Preparation Of In₂Se₃-based Photocatalytic Materials And Study On Their Catalytic Performance

Photocatalytic technology is a kind of green technology to solve energy shortage and environmental problems driven by solar energy.However,traditional semiconductor photocatalysts can only absorb ultraviolet light?3-4%of solar energy?due to their wide band gap?such as:TiO₂,ZnO,CdSe,etc.?,which seriously limits the efficiency utilization of light energy.At present,the development of new visible light photocatalytic semiconductor materials is the focus in the photocatalytic field.Diindium triselenide?In₂Se₃?is a kind of III-?compounds,mainly including five predominate crystal structure,the alpha,beta,gamma,delta and kappa,its band gap of 1.36².0 eV and has good visible light absorption and photoelectric response performance,and has the potential for research value and application prospect in the photocatalytic field.This paper selects In₂Se₃ as the main research objectforthefirsttime,buildingthe?-In₂Se₃/TiO₂heterojunction,?-In₂Se₃nanoparticle/?-In₂Se₃ nanosheet?In₂Se₃ NPS?homogeneous and In₂Se₃ NPS/rGO?graphene oxide?homo-heterojunction three system,and the microscopic structure of the samples,the photoelectric performance,photocatalytic properties and the mechanism are studied,specific work contents are as follows:?1?The?-In₂Se₃/TiO₂ catalysts with different TiO₂ contents is prepared via a hot-injection method.The prepared catalysts are used to photocatalytic hydrogen evolution.The experimental results show that the photocatalytic hydrogen production rate of?-In₂Se₃/TiO₂is higher than that of the monomer?-In₂Se₃,and the optimal hydrogen production rate of?-In₂Se₃/TiO₂?2145.17?mol/?g·h??is 2.82 times higher than that of the monomer?-In₂Se₃?760.34?mol/?g·h??.The enhanced photocatalytic performance is attributed to the formed heterogeneous structure between?-In₂Se₃ and TiO₂,which improves the separation efficiency of electron and holes in favour of the photocatalytic performance.?2?The?-In₂Se₃ nanoparticles/?-In₂Se₃ nanosheets?short for In₂Se₃ NPS homogeneous?are prepared by simple solvent thermal method using triethylene glycol?TEG?as solvent.The growth mechanism and photocatalytic reaction mechanism of homogeneous are investigated and the samples are applied to photocatalytic hydrogen production and reduction of toxic heavy metal ions.The results show that the reaction time is the key to prepare homogeneous,and the photocatalytic activity of?-In₂Se₃/?-In₂Se₃ homogeneous prepared with different reaction time is significantly different.Compared with the pure?-In₂Se₃ nanoparticles,the staggered structure of homogenous enables the effective separation of charge carriers and reduces the carrier recombination rate,thus showing better photocatalytic activity in the photocatalytic hydrogen generation and removal of toxic Cr?VI?experiments.The photocatalytic hydrogen production rate of In₂Se₃ NPS-2 obtained with reaction time of 24 h is 1347.6?mol/?g·h?,and the removal rate of Cr?VI?is 94.9%,which is 4.34 and 4.12 times of that of ?-In₂Se₃ nanoparticles,respectively.After four cycles,?-In₂Se₃/?-In₂Se₃ homogeneous still show good stability in the photocatalytic reaction process.?3?Firstly,GO is prepared by Hummer method.Then,in the growth process of?-In₂Se₃/?-In₂Se₃ homogenous,the GO after ultrasonic stripping is added to prepare?-In₂Se₃/?-In₂Se₃-rGO homo-heterogeneous,and the optimal content of GO is explored.The results show that In₂Se₃ NPS/rGO-7.5%show the optimal photocatalytic hydrogen production rate up to 4497.24?mol/?g·h?,and show good hydrogen production stability.Compared with ?-In₂Se₃/?-In₂Se₃,the enhanced photocatalytic activity of ?-In₂Se₃/?-In₂Se₃-rGO is attributed to the higher light energy utilization,a larger specific surface area owing to the introduction of rGO,further improved separation efficiency of photogenic carriers due to the formation of homo-heterogeneous structure.