Study On Morphology Regulation And Photocatalytic Performance Of CdS Photocatalyst

CdS has been widely studied because of its reasonable energy band structure,good visible light response,and high photocatalytic activity.The photocatalytic activity of CdS depends largely on its size,shape,and crystal structure.Aiming at the problem that the photogenerated carriers existing in CdS are easy to recombine,this study improves the photocatalytic performance of CdS photocatalyst by morphological adjustment and modification.Details can be summarized as follows:?1?The CdCO₃ cubic structure was firstly synthesized by hydrothermal method.Then CdS quantum dots?QDs?were in-situ deposited on the CdCO₃ to form CdCO₃/CdS QDs composite photocatalyst to explore its photocatalytic hydrogen production performance.Physical characterization results show that cubic CdCO₃ consists of nanoflake structures,and CdS QDs are uniformly dispersed on the surface of CdCO₃ nanoflakes to form heterostructures.Under visible light irradiation,the photocatalytic H₂ production rate of CdCO₃/CdS QDs photocatalyst is 1.93 mmol·h^-1·g^-1.The cubic CdCO₃ can provide a large number of activity sites for CdS QDs,which is conducive to the photocatalytic hydrogen production process.?2?The experiment first prepared a novel nano-flowered Co₉S₈ hierarchical structure by solvothermal method without template,and further deposited CdS QDs particles on its surface.The results show that CdS/Co₉S₈ heterojunction photocatalyst has a significantly improved photocatalytic hydrogen production performance.Under visible light irradiation,the photocatalytic hydrogen production rate of CdS/Co₉S₈ can reach 11.60 mmol·g^-1·h^-1,which is 13.65 and 55.24 times of that of CdS and Co₉S₈ photocatalysts,respectively.The synergism of the hierarchical structure and the Z-scheme heterojunction system makes the photocarriers transfer to the surface of photocatalyst quickly and effectively,which accelerates the process of the photocatalytic hydrogen production.?3?A thin film composed of CdS nanoparticles was prepared in the experiment.First,a CdS seed layer is coated on the etched Ti wafer by the seed method,and then a CdS film is grown by the hydrothermal method.The results show that when the solvent is hydrogen peroxide and the number of hydrothermal cycles is three times,the CdS film has the best photoelectrochemical performance,and a photocurrent of about 4.9 mA/cm²?0 V vs Ag/AgCl?is obtained under 100 mW/cm² simulated sunlight.As the number of hydrothermal increases,the CdS nanoparticles further mature,and the CdS crystals continue to increase,which will limit the rapid and effective transport of photo-generated carriers.