Preparation Of CuInS₂?AgInS₂?/TiO₂ Heterojunction Photocatalysts And Study On Their Photocatalytic Activity

Photocatalytic technology is considered as one of the effective means to solve energy shortage and environmental pollution due to its many advantages such as green,pro-environmental,high-efficiency,no secondary pollution and directly converting solar energy into chemical energy.Photocatalyst has been widely studied as the core of this technology.Among them,the representative TiO₂is considered as one of the most promising photocatalysts.However,the photocatalytic efficiency of the photocatalyst is severely limited due to a large band gap and easy recombination of photogenerated carriers.Therefore,this paper uses?-?-?group sulfide bimetals as photosensitizers of TiO₂to construct CuInS₂/TiO₂and AgInS₂/TiO₂heterojunction photocatalysts.And the mechanism of its enhanced photocatalytic activity has been studied,and the specific results are as follows:?1?CuInS₂/TiO₂heterojunction photocatalysts with different CuInS₂loadings were prepared by in-situ growth method and used for photocatalytic hydrogen production and photodegradation of rhodamine B?Rh B?.Photocatalytic experimental results showed that the catalytic activity of the CuInS₂/TiO₂heterojunction photocatalyst is significantly improved compared to TiO₂.The degradation for Rh B and hydrogen production rates of 1%CuInS₂/TiO₂photocatalyst were 8.28 and 1.68 times that of pure TiO₂,respectively.The enhancement of photocatalytic activity is due to the sensitization of CuInS₂which can effectively broaden the spectral response range and form a heterojunction with TiO₂to improve the separation efficiency of photogenerated carriers.?2?First,The hydrothermal experiments showed that the best preparation conditions of AgInS₂single-phase nanocrystals are L-cys as the ligand,the p H of the reaction solution is about 10 and the sample is hydrothermally heated at 180?for 24 h.Then the AgInS₂/TiO₂Z-type heterojunction photocatalyst was obtained by in-situ hydrothermal method.It was found that the sensitization of AgInS₂can effectively enhance the light capture ability of the sample,and the formation of heterojunctions effectively improved the separation efficiency of photo-generated carriers and accelerated the transfer of interface charges.The sample showed the best catalytic activity when AgInS₂was loaded at 5%,and the photodegradation Rh B rate was 2.42 times that of pure TiO₂.