氢氧化镍薄膜修饰玻碳电极的制备及其对L-赖氨酸氧化的电催化活性

采用恒电位沉积方法将氢氧化镍沉积到玻碳电极表面,得到稳定性高、催化活性好的氢氧化镍薄膜修饰玻碳电极;分析了影响薄膜形成过程的关键因素,确定了最佳薄膜制备方案;与此同时,将薄膜修饰玻碳电极用于生物样品L-赖氨酸的氧化测定,并探讨了其催化作用机理.结果表明,所制备的氢氧化镍薄膜修饰玻碳电极表面发生电化学反应Ni(OH)2→NiOOH],从而促进电极表面的电子转移,实现对L-赖氨酸的电催化作用.当L-赖氨酸的浓度在1.0×10-4～4.0×10-7 mol/L范围内时,相应氧化峰电流与浓度呈线性关系,检出限达4.0×10-7 mol/L;据此可方便地制备稳定性好且灵敏度高的电流型传感器.

Preparation of a glassy carbon electrode modified by nickel hydroxide film and its electrocatalytic activity towards oxidation of L-lysine

Nickel hydroxide was deposited on the surface of glassy carbon electrode by electro- deposition under potentiostatic conditions to afford a nickel hydroxide film-modified glassy car- bon electrode possessing good stability and electrocatalytic activity. The factors influencing the formation of the nickel hydroxide film were analyzed, and the optimal condition for preparing desired nickel hydroxide film was established. In the meantime, as-prepared glassy carbon elec- trode modified by nickel hydroxide film was adopted to determine the oxidation of L-lysine, and the catalytic mechanism of the modified electrode was discussed. Results indicate that as-pre- pared modified glassy carbon electrode undergoes surface electrochemical reaction Ni（OH）2→NiOOH] thereby accelerating surface electron transfer and realizing electrocatalysis towards the oxidation of L-lysine. When the concentration of L-lysine is in the range of 1.0× 10^-4 --4.0 × 10^-7 mol/L, it is linearly proportional to relevant oxidation peak current, and corresponding detect limit is as low as 4.0×10^-7 mol/L. This makes it feasible to fabricate current-type sen- sors with good stability and sensitivity via a facile route.