Controlled Synthesis Of G-C₃N₄-based Nanostructures And Research Of Photocatalytic Reduction Of CO₂

Photocatalytic technology is the application of solar energy to produce chemical energy.The development of stable,efficient,and inexpensive visible-light driven catalysts is considered as a key factor in the widespread use.Graphite-phase carbonized nitrogen?g-C₃N₄?has become a hot topic due to its many advantages.However,the photocatalytic performance of pure g-C₃N₄ photocatalyst is limited due to its low efficiency of photoelectron-hole pair separation.According to the transfer mechanism of the photogenic charge between g-C₃N₄ and the coupling components,this study combines heterogeneous junction,nanometer size,core-shell structure,oxygen vacancy,noble metal effect and template method to explore the synthesis strategies of two g-C₃N₄-based heterogeneous junction catalysts and their visible light catalytic performance of CO₂ reduction.The main research contents of this thesis are as follows1.Au@g-C₃N₄/SnS yolk-shell Z-scheme photocatalysts are fabricated.The L-cysteine can offer the amine groups to enhance carbon dioxides adsorption capability.Meanwhile,the unique yolk-shell structure enhances the availability ratio of light.The application of small amount of noble metal cocatalysts and the large BET surface areas are also benefit for the enhanced photocatalytic activities.This Z-scheme photocatalytic reduction mechanism of Au@g-C₃N₄/SnS performs valuable functions in the reaction,making the Au@g-C₃N₄/SnS?SnS 41.5%?sample have a good performance of photocatalytic reduction of CO₂ and good stability.2.Hollow heterostructured g-C₃N₄@CeO₂ photocatalysts with rich oxygen vacancies are controllable designed.The photocatalytic activity of the sample is improved by increasing the CO₂ adsorption capacity of the sample,increasing the specific surface area active site,improving the efficiency of light utilization,constructing defects of oxygen vacancy and conventional type ? heterojunction.The synergetic effect and oxygen vacancies of g-C₃N₄@CeO₂ play the major role in the process of CO₂ reduction.Therefore,the novel photocatalysts,g-C₃N₄@CeO₂?CeO₂49.7 wt%?,exhibit a remarkable reduction performance for CO₂ reduction under visible light irradiation and the highest yields of CH4,CH3OH and CO.The core-shell structure Au@g-C₃N₄/SnS and g-C₃N₄@CeO₂ heterostructure photocatalysts prepared in this paper can effectively convert CO₂ into clean fuel and can be used for energy storage and conversion as well as environmental treatment...