Study On The Properties Of Cucurbit[n]urils Modified Cadmium Sulfide Composite Catalyst

This thesis aims to synthesize high-efficiency Q[n]/CdS-Ag₂S and Q[n]/CdS-MoS₂composite catalysts with potential applications value by using cucurbit[n]urils?Q[n]?recombination and narrow band gap semiconductor doping.CdS is widely used in photocatalyst research because of its unique photoelectrochemical properties.However,under light,the photo-generated electron-hole pairs of cadmium sulfide are easily recombined,which will affect their photocatalytic efficiency.Therefore,using effective methods to suppress the recombination of photogenerated electron-hole pairs in the photocatalytic process is an urgent problem to improve the photocatalytic performamce of the catalyst.CdS,narrow band-gap semiconductors and compounding with organics are important research directions for photocatalysts.Based on the pumpkin-shaped special structure of cucurbit[n]urils,polar ports,non-polar cavities and positive outer walls can coordinate with metal ions,include inclusion and hydrogen bond,and so on.In this paper,Q[n]is used as an organic composite agent,and the chemical precipitation method and hydrothermal method are used to design and synthesize Q[n]/CdS-Ag₂S and Q[n]/CdS-MoS₂series composite catalysts in order to obtain highly efficient catalytically active composite catalysts.The main research contents are as follows:1.Synthesis of a series of cucurbit[n]urils composite and Ag₂S-doped cadmium sulfide composite catalysts?Q[n]/CdS-Ag₂S?by chemical precipitation.Using CH₃CSNH₂?TAA?as the sulfur source and cucurbit[n]urils as the complexing agent,the effects of different Ag₂S doping amounts and cucurbit[n]urils on the morphology and photocatalytic performance of the product were investigated.The products were characterized by FT-IR,XRD,XPS,PL,SEM,TEM,and HRTEM,and the catalytic effect of composite catalyst Q[6]/CdS-Ag₂S on rhodamine B?Rh B?,methine blue?MB?and crystal violet solution was investigated.The experimental results showed that the Q[6]/CdS-Ag₂S composite catalyst can better degrade the dye Rh B.The Q[6]/CdS-Ag₂S compound catalyst obtained with 20%Ag₂S doping amount has the best photocatalytic effect on Rh B solution.2.Hydrothermal synthesis of a series of cucurbit[n]uril composite and MoS₂doped cadmium sulfide composite catalysts?Q[n]/CdS-MoS₂?.Using Na₂Mo O₄·2H₂O as the source of molybdenum and cucurbit[n]urils?Q[n],n=6,7,8?as the complexing agent,the effects of different sulfur sources?thioacetamide,thiourea,L-cysteine?on the morphology and catalytic properties of the products were investigated.FT-IR,XRD,XPS,SEM and other characterization methods were used to characterize the product,and the catalytic effect of Q[6]/CdS-MoS₂composite catalyst on methylene blue?MB?,rhodamine B?Rh B?and crystai violet solution was investigated.The experimental results showed that CdS-MoS₂and Q[6]/CdS-MoS₂showed adsorption performance when thioacetamide and L-cysteine are used as sulfur sources,and the product synthesized with thioacetamide as sulfur source has the better adsorption effect on MB.And when thiourea was used as the sulfur source,the product exhibited photocatalytic performance,and the photocatalytic degradation of MB with Q[6]/CdS-MoS₂composite catalyst was the best.The use of cucurbit[n]urils promoted the separation of photogenerated electron-hole pairs in Q[6]/CdS-Ag₂S.By regulating the main factors affecting its properties,Q[6]/CdS-Ag₂S and Q[7]/CdS-MoS₂composite catalyst with high catalytic activity was obtained.