Preparation And Photoelectrocatalytic Activities Of TiO₂/2D?ReS₂,GeTe?thin Film Heterojuction Photocatalysts

Converting solar energy into chemical fuel is one of the most promising ways to realize a sustainable energy economy.Photocatalytic splitting of water to produce hydrogen is one of the promising research directions.The pristine titanium dioxide film is subject to serious photogenerated carrier recombination which results in low efficiency of photocatalytic decomposition of water to produce hydrogen.Likewise,single two-dimensional?2D?material is difficult to be practically used in photocatalytic applications alone due to insufficient light absorption.Therefore,more effortis required to improve the photocatalytic efficiency of the titanium dioxide-based catalyst.The construction of TiO₂/2D semiconductor thin-film heterojunction photocatalyst can effectively synergize the advantages of the two materials.Different from the nanocomposite powder material,the thin-film photocatalyst in this study is obviously layered heterostructure,green and environmentally friendly and can be recyclable,with high catalytic efficiency.The main results are as follows:?1?2D layered ReS₂ nanosheets were prepared by ball milling and ultrasonic liquid-assisted exfoliation.The nanosheets are about 200 nm in size and less than 10nm in thickness.TiO₂/ReS₂ thin film heterojunction was fabricated by drop coating ReS₂ nanosheets on 1D TiO₂ vertical nanorods?NRs?array thin film.The TiO₂/ReS₂semiconductor photoanode has a maximum photocurrent density of 1.3 mA/cm² with a solution concentration of ReS₂ of 0.2 mg/mL and a loading amount of ReS₂ nanosheets of 0.2 mg.The TiO₂/ReS₂photoanode possess a maximum efficiency of hydrogen production by photoelectric conversion of 0.48%,which is 2.56 times that of the pure phase TiO₂ NRs array.?2?TiO₂/GeTe heterojuction photoanode has excellent photoelectrocatalytic properties.Using a?AM 1.5G/300W?Xe lamp light source,at 0.3 V bias,after air plasma modification,the photoelectric conversion hydrogen production efficiency of TiO₂/GeTe photoanode is about 1.44%,which is 3 times that of the pure phase TiO₂NRs array thin film and 2.25 times that of the heterojuction without modification.Meanwhile,under a 380 nm monochromatic light irradiation,the modified sample has a maximum photocurrent density of 4.0 mA/cm².Under a 380 nm monochromatic light source,its IPCE is as high as 55%,which is 11 times that of pure-phase TiO₂ nanorods?NRs?array thin film and 1.6 times that of unmodified composite samples.The formation of TiO2/GeTe composite photoanode can effectively enhance light absorption,and at the same time,effectively improve the separation efficiency and transfer efficiency of the photo-generated carriers,and then gain efficient photoelectrocatalytic activity.