Design And Performance Of Spinel Indium Sulfide Based Composite Photocatalysts

The widespread use of dyes and heavy metals is causing increasing environmental pollution.The use of semiconductor photocatalysts for the redox purification of pollutants is one of the effective ways to mitigate environmental pollution.Heterostructured photocatalysts composed of different semiconductors can reduce the electron-hole complexation rate and improve light utilization.In this study,two different synthetic methods were used to investigate the photocatalytic performance of indium spinel sulfide composite photocatalysts.The specific process was divided into the following steps:（1）Firstly,composites consisting of Sn O₂ nanocrystals with defective energy levels and spinel-type In_3-xS₄ flower-like microspheres were prepared by a one-pot method.A novel Sn O₂/In_3-xS₄ composite with a Z-shaped heterostructure with oxygen vacancy defects was constructed.Similarly,Ti O₂/In_3-xS₄ composites with oxygen vacancies were successfully prepared by a simple one-pot method,and their morphological structures were explored by XRD,XPS,SEM and TEM characterisation,performance tests were carried out by electrochemical and photocatalytic reactions.The best performing SO-IS-2 sample among the Sn O₂/In3-x S₄ composites showed 12.8times and 6.3 times the reaction rate of visible light-catalyzed degradation of Rh B and reduction of Cr（VI）than In_3-xS₄,and showed 32.0 times and 76.0 times that of Sn O₂,respectively.The best performing TO-IS-0.6 sample among the Ti O₂/In₃-_xS₄composites showed reaction rate constants 10.9 and 38.0 times higher than those of pure In_3-xS₄ and Ti O₂,respectively,in the photocatalytic degradation of Rh B;and 5.8and 43.5 times higher than those of pure In_3-xS₄ and Ti O₂,respectively,in the photocatalytic reduction of Cr（VI）.（2）Secondly,SnIn₄S₈/In_3-xS₄ and Zn In₂S₄/In_3-xS₄ composites were successfully prepared by two-step method,and their morphological structures were investigated by XRD,XPS,SEM and TEM characterization.The electrochemical properties of the synthesized samples were tested to investigate their photocatalytic performance,SIS-IS-1 composite had the best degradation effect among the SnIn₄S₈/In₃-x S4 composites,the photocatalytic degradation reaction rate of Rh B was 8.1 times that of In_3-xS₄ and3.7 times that of SnIn₄S₈,respectively.The photocatalytic reduction of Cr（VI）was 6.4times that of In_3-xS₄ and 3.7 times that of SnIn₄S₈,respectively,while ZIS-IS-0.6 in the Zn In₂S₄/In_3-xS₄ composite had the best degradation effect,with the photocatalytic degradation of Rh B and the reduction of Cr（VI）at reaction rates were 8.9 and 5.9 times higher than those of In_3-xS₄,3.6 and 4.6 times higher than those of Zn In₂S₄,respectively.