The Fabrication And Colorimetric Sensing Application Of Transition Metal Nanozymes

Nanozyme is a new type of artificial mimic enzyme.It not only has unique physical and chemical properties of nanomaterials,but also has the catalytic activity of natural enzymes.In recent years,with the rapid development of nanomaterials,nanozymes researches have been growing at an exponential rate.They have attracted enormous interests due to their good stability,low cost and easy preparation,and thus been used in biomedical,environmental and food fields.In this paper,two transition metal materials nanozymes were synthesized successfully and then used to fabricate colorimetric sensors for the detection of hydrogen peroxide quantitatively.The main contents are as follows:1.Firstly,the nickel-cobalt Prussian blue analog(Ni-Co PBA)was synthesized and then characterized by scanning electron microscopy.The result showed that the size of NiS was uniform.Then.NiS was synthesized by hydrothermal method,in which Ni-Co PBA was used as the nickel source,thioacetamide was used as the sulfur source.Subsequently,the materials were characterized by X-ray energy spectroscopy,transmission electron microscopy and scanning electron microscopy.The result showed that the NiS has a hollow porous structure.Next,the performance of NiS was studied.It can be seen that NiS can catalyze the oxidation of the colorless 3,3',5,5'-tetramethylbenzidine to blue ox-TMB under the presence of hydrogen peroxide(H2O2).The result illustrated that NiS nanoparticles have very good catalytic properties.Experimental conditions were optimized.The kinetic analysis results showed that the catalytic kinetics curve conforms to the Michaelis-Menten equation and the catalytic mechanism follows the ping-pong mechanism.The affinity of NiS to TMB and H2O2 was stronger than that of horseradish peroxidase.Based on this property,a colorimetric sensor was designed to quantitatively detect hydrogen peroxide.The detection range and detection limit were 4-40 and 1.72?M,respectively.2.The sodium lignin sulfonate-modified iron oxide was synthesized by hydrothermal method,and then used to prepare Fe3O4-Cu2+nanocomposites through adsorption method.The morphology and composition of materials were characterized by X-ray energy spectroscopy,scanning electron microscopy,transmission electron microscopy and so on.The catalytic performance was studied,and the result showed that Fe3O4-Cu2+nanocomposites possess excellent catalytic performance.Furthermore,the catalytic kinetics curve conforms to the Michaelis-Menten equation and the catalytic mechanism follows the ping-pong mechanism.Based on this property,a colorimetric sensor was constructed to quantitatively detect hydrogen peroxide.The detection range and detection limit were 2.5-100 and 0.212?M.Moreover,the specificity and selectivity of this method are very good.