Hybrid system based on fast Fourier transform electrochemical impedance spectroscopy combined with scanning electrochemical microscopy

Abstract

Fast Fourier transform electrochemical impedance spectroscopy (FFT-EIS) is a technique that simultaneously applies 30–50 frequencies and simultaneously all data of EIS spectra at these frequencies are registered. Therefore EIS spectra can be acquired many times faster compared to experiments performed by conventional EIS equipment. Scanning electrochemical microscopy (SECM) allows localized electrochemical measurements to be performed by ultramicroelectrode (UME). In this research a hybrid system based on combined SECM and FFTEIS techniques (FFT-EIS/SECM) was developed and it was applied to register impedance spectra at different distances from surfaces of interest. The applicability of the FFT-EIS/SECM-based system for the investigation of electrochemical processes on conducting and non-conducting surfaces was demonstrated. The results show negative- and positive-feedback behavior, which are specific for amperometric measurements by SECM, when electrochemical signals are registered by UME, while approaching insulating and conducting surfaces, respectively.