Preparation Of CdS-based Bulk Photocatalyst And Study On Photocatalytic Hydrogen Production Performance

In today’s society,energy shortages and environmental degradation are intensifying.,and it is imperative to develop new renewable and clean energy.Converting inexhaustible solar energy into clean,efficient,storable and transportable hydrogen energy is an effective way to achieve sustainable human development.Among them,nder solar radiation using a semiconductor as a photocatalyst to decompose water to produce hydrogen.that can efficiently convert solar energy into hydrogen energy for storage,has become a research topic that countries around the world attach great importance to.Among the widely studied semiconductor photocatalysts,cadmium sulfide（Cd S）has attracted extensive interest in recent decades due to its high utilization rate of sunlight.However,when Cd S is used alone,photogenerated carriers are easily recombined,resulting in low hydrogen production efficiency and severe photocorrosion,which greatly limits the use of Cd S.Therefore,researchers have modified Cd S by various methods such as structure and morphology control,loading co-catalysts,and compounding with semiconductors to slow down the recombination of photogenerated carriers and inhibit the phenomenon of photocorrosion,thereby improving its photocatalytic hydrogen production performance.However,in the currently reported Cd S-based photocatalytic hydrogen production system,the photocatalyst and the cocatalyst are usually synthesized separately,and further combination is required before application,and the process is complicated;most of the obtained semiconductor photocatalyst/cocatalyst hydrogen production system is in the form of powder,requires external stirring during use,and is not conducive to recycling after use,which limits its practical application.Aiming at the above challenges,this research is devoted to a novel photocatalyst preparation strategy,quasi-in situ preparation of Cd S-based bulk photocatalysts with excellent photocatalytic hydrogen production performance,convenient use and easy recycling,and its photocatalytic hydrogen production performance and the mechanism of hydrogen production.The details are as follows:（1）A series of cadmium sulfide-molybdenum sulfide composite bulk photocatalysts（a-MoS_x-Cd S/Ti）were prepared in situ on titanium mesh by one-step potentiostatic deposition method using titanium mesh（Ti）as the photocatalyst growth substrate.The bulk catalyst is convenient to use,easy to recycle,and exhibits excellent photocatalytic water splitting performance for hydrogen production.Under visible light irradiation,7%a-MoS_x-Cd S/Ti exhibited the best hydrogen evolution rate of 4476μmol g^-1h^-1.The optimum hydrogen production rate can be further increased to 17413μmol g^-1h^-1 by sputtering an appropriate amount of Pt particles on its surface.Its excellent photocatalytic hydrogen production performance can be attributed to the easy transfer of photogenerated electrons from Cd S to Cd S due to the close interfacial contact between a-MoS_x and Cd S and its excellent catalytic activity for hydrogen production when a-MoS_x is introduced as a cocatalyst.The hydrogen evolution active sites on a-MoS_x facilitate the efficient separation and transfer of photogenerated electron-hole pairs,and efficiently participate in the catalytic hydrogen evolution reaction.（2）Using titanium mesh as the photocatalyst growth substrate,a series of cadmium sulfide-nickel sulfide composite bulk photocatalysts（Ni S₂-Cd S/Ti）.The bulk catalyst is convenient to use,easy to recycle,and exhibits excellent photocatalytic hydrogen production performance.Under visible light irradiation,0.8%Ni S₂-Cd S/Ti exhibited the best photocatalytic hydrogen production rate of 2742μmol g^-1h^-1.Its excellent hydrogen production performance can be attributed to（1）the tight bonding between Ni S₂ and Cd S microrods,which is conducive to the separation and transport of photogenerated carriers,and（2）the Cd S-Ni S₂ microrod array is conducive to the increase of incident light.Sub-reflection,enhanced light absorption and utilization,and（3）the one-dimensional structure of Cd S microrods are beneficial to electron transport.（3）Using carbon cloth（CC）as the photocatalyst growth substrate,a series of cadmium sulfide-cobalt sulfide bulk photocatalyst（CoS₂-Cd S/CC）.The bulk catalyst is convenient to use,easy to recycle,and exhibits excellent photocatalytic water splitting performance for hydrogen production.Under visible light irradiation,1%CoS₂-Cd S/CC exhibited the best hydrogen evolution rate of 16608μmol g^-1h^-1.Its excellent hydrogen production performance can be attributed to（1）the tight bonding between CoS₂ and Cd S microrods,which is conducive to the separation and transport of photogenerated carriers（2）the Cd S-CoS₂ microrod array is conducive to the multiple incident light Reflection,enhanced light absorption and utilization（3）The one-dimensional structure of Cd S microrods is conducive to electron transport（4）The strong endothermic ability of carbon cloth leads to an increase in the local reaction temperature of the catalyst and enhances the rate of hydrogen production...