Controlled Synthesis And Photocatalytic Properties Of Ordered Mesoporous Cd-based Sulfide Heterocomposites

The current speed of global energy consumption urgently requires the development of new alternative energy sources.Visible light photolysis of water for hydrogen production has become a priority strategy to solve global energy and environmental problems because of its ability to convert solar energy into efficient and clean hydrogen energy.The design and synthesis of catalytic materials has become the key to ensure the smooth implementation of this strategy.In this thesis,the cadmium-based sulfide with visible light responsiveness is used as the main material,and the active sites are increased by the method of mesoscopic structure control and heterocomplexation,which promotes the separation of photogenerated charges,and comprehensively utilizes the dual control of structure and composition to improve the photolysis of aquatic hydrogen performance the material.First,a series of ordered mesoporous CdS with different mesostructures were prepared using the nanocasting method.0D MoS2 quantum dots were successfully synthesized by the hydrothermal synthesis method,and the phase of MoS2 quantum dots was regulated by changing the hydrothermal synthesis temperature.0D/3D-MoS2/CdS multidimensional heterostructure was synthesized by using OD MoS2 quantum dots to decorate the surface of ordered mesoporous CdS framework by ultrasonic self-assembly.The comprehensive use of XRD,BET,TEM,Raman and other characterization methods combined with the photocatalytic hydrogen production results show that the MoS2 quantum dots synthesized at a hydrothermal temperature of 180℃ have more 1T phases and better dispersion,ensuring the synthesis of multi-dimensional heterogeneity.MoS2/CdS has better photolysis water performance for hydrogen production.More importantly,CdS-40 with larger pore size and specific surface area can better disperse MoS2 quantum dots and provide more active sites,thereby showing more excellent performance of photohydrogen production from water splitting.Under the optimal loading conditions,the synthesized multidimensional heterogeneous MoS2/CdS-40 has a hydrogen production rate of up to 22.13 mmol g-1 h-1,which is 73.76 times that of ordered mesoporous CdS-40.Secondly,the ordered mesoporous ZnS/Cd0.64Zn0.36S heterocomposite was constructed by a secondary filling method based on the previous research of the research group on the ordered mesoporous cadmium-based solid solution Cd0.64Zn0.36S as a high-efficiency photocatalyst for water splitting.The effects of ZnS filling amount and Cd0.64Zn0.36S filling ratio on the photocatalytic hydrogen production performance were systematically studied.The results show that the ordered mesoporous ZnS synthesized with a lower filling amount has a larger specific surface area,and when the molar ratio to Cd0.64Zn0.36S reaches 1:1.5,it has the best photogenerated charge separation efficiency and the highest photocatalytic hydrogen production performance.The optimal hydrogen production rate of the synthesized ordered mesoporous ZnS/Cd0.64Zn0.36S heterocomposite reaches 18.04 mmol g-1 h-1,which is 1.97 times that of the single ordered mesoporous Cd0.64Zn0.36S.