Preparation And Properties Of Photocatalytic Materials Based On ZnCdS

The synchronization of economic prosperity and a better life, environmental protection and energy regeneration have gradually become two major themes that cannot be ignored in today’s society.Various chemical factories have also risen rapidly,causing certain environmental pollution to the surrounding environment.Therefore,as a green technology,photocatalytic technology has gradually entered the attention of human beings.Photocatalysis has the outstanding advantages of being environmentally friendly,simple and easy to operate,using water as a solvent,and not forming any secondary pollutants.ZnCdS is a ternary sulfide solid solution with the advantages of tunable forbidden band,abundant elemental composition,and high stability.Changing the ratio of Zn to Cd can tune the band gap to improve the photocatalytic performance.However,the functions of a single catalyst are always limited,and it is of great significance to develop more efficient photocatalysts.In this paper,other materials are mainly used to combine with ZnCdS.This paper focuses on the following research.In this paper,zinc acetate dihydrate（Zn（CH₃COO）₂·2H₂O）was used as Zn source,cadmium acetate dihydrate（Cd（CH₃COO）₂·2H₂O）was used as Cd source,thiourea（CH₄N₂S）was used as S source,and water（H₂O）as solvent,Zn_0.2Cd_0.8S was synthesized by a simple one-pot hydrothermal method.On the basis of Zn_0.2Cd_0.8S,co-catalyst carbon dots（CDs）were selected to be doped into Zn_0.2Cd_0.8S.When the addition amount was 0.26 mg（3.25g/L）,the photocatalytic performance of Zn_0.2Cd_0.8S@CDs was the best.Through the degradation evaluation test,within 2 hours of illumination,adding 30 mg of the catalyst,the degradation rate of Zn_0.2Cd_0.8S to Rhodamine B（Rh B）was59.60%,and the degradation rate of Zn_0.2Cd_0.8S@CDs composite catalyst to Rh B was 71.36%.When the amount of composite catalyst reached 50 mg,the degradation rate of Rh B increased to 79.35%.Finally,the photocatalytic degradation mechanism of the Zn_0.2Cd_0.8S@CDs composite was explored.Secondly,ZIF-67 with unique structure and Zn_0.2Cd_0.8S were used to form a composite catalyst.Electrochemical tests show that when the addition amount of ZIF-67 is 80 mg,Zn_0.2Cd_0.8S@ZIF-67 has the best photocatalytic performance.When the content of Zn_0.2Cd_0.8S@ZIF-67 composite catalyst was 30 mg,the degradation rate of Rh B increased to 77.85%within 2 h of illumination.When the addition amount of composite catalyst reaches 50 mg,the degradation rate of Rh B by Zn_0.2Cd_0.8S@ZIF-67 composite catalyst reaches 98.40%.Radical trapping experiments showed that·O₂^-played a major role in the photocatalytic degradation of Rh B by Zn_0.2Cd_0.8S@ZIF-67.Finally,it is deduced that the Zn_0.2Cd_0.8S@ZIF-67 composite catalyst conforms to the Z-type photocatalytic system.