Design,Preparation And Catalytic Application Of Bimetallic Nanozymes

Nanozyme is a new type of substance that can replace the biological enzyme to detect the substrate.It is generally composed of metal nanoparticles,alloy nanoparticles,metal-organic framework(MOF),or composite materials and so on.Compared with the instability of biological enzymes,the nanozyme has the advantages of stability,simple preparation process,low cost,and promising application prospects.Several nanozymes were prepared in this paper and their properties were investigated.The specific research contents are as follows:Preparation and properties of PtPd mesoporous nanozymes.In this paper,PtPd mesoporous nanozyme was prepared using hydrothermal method while F127 as a template,ascorbic acid as a reducing agent,chloroplatinic acid,disodium tetrachloropalladate and potassium tetrachloroplatinate as raw materials.Scanning electron micrograph(SEM),transmission electron microscopy(TEM),energy dispersive spectroscopy(EDS)and X-ray diffraction(XRD)were performed.The p H,temperature,substrate concentration and nanozyme concentration of the reaction were optimized.Dynamics kinetics,detection range and thermal stability were studied.The experimental results show that the PtPd mesoporous nanozyme has peroxidase properties and can be used to catalyze hydrogen peroxide and discolor 3,3',5,5'-tetramethylbenzidine(TMB).When hydrogen peroxide is used as a substrate,the Michaelis constant is 2.26 m M and for TMB is 0.104 m M.The detection range of the obtained hydrogen peroxide solution is 0.005-2000?mol·L^-1,and the glucose is 0-4000?mol·L^-1.Thermal stability experiments show that the activity of PtPd mesoporous nanozymes remains almost unchanged at high temperatures.Preparation and performance of molecularly imprinted PtPd mesoporous nanozymes.In order to improve the catalytic activity and substrate specificity of nanozymes,TMB molecules were used as templates,acrylamide,N-isoacrylamide and N,N'-methylene acrylamide were used as gel raw materials in PtPd mesoporous nanometers.An acrylamide gel film was formed on the surface of the enzyme,and the TMB molecule was blotted,and the TMB molecule was washed away to obtain a pocket compatible with the TMB molecule.The SEM,TEM,EDS and TEM mapping were performed.The catalytic properties of PtPd mesoporous nanozyme,PtPd mesoporous gel nanozyme and molecularly imprinted PtPd mesoporous nanozyme were compared.The results showed that the prepared molecularly imprinted PtPd mesoporous nanozyme activity is nearly double that of the original PtPd mesoporous nanozyme and PtPd mesoporous gel nanozyme.Besides,the specificity and the detection range are also greatly improved.Preparation and properties of the integrated nanozymes(GOx@PtCu).In order to simplify the reaction step of detecting glucose,the glucose oxidase is loaded onto the PtPd mesoporous nanozyme,so that the glucose molecule can complete the cascade reaction on the integrated nanozymes,and can detect the concentration of the glucose solution at one time.In order to reduce the production cost,Pd in the original PtPd mesoporous nanozyme was replaced with Cu,and PtCu mesoporous nanozyme was prepared.The effects of time,temperature,enzyme concentration and carrier concentration on the preparation of GOx@PtCu were investigated.The catalytic performance of GOx@PtCu was analyzed.The experimental results show that the glucose solution concentration range of GOx@PtCu is400-800?mol·L^-1.