Method of evaluation of electron transfer kinetics of a surface-confined redox system by means of Fourier transformed square wave voltammetry.
A new form of Fourier transformed square wave voltammetry (FT-SWV) is proposed to simplify and accelerate the electron transfer kinetics evaluation procedures for surface-confined redox systems. Even harmonic frequencies, which are derived from the nonlinear Faradaic response, will arise in the power spectrum after Fourier transformation of the current response of FT-SWV. The profile of the even harmonic power spectra is bell-shaped and shows a maximum at a certain frequency. The electrode kinetics-dependent maximum and the corresponding frequency are equivalent to the so-called "quasi-reversible maximum" and "critical frequency" (fmax) in traditional SWV, respectively. The critical frequency can be regarded as a frequency that is synchronized to the electron transfer rate constant (k(0)). As a result, it can serve as a probe of k(0) by means of a very simple equation, k(0) = kmax fmax. Compared with traditional cyclic voltammetry, square wave voltammetry, alternating current voltammetry, and several other voltammetric techniques, this method exhibits great advantages for its simplicity, rapidity, and sensitivity.
Huang
Xinjian
X
College of Chemical Science and Engineering, South China University of Technology, Guangzhou 510641, China.
Wang
Lishi
L
Liao
Shijun
S