Preparation And Applications Of Two-dimensional Ordered Noble Metal Nanoparticles Arrays

Noble metal nanoparticles have been widely used in biochemical analysis,pollutant detection and electrochemical catalysis because of their large specific surface area,unique optical properties and good catalytic activity.However,the noble metal nanoparticles prepared are mostly dispersed and randomly distributed,resulting in poor signal sensitivity and stability in application,which is not conducive to practical application.Therefore,we proposed a facile strategy for fabricating two-dimensional solid and porous metal nanoparticles array in this paper.Complementary to diffraction from arrays by localized surface plasmon resonance?LSPR?of noble metal nanoparticles,and combine with the regularity of the array,which can significantly improve detection performance and stability as a sensor or used surface enhanced Raman scattering?SERS?substrate,and promote the practical application of noble metal nanoparticles.Using polystyrene?PS?monolayer colloidal crystal microspheres as the template,Au films were sputtered on the surface of PS microspheres by magnetron sputtering method,and a large area??cm²?periodic ordered Au nanoparticle array was obtained by heat treatment.Based on the sensitivity of the LSPR peak and diffraction peak to the surrounding dielectric environment,the LSPR peak and diffraction peak are shift in the extinction spectrum to detect the sensitivity of different solvents.It solves the problem that the shift of LSPR peak is small and difficult to detect.The results show that the LSPR peak and diffraction peak gradually redshift with the increase of refractive index around the Au nanoparticle array.Compared to the LSPR peaks,the diffraction peaks are more sensitive.The effect of array periodicity on sensitivity is further studied.The results indicate that,in the same solvent,with the increase of the period,the shift of the LSPR peak decreases first and then increases,while the shift of the diffraction peak of the same order increases.The ordered array of Au nanoparticles prepared was used as the template,and a layer of Ag film was deposited by magnetron sputtering,the Au-Ag alloy nanoparticle array was obtained by heat treatment in a mixture of N₂and H₂.And the porous Au-Ag alloy nanoparticle array was prepared by etching with HNO₃solution.It has a hydrophobic surface after a layer of Au nanofilm is deposited on the ordered array surface.Based on the hydrophobic surface of porous Au-Ag alloy nanoparticle array,and high density active SERS"hot spots"generated by porous particles,realized the rapid SERS detection of 4-ATP and malachite green molecules,which solved the problem that the SERS substrate needed to be soaked for a long time before the test.The preparation conditions of porous Au-Ag alloy nanoparticle arrays and the relationship between surface morphology and wettability were further discussed.A two-dimensional ordered array of porous Au-Ag-Pt ternary alloy nanoparticles with clean surface and high reproducibility was prepared by template-anneal-dealloying method.The experiment investigated the effects of Ag deposition and Au-Pt ratio on the ordered array to the morphology of porous Au-Ag-Pt alloy nanoparticles.The method has good reproducibility and solves the problem of surfactant on the surface of porous nanoparticles prepared by wet chemistry.In addition,the ordered array of Au-Ag-Pt ternary porous nanoparticles is expected to solve the problems of insufficient active area of Pt based nanomaterials and difficulty in recovery,which provides a new idea and the material basis for the preparation and catalytic application of the ordered array of Pt based ternary porous nanoparticles with a clean surface.