| Owing to the serious environmental pollution,the detection and degradation of organic pollution have attracted researcher's wide attention.How to degrade organic pollution while detecting pollutants has become an important issue that needs to be solved.Surface-enhanced Raman scattering,a phenomenon of Raman scattering enhancement,is caused by plasmon resonance interaction between molecules adsorbed on the surface of metal nanostructures and metal surfaces,which is a very effective technique for detecting Raman signals in the spectrum.In addition,photocatalytic degradation has been attracting attention due to its rapidity,simplicity,and energy saving.It is of great theoretical and practical value to study with high SERS substrate sensitive and photocatalytic performance.In this thesis,copper oxide and silver-copper oxide nanocomposite were prepared.And their SERS and photocatalytic performance were studied.The Ag nanoparticles supported on the surface of the copper oxide can make the composite have a rough surface and promote a certain amount of"hot spots"for the improving the SERS effect.At the same time,metal Ag as a surface defect can capture electrons from the metal oxide conduction band,reduce electron-hole recombination,and then improve photocatalytic performance.This material with both SERS activity and photocatalytic activity,can detect pollutants and degrade pollutants,which greatly reduces the research cost.The main results are as follows?1?Solid Cu2O and hollow Cu2O cubes were prepared by room temperature liquid phase reduction method.The SERS and photocatalytic properties of Cu2O with different morphologies were studied.The obtained solid Cu2O is used as the SERS substrate,and the enhancement factor for Rhodamine 6G?R6G?can reach 1.97×107.However,the enhancement factor for methylene blue?MB?is not obvious.At the same time,the material also showed good photocatalytic performance.With Solid Cu2O or hollow Cu2O as photocatalyst,the degradation of MB in the presence of light and H2O2 can reach over90.34%and 90.40%within 3.5 h,respectively,the degradation of R6G can reach 91.59%and 91.89%,within 2 h,respectively.The cyclic stability of solid Cu2O SERS substrate was also studied.After four cycles,the enhancement factor of the substrate to R6G still retains at9.68×105.?2?On the above basis,solid Ag-Cu2O and hollow Ag-Cu2O nanocomposites were prepared by photochemical reduction.Solid Ag-Cu2O SERS substrate to MB can reach 4.08×105,and the detection limit can reach 10-8 mol/L.The enhancement factors for R6G are up to 3.64×107,and the detection limit is 10-9 mol/L.In the presence of light and H2O2,the degradation of MB by solid Ag-Cu2O in 3.5 h was 94.91%.The degradation of R6G in 2 h was 94.60%.That after six reuse cycles,the enhancement factor of the solid Ag-Cu2O substrate to MB still retains at 7.09×103,to R6G still retains at 7.09×103.Hollow Ag-Cu2O SERS substrate to MB can reach 1.10×106,and the detection limit can reach 10-8mol/L.The enhancement factors for R6G are up to 2.59×107,and the detection limit is 10-9mol/L.In the presence of light and H2O2,the degradation of MB by hollow Ag-Cu2O in 3.5h was 90.65%.The degradation of R6G in 2 h was 96.50%.That after six reuse cycles,the enhancement factor of the hollow Ag-Cu2O substrate to MB still retains at 2.58×104,to R6G still retains at 8.94×104.?3?Ag-CuO nanocomposites were prepared based on porous CuO with a photochemical reduction method.The obtained Ag-CuO nanocomposites show bifunctions.They can not only be used as surface-enhanced Raman scattering?SERS?substrates,providing a enhancement factor of 3.86×107 towards R6G and 7.08×107 towards p-aminothiophenol,but also can be used as an effective photocatalyst to degrade R6G,methyl orange?MO?and MB with H2O2 under light irradiation.The Ag-CuO nanocomposite can degrade 96.7%of R6G within 2 hours,degrade 91.8%of MO within2.5 hours and degrade 93.7%of MB within 3 hours.It is believed that the porous microstructure provides more“hot-spots”for SERS and active sites for photocatalytic process,inducing excellent performance.Due to the bifunctions,reusing of the Ag-CuO SERS substrate was demonstrated with the assistance of light irradiation cleaning process.After eight reuse cycles,the enhancement factor of the substrate to R6G still retains at 1.45×105.The experimental results show that the dual-functional composite material can be used as both a SERS substrate and a photocatalyst.Through the photocatalytic process,it can promote the cleaning and recycling of SERS substrates,realize rapid detection of organic pollutants and effective photocatalytic degradation. |
PDF Full Text Request