Modification Of WO₃/g-C₃N₄ Composite Photocatalyst And Study On Its Photocatalytic Performances

Graphite carbon nitride?g-C₃N₄?and tungsten trioxide?WO₃?are two typical visible-light-induced photocatalysts which are frequently used in the photocatalytic reaction for their good properties such as easy preparation,non-toxicity,stability,etc.The combination of the forementioned photocatalysts will definitely improve the photocatalytic activity.Furthermore,Morphology-controlling and coating cocatalysts willgreatly inhibit the recombination of photogenerated electrons and holes,which will improve the photocatalytic efficiency.The main research contents and achievements of the paper are chiefly as follows:?1?g-C₃N₄ nanosheets?g-C₃N₄ NS?were prepared by thermal oxidation etching method,WO₃ nanosheets?WO₃ NS?were fabricated with the aid of P123 lamellar micelles,and WO₃ NS/g-C₃N₄ NS with different composite ratios were prepared by calcining method.The microstructure,morphology and optical properties of the samples were characterized by XRD,SEM,FT-IR,UV-Vis DRS and XPS.The performance of WO₃ NS/g-C₃N₄ NS was evaluated by photocatalytic degradation of RhB solution under simulated sunlight irradiation.The optimal compound ratio of WO₃ NS and g-C₃N₄ NS was 20 wt%of WO₃ NS,and its degradation rate was 4.70times and 1.72 times than that of pure g-C₃N₄ NS and WO₃/g-C₃N₄ NS,respectively.The mechanism of the separation of photogenerated electrons and holes was investigated as a Z-scheme system through the free radical trapping experiment.?2?Composite photocatalyst of WO₃ particles and g-C₃N₄ NS was prepared by calcining method.And then the Ag/WO₃/g-C₃N₄ NS with different contents of Ag and MnO_x/WO₃/g-C₃N₄ NS with different contents of MnO_x were prepared by photo-deposition of Ag and MnO_x onto the surface of 20 wt%WO₃/g-C₃N₄ NS,respectively.The microstructure,morphology and optical properties of the samples were characterized by XRD,TEM,FT-IR and UV-Vis DRS.The optimal loading of Ag and MnO_x were both 1 wt%,which was determined by photocatalytic degradation of RhB solution under simulated sunlight.?3?Ag-MnO_x/WO₃/g-C₃N₄ NS composite photocatalyst that modified by dual-cocatalysts was prepared by photo-deposition of Ag and MnO_x onto the surface of20 wt%WO₃/g-C₃N₄ NS in turn.The microstructure,morphology and optical properties of the samples were characterized by XRD,TEM,FT-IR and UV-Vis DRS.In the experiment of photocatalytic degradation of RhB,the degradation rate was 4.80 times and 1.87 times that of pure g-C₃N₄ NS and WO₃/g-C₃N₄ NS,respectively.Compared with samples prepared by impregnation which non-selectively coated dual-cocatalysts,the samples prepared via photodeposition showed higher photocatalytic activity.