碳基针孔组合微电极的性能测试与理论验证

Performance of the Combined Electrode with Micro Holes Needling through the Insulating Film of Carbon Rod

在涂敷绝缘漆的碳电极上,用针尖刺穿绝缘膜,形成组合微盘电极.在铁氰化钾与亚铁氰化钾溶液体系测得电极的循环伏安曲线与理论计算曲线十分吻合.阶梯扫描伏安法测得的极限扩散电流,与亚铁氰化钾浓度和扫描速率平方根都成良好的线性关系.在氯化钾支持电解质溶液中,测得Cd(Ⅱ)的循环伏安曲线是不可逆的,Cd(Ⅱ)的还原波峰电位在-0.98V(相对于饱和甘汞电极)附近;800mV·s-1阶梯扫描速率下,在2.55×10-5～1.28×10-4mol·dm-3浓度范围内,Cd(Ⅱ)的浓度与还原波峰电流成良好的线性关系.

A microelectrode is combined with micro holes formed by needling through the insulating film of carbon rod. (see Fig.1). The cyclic voltammogram(see Fig.2) of this electrode determined in solution of K3Fe(CN)6/K4Fe(CN)6 are fully identical with the theoretical curves. The limiting diffusion current determined from step scanning volt ammetry method is in good linear relation with the concentration of K4Fe(CN)6 solution(see Fig.5) and with the square of scanning rate. The cyclic voltammetric curve of Cd2+ in solution with base electrolyte KCl is an irreversible process(see Fig.3). The current of reduce peak (at -0.98 V vs SCE), determined from step scanning voltammetric method at 800 mV·s-1 scanning rate, is in good linear relation with the concentration of Cd2+ at 2.55×10-5 mol·dm-3 to 1.28×10-4 mol·dm-3.