Preparation And Investigation On Their Electrochemical Behavior Of Nano-composite Based Electrodes With Incorporated Redox Enzymes

Enzyme based biofuel cells with high energy density and high output power are one of the current research hotspots.There are mainly two factors that restrict the electrochemical performance of enzyme based biofuel cells: Effective electron transfer between the enzyme and the electrode;The structure of the coordination active center of the enzyme and the influence of the catalytic mechanism remaining to be solved.In this paper,three kinds of nanocomposites were prepared by mechanical blending or chemical coupling of nanomaterials and molecules containing hydrophobic aromatic rings or aromatic heterocycles,And take it as enzyme carrier,Enzymes are immobilized by chemical coupling,physical adsorption or coordination complexing to prepare immobilized enzyme nanocomposites.Enzyme-Based Electrode was prepared by drop coating or chemical coupling,and its structure and morphology were characterized.The electrochemical properties of Enzyme-Based Electrode were characterized by electrochemical impedance spectrometry(EIS)and cyclic voltammetry(CV).The main contents and conclusions of this paper are summarized as follows:1 3,4,9,10-Perylene Tetracarboxylic acid coupling with functionalized multi-walled carbon nanotubes act as enzyme carrier,chemical coupling with laccase,which is anchored on the surface of nano composites,the performance of oxygen reduction by laccase based electrode has been studied,The experimental results show that the reaction on the surface of the electrode is the type of thin film control.2 Dependences of structural parameters and operational conditions on enzymatic catalysis of substrates(glucose and oxygen)for basal electrodes over-coated by composite consisting of nano-gold particle and polymer,were investigated systematically by the means of electrochemistry and spectrometry.Rate constants of steps involved in the whole catalytic cycle were estimated under the same dimension and were compared to confirm the limiting factor in the whole catalytic cycle.Results from experiments indicated that nano-gold particle surface anchored with aromatic ring as conductive support played the important role in achieving direct electron transfer between cofactors in redox protein molecules and electrical wired matrix.Complexations between components of nano-composite and redox sites within incorporated enzyme molecules acted as the paradoxical role in promoting the catalytic efficiency in the long term.Electrochemical conversion of substrates into product was identified to be the rate limiting step in the whole catalytic cycle for enzyme based electrodes.3 Enzymatic electrodes over-coated by thin film of nano-composite made up of polymer and functionalized nano-gold particle was prepared.Glucose/O2 membrane-free enzymatic fuel cell based on nano-composite based electrodes with incorporated glucose oxidase and laccase was assembled.This enzymatic fuel cell exhibited high energy out-put density even when applied in human serum.Catalytic cycle involved in enzymatic fuel cell was limited by oxidation of glucose occurred on bioanode resulting from impact of sophisticated interaction between active site in glucose oxidase and nano-gold particle on configuration of redox center of enzyme molecule which crippled catalytic efficiency of redox protein.4 The 2-hydroxy-4-amino-azobenzene(AZO-1)was functional with grapheme oxide(GO)through the covalent bond to obtain functionalized graphene oxide with azobenzene derivatives,which act as the enzyme carrier,chemical coupling with bilirubin oxidase,we studied the direct electron transfer and catalytic oxygen reduction performance of bilirubin oxidase based electrode Bilirubin oxidase has better catalytic oxygen reduction performance.the reaction process of the enzyme-based electrode is the type of diffusion control.