo:BiVO₄porous film exhibited better photoelectrocatalytic performance due to higher carrier concentration,lower interface resistance,enhancing charge separation/transfer rate,suppressing recombination,and higher surface electron injection efficiency.The single-crystal hexagonal phase of ZnIn₂S₄ nanosheet arrays?NSAs?films were fabricated by a one-step hydrothermal method.Through different temperatures?150-250°C?,time?1-6 h?and substrates,it was found that the uniform ZnIn₂S₄ NSAs films were fabricated at 200°C and on FTO substrates.The growth mechanism of ZnIn₂S₄ NSAs films was also revealed by a series of hydrothermal time.The 1h,2h,4h and 6h ZnIn₂S₄ NSAs films exhibited difference in optical properties and PEC performance.The results showed that the 2h sample performed superior PEC properties due to its high specific surface area,suitable nanosheet diameter,the most effective charge transport pathway to reduce electrons and holes recombination.