Cocatalyst Control And Photocatalystic Performance Of Cd_1-xZn_xS Photocatalytic Materials

In recent years,the rapid depletion of resources and the excessive pollution of the environment have forced us to seek cleaner energy to replace existing energy.Among the many newly developed resources,solar energy has received widespread attention due to its wide coverage and unrestricted geographical conditions.Hence,many researchers have also worked to convert solar energy into directly usable energy.Photocatalytic water splitting has become an important branched field of catalysis due to its clean,non-polluting,low energy consumption and renewable characteristics.The photolysis of water to produce hydrogen is the easiest way to generate pollution-free energy.Designing efficient and practical semiconductor was the core influencing factors to stimulate the photocatalytic hydrogen generation.Recently,the semiconductor of Cd_1-xZn_xS has attracted wide attention in the field of photocatalysis due to its outstanding optical properties and suitable band gap.However,single-phase semiconductors still have urgent problems such as high recombination rates of their own electrons and holes.Thus,this thesis takes Cd_1-xZn_xS as the main research object and supports it with different co-catalysts to achieve the purpose of improving its final hydrogen production performance.The obtained samples were evaluated for the properties of hydrogen production by photolysis.The main research contents and results are as follows:?1?In this work,we used a convenient template synthesis method to hydrothermally synthesize all samples at low temperature.The three different template reagents and catalysts work in synergy with each other.Due to the different small amino molecules,morphology,and ability to inhibit recombination between charges,the final hydrogen production performance is significantly different.Under the condition of using precious metal Pt as a cocatalyst,the optimal hydrogen production rate of the synthesized catalyst Cd_0.75Zn_0.25S-TETA?X=0.25?T??under visible light was 7.17 mmol g^-1 h^-1,which was about 7 times that of Cd_0.75Zn_0.25S-EDA.Under single-wavelength light at 420 nm,the apparent quantum efficiency?AQE?of X=0.25?T?reaches 7.9%.?2?Exploring this content of this section on the premise that the amount of catalyst CdZnS-TETA?CZS-T?is halved,and noble metal Pt is no longer used as a promoter.Utilize the non-precious metal of NiSe₂ as a co-catalyst.The aim is to adjust the morphology and light absorption capacity of the co-catalyst and even inhibit its charge recombination rate to improve its photocatalytic activity.The properties of the synthesized catalyst were tested.The results show that the catalyst has the best performance when the loading is 14%by weight.After 5 hours of visible light irradiation,its H₂ production reached 19.83 mmol/g.The value was about 2.76 times of catalyst X=0.25?T??3?The alloy PtSn synthesized by in-situ photoreduction deposition method was directly supported on CZS-T to improve its performance.When only the precious metal Pt is cited as the co-catalyst,the yield is about 4.62 mmol g^-1 h^-1.After loading PtSn and continuously adjusting the ratio,the catalyst X=0.25?T?-PS4 has the best hydrogen production,and its yield is about 7.72 mmol g^-1 h^-1.