Preparation Of Metal-loaded 2D Nanosheet Photocatalysts And Their Applications In Visible-light Driven Photocatalysis

Two-dimensional（2D）materials,with large surface area and flexible electronic structure,have been considered to play roles for the application of semiconductor photocatalysis.Meanwhile,the adding of metal for semiconductor composites has been found to promote the generation of electron-hole pairs and enhance the photocatalytic activity.In this academic dissertation,three types of metal loaded nanosheets materials have been prepared and their structure and photocatalytic properties were studied.The as-prepared photocatalysts were characterized by various analytical methods and their photocatalytic properties were tested.1.A novel Ag/CoS nanocomposite has been successfully synthesized by attaching Ag nanoparticles on the surface of CoS nanosheets with the assistance of light illumination.The microstructure and properties of the as-prepared samples were characterized by XRD,XPS,TEM,UV-Vis DRS.etc.The results showed that Ag nanoparticles were successfully loaded on the surface of CoS nanosheets and the light absorption of nanocomposites was greatly advanced owing to the surface plasmon resonance（SPR）of Ag nanoparticles.The photocatalytic activity of Ag/CoS photocatalysts was evaluated by the decomposition of methylene blue（MB）under visible light.The 2% Ag/CoS sample presented the optimal photocatalytic activity with the degradation rate of 72.7%,which was 2 times higher than pristine CoS.Additionally,the Ag/Co S composite photocatalysts presented good stability.It was found that the main reactive species in the photodegradation of MB was superoxide anion.2.The ultrathin KCa2Nb3O10 nanosheets were synthesized by calcination and exfoliation method.The Au/KCa2Nb3O10 composites were prepared by depositing Au nanoparticles on the surface of KCa2Nb3O10 nanosheets through deposition-precipitation method.The microstructure and properties of the as-prepared samples were characterized by XRD,XPS,TEM,UV-Vis DRS.etc.The results showed that Au nanoparticles were successfully loaded on the surface of KCa2Nb3O10 nanosheets and the nanocomposites presented visible-light response owing to the SPR of Au nanoparticles.The results of the degradation of tetracycline hydrochloride（TC）showed that the 2% Au/KCa2Nb3O10 composite exhibited the highest degradation rate.The photocatalytic mechanism of Au/KCa2Nb3O10 photocatalysts revealed that the main reactive species in the process of photodegradation were hole and superoxide anion.3.The Cu/g-C₃N₄ nanocomposites were prepared by co-heating method with ethylene glycol.The microstructure and properties of the as-prepared samples were characterized by XRD,XPS,TEM,FT-IR.etc.The results showed that Cu nanoparticles were successfully attached on the surface of g-C₃N₄ nanosheets.The photocatalytic activity of Cu/g-C₃N₄ photocatalysts was evaluated by the hydrogen production over water splitting under visible light.The results showed that the introduction of Cu could effectively promote the separation of photogenerated electron hole pairs and thus enhance the photocatalytic performance of hydrogen production.