Cadmium Sulfide-based Photocatalysts For Hydrogen Production: Synthesis And Regulation

Energy shortage and environment pollution are the eternal challenges facing humanity.Using semiconductors to convert infinite solar energy into chemical energy,could producing hydrogen energy through water splitting,and the clean hydrogen energy is considered as a dual-effect approach for solving both energy and environmental problems.Cd S is a kind of typical semiconductor with wide bandgap,which is widely used in photocatalytic hydrogen power generation.However,pristine Cd S is suffering from the low photocatalytic activity due to the rapid recombination of photoinduced electron-hole pairs in the bulk and photo-corrosion problems under the light irradiation.Besides,it has drawbacks of the complex synthesis procedures,the requirements of sophisticated equipment,and the toxicity,which makes it difficult to be widely applied.Based on this context,a series of studies are carried out in this paper based on Cd S semiconductor photocatalyst.First,towards the complex synthesis procedures of zero-dimensional Cd S,the decrease of the photocatalytic active site due to the easy agglomeration,and the recombination of photoinduced carriers in pure Cd S,a novel3D Mo S₂@Cd S@Ui O-66 nanostructures were obtained by a facile solvent-free approach applying a step-by-step strategy according to the size differences among those species.The core/shell configuration provided a suitable unit in size to easily equip defect rich Mo S₂nanosheets.The Ui O-66 Zr-MOFs used as a porous container to promote the dispersion of Cd S nanoparticles,resulting in the increase of active sites for photocatalytic reaction.The further enhanced photocatalytic activity for Mo S₂@Cd S@Ui O-66 could be attributed to the manufactured defect on the exposed edges of Mo S₂nanosheets,which perform as cocatalyst to accelerate the hydrogen revolution rate of photoinduced electrons on its surface.Besides providing extensive migration routes over photogenerated electrons,more importantly,remarkably,Ui O-66 create ample time and sites for accelerating consumption of the isolated photogenerated holes with the sacrificial agent,resulting in alleviating photo corrosion reaction,and further realizing the promotion of photocatalytic efficiency and photostability simultaneously.Besides,this work highlights the potential application of core/shell configuration in photocatalytic hydrogen evolution.On this basis,we developed the solvent-free synthesis strategy of Cd S based semiconductors.To alleviate the toxicity of pure semiconductor Cd S system,as well as to solve the problem of the scarcity of traditional noble metal cocatalyst,we have designed a kind of green synthetic strategy which is more facile and economical.In virtue of the charge difference between Cd_xZn_1-xS and MXene,the Cd_xZn_1-xS/Ti₃C₂MXene composite photocatalyst was successfully synthesized by a one-step solid-phase method and carried out the related studies on its performance for photocatalytic hydrogen production.It is illustrated that the Cd Zn S/Ti₃C₂MXene nanocomposites exhibit maximum hydrogen production rate of 15035.81μmol g^-1h^-1,which was 2.7 times as high as that of pristine Cd Zn S,when the content of the single-layer 2D Ti₃C₂MXene is 1.0 wt%,revealing that Ti₃C₂MXene nanosheets can significantly improve the photocatalytic hydrogen production activity of Cd Zn S.The exceptional performance of Cd Zn S/Ti₃C₂MXene might be ascribed to the superior electrical conductivity and unique 2D layered structure of hydrophilic Ti₃C₂MXene,which facilitated the separation of photoinduced electron-hole pairs.This work laid the experimental foundation and theoretical explanation for the green controllable preparation of high-quality photocatalyst for hydrogen production without noble metal loading.The above work has carried out a relatively systematic study on how to enhance the hydrogen production activity of Cd S based photocatalyst,hoping to provide some references for their further research in the field of photocatalysis.