Preparation And Photocatalytic Performance Of Indium-based Sulfide Nanomaterials

Indium-based sulfide nanomaterials have attracted extensive attention in photocatalytic applications due to their suitable bandgap,high absorptivity and strong carrier transport capacity.However,there are still some problems,such as low photocatalytic efficiency,difficult preparation of thin film electrodes and wasting of disposable powders.All these limits their further application as photocatalyst.According to the background,we explore two methods to optimize their photocatalytic performance,including modulating the microstructure and constructing nano-heterojunctions.In this paper,we have investigated the controllable growth of single crystal indium nanowires,the preparation of ZnIn₂S₄NCMAs and its photocatalytic performance,the construction of ZnO/In₂S₃heterojunction and its PEC performance and the preparation of CuInS₂NSAs and its PEC performance.The main tasks are as follows:?1?The controllable growth of single crystal indium nanowires.Indium nanowires were synthesized on zinc substrate through a one-step solvothermal method using InCl₃·4H₂O and CH₃CSNH₂ as indium source and sulfur source,respectively.Experimental results show that we can obtain the highest quality indium nanowires at 200°C for 2 h,when the ratio of indium source and sulfur source is 2:5.And the indium nanowires have a core-shell structure surrounded by a chalcogen compound?ZnxInySz?,which can be removed by pickling.The cleaned indium nanowires would be used in a wider range of applications.?2?The preparation of ZnIn₂S₄ NCMAs and its photocatalytic performance.On the basis of synthesizing indium nanowires with core-shell structure,the uniform ZnIn₂S₄ NCMAs on zinc substrate were obtained by further prolonging the reaction time without template and auxiliary agent.The formation process was explained by a novel corrosion-exchange-self-assembly growth mechanism.Photocatalytic degradation experiments show that it has excellent photocatalytic activity on organic dyes,tetracycline and 2,4,6-tribromophenol,which can be attributed to the fact that three-dimensional hierarchical array structure can effectively promote the absorption of light and the separation of photogenerated carrier.The active species involved in the degradation are h⁺and·O^2-.?3?The construction of ZnO/In₂S₃ heterojunction and its PEC performance.The heterojunction were constructed by modifying ZnO nanoparticles on In₂S₃ NSAs,and its bandgap is increased from 2.36 eV of In₂S₃ to 2.42 eV.The photocurrent density of the ZnO/In₂S₃-4h at bias voltage of 1.23 V_RHE is 450?A/cm²,which is 12.8 times larger than that of the pristine In₂S₃?35?A/cm²?.This can be attributed to the reduction of surface impedance,which promotes the separation of photogenerated carriers.Besides,the photoelectric conversion efficiency of ZnO/In₂S₃-4h at 0.6 V_REH is 10 times larger than pristine In₂S₃.?4?The preparation of CuInS₂ NSAs and its PEC performance.A facile self-templated method is developed to synthesize CuInS₂ NSAs in situ on fluorine-doped tin oxide?FTO?glasses coated with In₂S₃ NSAs.The vertically oriented CuInS₂ nanosheets show an ultrathin thickness of5.8 nm?¹8?112?planes?,which significantly promote the separation of photogenerated carriers.The UV-visible diffuse reflection measurements indicate a strong and wide absorption range?250-800 nm?of the as-synthesized CuInS₂ NSAs with a 1.46 eV bandgap.Due to these properties,the CuInS₂ NSAs exhibit a photocurrent of⁰.09 mA/cm² at-0.05V vs.RHE.