Hydrothermal Synthesis And Photocatalytic Performance Of MoS₂/ZnS

In recent years,the use of semiconductor materials to photodegrade pollutants has become the focus of research.Unlike the single semiconductor photocatalytic materials,the composites semiconductor can effectively reduce the recombination of photogenerated electron hole pairs and improve the catalytic activity of the catalyst.In this paper,MoS2/ZnS composite materials were successfully prepared by two-step hydrothermal method.And the photocatalytic performance and photocatalytic reaction mechanism were studied.First,ZnS microspheres were prepared by hydrothermal method.Then we dispersed ZnS into Molybdenum disulfide(MoS2).MoS2/ZnS composite materials were prepared by two-step hydrothermal method by changing the reaction time,reaction temperature,ratio of Mo:Zn and Mo:S.The crystal structure and microstructure were characterized and analyzed by XRD,SEM and EDS.The polar analysis of the photocatalytic degradation efficiency of rhodamine B solution using MoS2/ZnS composites was used as an indicator to obtain the primary and secondary relationship between the experimental parameters and the preparation effect.Then we obtain the optimized preparation process: Mo:Zn ratio is 1:0.5;reaction time is 20h;reaction temperature is 170°C;Mo:S ratio is 1:5.Based on the optimization parameters,three different types of surfactants were added and the experiments of different concentration gradient were designed to explore the effect on the morphology and structure of MoS2/ZnS composite.It was found that the morphology of MoS2/ZnS composites material was decentralized and not agglomerated by using nonionic surface-active PVP.The morphology of MoS2/ZnS composites materials with CTAB and SDBS was not easy to control,which may be related to the molecular structure of surfactants.Second,the photodegradation efficiency of MoS2/ZnS composites materials prepared by adding different types of surfactants for Rhodamine B solution was tested.The results showed that MoS2/ZnS composites materials prepared by adding PVP had the highest degradation efficiency of 93%,followed by MoS2/ZnS composites materials prepared by using SDBS whose degradation efficiency was 88%.Finally,MoS2/ZnS composites materials prepared by adding CTAB had a degradation efficiency of 85%.Finally,the photocatalytic degradation efficiency of MoS2/ZnS composites materials for different dyes were studied.The results showed that the degradation efficiency of MoS2/ZnS composites materials on methylene blue and Rhodamine B were 98% and 90%,respectively.But the degradation efficiency of MoS2/ZnS composites materials on methyl orange was only 70%.The effect of different light sources on the photocatalytic activity of MoS2/ZnS composites materials was also studied.The degradation efficiency of MoS2/ZnS composites materials was 90% and 65% under incandescent lamp and UV lamp,respectively.It shows a better catalytic activity under incandescent lamps.