Influencing Mechanism Of Defects On Photocatalytic Performance Of Pure Graphene/Cuprous Oxide Composite

Semiconductor photocatalytic technology, which has been widely concerned by researchers in many countries, is an ideal technique for governing environmental issues. Highly efficient semiconductor photocatalytic materials are the important premise for realizing the application of semiconductor photocatalytic technology. And the correlational research has already become a new hotspot in material and chemical research.In the past few years, many highly efficient semiconductor photocatalytic materials have been discovered and applied in our life. Cu₂O semiconductor photocatalytic materials have become the keystone of research with the advantages of cheap, non-toxic, environmental friendly and high reaction activity. However, Cu₂O cannot bring its potential value because of its shortcomings, such as poor stability, narrow photoresponse, recovery difficulties, etc.With the large specific surface area, excellent electron conductivity and three-dimensional cross linking porous structure, the three-dimensional graphene foam has got much attention by materials scientists. At present, the main method for fabrication of a large area, controllable and high quality three-dimensional graphene is chemical vapor deposition?CVD?. The chemical vapor deposition uses porous foam metal, such as copper foam and nickel foam, as the catalyst substrate to synthesize a large scale of graphene. This method is simple and controllable. And different quality graphenes can be synthesized quickly and efficiently by this method. Compared with the GO and RGO, which was synthesized by chemical reduction method, the graphene prepared by CVD does not contain a lot of oxygenous groups, so it is convenient to reveal the role of graphene in the composite materials.This paper starts from improving the degradation activity of Cu₂O semiconductor photocatalytic, by combining Cu₂O with graphene foam effectively to overcome the shortcomings of Cu₂O in the application of photocatalytic materials and improve its photocatalytic degradation activity.The graphene foam is synthesized by using copper foam as catalyst and substrate, with hydrogen and methane as reaction gases, to get copper foam based graphene after high temperature reaction. The temperature and the flow rate of methane in CVD reaction are changed to prepare the graphene with different defects. Then the experiment is carried out by simply one step liquid phase reduction method, to prepare graphene/cuprous oxide composites.Experimental results show that when using methyl orange as the degradation dye, the temperature of CVD reaction is 1000 °C and the flow rate of methane is 7 sccm, the synthesized graphene /cuprous oxide composite shows the best photocatalytic degradation rate. Further sthdy show a closely relationship between the photocatalytic activity level of composite and the defect value of graphene. That is, only when the defective value of graphene in a certain range, will the prepared composites show higher photocatalytic efficiency under visible light. The spectrum test show that moderate graphene defect can adjust the morphology and grain size of Cu₂O paiticles, decreasing its bandgap and separating the photogenerated electron-hole pairs effectively, and hence promoting the photocatalytic activity.