Preparation Of Au NR@Cu₂O-Au NP Nanocomposites And Study On Photocatalytic Performance

Cuprous oxide nanoparticles(Cu2O NPs),as a low-cost,environment-friendly,P-type semiconductor that responds to visible light,have attracted much attention in the field of photocatalysis.However,due to its low photo-generated electron-hole separation efficiency,the application of pure Cu2O NPs is seriously hampered.Combining with metals is an effective method to enhanced the performance of bare Cu2O photocatalyst.In this thesis,the noble metal Au with LSPR effect is selected to be compounded with Cu2O.A controllable internal and external synergy Au(R)@Cu2O-Au(P)nano-composite photocatalyst was prepared,while its photocatalytic degradation of organics and photocatalytic reaction mechanism were studied.The main research contents and results are as follows:The seed-heterogeneous nucleation and self-reduction method were used to prepare a sample of gold nanorods coated with Cu2O on the surface of gold nanoparticles,which named as Au(R)@Cu2O-Au(P).The pure Cu2O,Cu2O-Au(P),Au(R)@Cu2O,and Au(P)Cu2O-Au(P)were prepared as comparative samples using the same method.XRD,SEM,TEM,XPS,etc.were used to characterize the structure,morphology,and physicochemical properties of the prepared samples,and perform photocatalytic degradation of methyl orange(MO)dyes.Under the same conditions,the rate of photocatalytic degradation showed as:Au(R)@Cu2O-Au(P)>>Cu2O-Au(P)>Au(R)@Cu2O>Cu2O,which the degradation amounts were 93.5%,31.3%,103%,and 6.1%,respectively.Meanwhile,the prepared photocatalysts showed good repeatability.The structure and composition of Au(R)@Cu2O-Au(P)composites were optimized.It was found that the morphology of the core Au particles,the thickness of the Cu2O shell layer,and the element of surface-loaded metal directly effect their photocatalytic degradation performance.In this thesis,the photocatalytic reaction mechanism is carried out by characterizing the absorption spectrum range of the sample,photoelectrochemical test,photocatalytic degradation quenching experiment,and three-dimensional-time domain finite difference(3D-FDTD)simulation,combined with its photocatalytic degradation performance results.A "push-pull"synergetic effect of the Au(R)and Au(P)was found to improve the transfer and separation of charge carriers from the bulk to the surface of Cu2O.Furthermore,the light beyond Cu2O's absorption range can penetrate the shell(Cu2O)and be utilized by the Au(R)core via its localized surface plasmon resonance effect(LSPR)to inject hot electrons to the conduction band of Cu2O for photocatalytic reaction.Through the adjustment of the material structure and components,the research achieved "push-pull" synergistic enhancement of photocatalytic degradation performance,which has reference value for the design of efficient ternary or multiple photocatalysts.