Preparation Of Transition Metal Sulfide/Carbon Nitride Composites And Research On Their Photocatalytic Activity

The energy crisis and environmental pollution are issues that human beings urgently need to solve.Photocatalytic technology is widely used in energy and environmental fields.The use of ambient photocatalytic methods can solve low concentrations of refractory organic pollutants.However,at present,there are some technical difficulties in environmental photocatalysis appliaction.Therefore,the purpose of this system is to construct high-efficiency photocatalysts and explore their structure-activity relationship,and solve these research frontiers and hot issues based on theory and fact.There are 3 ways to solve the above key problems:improving oxidation potential and mineralization capacity by reducing energy band position;using nanostructures to shorten the diffusion distance and improve the living;using a composite structure to promote charge separation and migration and improve performance.The main contents of this research:The TaS₂ material was synthesized by high temperature solid state reaction,2D-C₃N₄was prepared by thermal polymerization and thermal stripping,and TaS₂/2D-C₃N₄ material was prepared by simple grinding method.The photocatalytic performance of the sample was analyzed by a series of characterizations,which indicated that metal TaS₂ can effectively capture and extract 2D-C₃N₄ photogenerated electrons,thereby improving the separation and transfer efficiency of e^--h⁺pairs.In the photocatalytic degradation of pollutants,the optimal ratio of TaS₂/2D-C₃N₄ prepared in 100 minutes to decontaminant RhB was 92%,which is about 25%higher than that of monomer 2D-C₃N₄.The Nb_0.75Ta_0.25S₂/2D-C₃N₄ complex was synthesized and proved to be prepared successfully by XRD and FT-IR characterization.The other series of characterizations prove that the metal Nb_0.75Ta_0.25S₂ can be used as an electron trap for effective capturing 2D-Photogenerated electrons of C₃N₄,which ultimately improve the separation and transfer efficiency of e^--h⁺pairs and photocatalytic efficiency.When the percentage of loading of Nb_0.75Ta_0.25S₂ is 5%,the catalyst shows its best photocatalytic performance,and the degradation efficiency of RhB can be up to 86.6%.By regulating the proportion of precursors,a ternary metal sulfide Nb_0.9Ta_0.1S₂ differing from the previous chapter was prepared.Through a series of characterization,it is clear that Nb_0.9Ta_0.1S₂/2D-C₃N₄ presents higher photogenerated hole-electron pair separation efficiency compared to monomer 2D-C₃N₄.When the proportion of Nb_0.9Ta_0.1S₂ loading reach 15%,the composite has achieved the best activity,and the degradation RhB rate raises to 97%,which is50%higher than monomer 2D-C₃N₄.This work can degrade organic pollutants more effectively based on the g-C₃N₄ design,and proposes new insights and new strategies for the design of two-dimensional heterostructures.