Catalytic Performance And Detection Of Precious Metal Nanoparticles

Surface Enhanced Raman Scattering?SERS?is a technology used to characterize molecular vibration information.It has a wide range of applications in trace detection of toxic and hazardous substances,biomedical detection,and environmental detection.Precious metals are the best materials for preparing SERS substrates,especially nanoparticles of precious metals.They have attracted a lot of attention because of their high SERS enhancement factor and simple preparation.However,the main problem that affects the performance of SERS is that nanoparticles are easily agglomerated.In order to achieve the controllable aggregation of nanoparticles,silver nanoparticles under phytic acid micelles were prepared by the redox method in this paper.Gold nanoparticles under phytic acid micelles were synthesized by the substitution reaction between silver nanoparticles and HAu Cl₄,utilize the properties of phytic acid to improve the enhancement performance of SERS substrate by adding Fe³⁺.All of above samples are characterized by SEM,TEM,Raman spectrometer.It was proved that Fe³⁺can enhance the SERS enhancement performance of phytic acid-terminated gold nanoparticles.Nanozyme is a kind of nano material with simulated protease enzyme activity.At present,the research on the activity of nano-enzyme and micro-detection are generally carried out by oxidizing the chromogenic substrate TMB to produce colored ox TMB.In this paper,gold-polyaniline?Au/PANI?and silver-polyaniline?Ag/PANI?nanocomposites were prepared by a one-step redox polymerization method.The SERS technology was used to study the simulated peroxidase activities of two nanomaterials,and the activities of the two enzymes were compared.From the study of enzyme activity,Ag/PANI has higher peroxidase activity than Au/PANI.In addition,nanocomposites not only have mimic peroxidase activity,but also glucose oxidase activity,and the highest enzyme activity was at p H=4.0.Under the optimal conditions,the nanocomposite can be used as a tandem enzyme to directly provide H₂O₂ by directly oxidizing glucose,and then reacting to oxidize TMB to achieve indirect detection of glucose with a detection limit of 10^-10 M.