甲基纤维素修饰电极对H_2O_2电催化还原的研究

Direct Electrochemistry and ElectrocatalysisH_2O_2of Catalase Entrapped in Methyl CelluloseHydrogel Films

用甲基纤维素(MC)将过氧化氢酶(Cat)固载于热裂解石墨电极表面,制备了Cat-MC膜修饰电极.甲基纤维素膜中的过氧化氢酶与电极直接传递电子.在pH6.0的磷酸盐缓冲溶液中可得到一对可逆的过氧化氢酶辅基血红素Fe(III)/Fe(II)电对氧化还原峰,式电势为-0.331V(vsSCE).其式电势随溶液的pH值增加而负移且成线性关系,直线斜率为-38.0mV/pH,说明过氧化氢酶的电子传递过程伴随有质子的转移.并研究了过氧化氢酶修饰电极对H2O2的电催化性能.在H2O2一定浓度范围(15.6～110.1μmol/L)内,催化电流与H2O2浓度成线性关系.

Catalase was immobilized on edge-plane pyrolytic graphite (EPG) electrodes by Methyl Cellulosehydrogel. The protein entrapped in the Methyl Cellulosefilm undergoes fast direct electron-transfer reactions with the formal potential (Eo') of -0.331 V(vsSCE), corresponding to Fe^(III)+ e^(-)→ Fe^(II), The Eo's are linearly dependent on solution pH with the slope value of -38.0 mV/pH, indicating that the electron transfer was proton-coupled. The mechanisms for catalytic reduction of hydrogen peroxide by Catalase entrapped in Methyl Cellulosehydrogel were also explored. The cathodic peak current increase linearly with the concentration of H_(2)O_2in the range of 15.6 ～ 110.1 μmol/L.