Preparation Of CdS-based Photocatalytic Materials And Photocatalytic Performance Study

In recent years,semiconductor photocatalysis technology,as an effective strategy,has attracted the attention of many research teams due to its ability to alleviate the energy crisis and environmental pollution.CdS has been widely studied due to its suitable band gap,excellent light absorption range and sufficient driving force for the photocatalytic hydrogen evolution reaction.However,CdS has high recombination efficiency of photogenerated electron-hole pair and slow migration rate of photogenerated carriers,which greatly restricts the photocatalytic performance of CdS.Aiming at the above-mentioned problems affecting the photocatalytic performance,this paper studies the modification of CdS by improving the separation efficiency of photogenerated carriers and reducing the internal resistance to promote the transfer rate of photogenerated carriers,thereby improving the photocatalytic performance of CdS.The main results are as follows:C₃N₅,fishbone CdS and fishbone CdS/C₃N₅（CC）with different composite ratios were prepared by solid-phase sintering and hydrothermal methods.The results of photocatalytic degradation of methyl orange and photocatalytic hydrogen evolution reaction showed that fishbone CdS/C₃N₅ had better photocatalytic performance than fishbone CdS and C₃N₅.XRD and SEM results showed that a stable heterostructure was formed between fishbone CdS and C₃N₅.The results of FT-IR and Raman spectroscopy indicated that the fishbone CdS and C₃N₅ had a strong interface effect.Electrochemical results show that the CC samples have lower transport impedance,longer carrier lifetime and higher carrier concentration.Furthermore,combined with theoretical calculations,a photogenerated carrier transport mechanism（type-II heterojunction）between fishbone CdS/C₃N₅ is proposed.CdS,ZnS and Cd_0.5Zn_0.5S solid solution photocatalysts were prepared by hydrothermal method.According to the photocatalytic degradation of acid fuchsin and methyl orange and the results of hydrogen evolution experiments,it can be found that Cd_0.5Zn_0.5S solid solution has better photocatalytic performance than CdS and ZnS.The PL spectroscopy results show that the photo-generated carrier recombination efficiency inside Cd_0.5Zn_0.5S decreases.Electrochemical results show that Cd_0.5Zn_0.5S exhibits lower carrier transport resistance,increased carrier lifetime,enhanced carrier concentration,and reduced overpotential.The exciton binding energies of CdS,ZnS and Cd_0.5Zn_0.5S were calculated using the quasiparticle approximation method,which were 0.47 e V,0.22 e V and 0.15 e V,respectively.The results show that the exciton binding energy in Cd_0.5Zn_0.5S is lower,and the photo-generated electrons and photo-generated holes are easier to separate.