Preparation Of Cadmium Sulfide Based Composite Photocatalysts And Study On Their Photocatalytic Properties

With the rapid development of society, energy and environmental pollution issueshave become important topics. The design and synthesis of photocatalysts forhydrogen production and pollutant photodegradation are the driving force and thebasis of development of photocatalysis chemistry. In particular, photocatalytic watersplitting for hydrogen production is one of promising ways by solar light energywhich have been considered to be attractive methods to resolve environmentalremediation and renewable energy production. In the past few decades, numerousphotocatalysts have been proposed, but only a few effective photocatalystsresponsive to visible-light irradiation have been reported. Therefore, newvisible-light sulfide photocatalysts with high efficiency for hydrogen production areneeded to meet the requirements of future energy and environment.In this paper, the structures and morphologies of the obtained compositephotocatalysts were characterized by XRD, UV-Vis, SEM, XPS, EDX, BET, TEM,GC-MS, fluorescence spectrum and photocatalytic activity test, respectively.Nanocrystals with size of5-10nm embedded in CdS/ZnS/In₂S₃microsphereshave been successfully synthesized by sonochemistry method. Closer observationsindicate that the sample is composed of a large quantity of uniform microsphereswith size of0.5-1μm. The photocatalytic activities of CdS/ZnS/In₂S₃for watersplitting from aqueous solutions containing sacrificial reagents （SO₃2–and S2–）, areinvestigated under visible-light irradiation （λ>400nm）. The rate of CdS/ZnS/In₂S₃photocatalytic hydrogen yield reached8.1mmol·h^-1·g^-1and exhibited a highapparent yield （40.9%at420nm） of hydrogen production without co-catalysts.Nanocrystals with size of5-10nm embedded in CdS/In₂S₃/CoS nanoparticleshave been successfully synthesized by sonochemistry method. The photocatalyticactivities of CdS/ZnS/In₂S₃for water splitting without co-catalysts are investigatedunder visible-light irradiation （λ>400nm）. Photocatalytic conditions for hydrogenproduction have been investigated, considering the factors such as the reaction time,the amount of photocatalyst, the amount of CdS and the concentration of sacrificialreagents. In particular, the rate of CdS/In₂S₃/CoS photocatalytic hydrogen yieldreached4.53mmol·h^-1·g^-1and exhibited a high photocatalytic activity （23.76%at420nm） of hydrogen production.The nanoporous MoO₃/CdS core/shell composite photocatalysts have beensuccessfully synthesized by sonochemistry method without using any templates orsurfactants. The CdS nanocrystals with size of5-10nm are embedded in theMoO₃/CdS nanosphere, while the MoO₃particles are located in the core and theCdS particles are located in the shell. The sizes of CdS shell are estimated to be 95-105nm. The photocatalytic activities of MoO₃/CdS core/shell photocatalytic forwater splitting without co-catalysts are investigated under visible-light irradiation（λ>400nm）. The rate of MoO₃/CdS photocatalytic hydrogen yield reached5.25mmol·h^-1·g^-1and exhibited a high photocatalytic activity （28.86%at420nm） ofhydrogen production.