摘要
电活性质点Fe^(2+)可穿透六氰亚铁钒薄膜在玻璃碳基体电极表面于较负电位处直接氧化,也可经VHF膜中氧化还原点位的媒介在较正电位处于膜-溶液界面及膜内部发生催化氧化.两个过程分别在用VHF修饰过的旋转GC电极上的伏安曲线中产生,可明确分辨的第一波和第二波.第一波的极限电流受Fe^(2+)离子在溶液中和膜中的扩散速率控制.VHF薄膜对Fe^(2+)离子的透过能力,kD_m/d,为10^(-3)-10^(-2)cm·s^(-1)数量级,随膜厚度增大而减小,不随溶液中Fe^(2+)离子浓度改变.
It is demonstrated that the electroactive species Fe^(2+) ion can transport easily
through the thin films of vanadium hexacyanoferrate (VHF) to the underlaying
glassy carbon (GC)electrode surface to be oxidized directly at less positive potential and
that it can also be oxidized at the film at more positive potential through the media-
tion of redox sites in the film. These two processes yield sequentially clearly distinguished
first and second wave in stationary current-potential curves resulting from a rotating
disk electrode. The plateau current of the first wave is limited by the diffusion rate
of Fe^(2+) ion both in the solution and in the film. The permeability parameter, kD_m/d, of
the VHF film to Fe^(2+) ion is measured to be the order of magnitude of 10^(-3)-10^(-2)cm.
s^(-1), which decreases linearly with the increase of film thickness and remains constant
when the bulk concentration of Fe^(2+) ion in the solution varies.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
1989年第3期233-239,共7页
Acta Chimica Sinica
