An active learning laboratory module is designed for two electroanalytical techniques of the Instrumental Analysis Laboratory at Eastern New Mexico University. In the first week, students polish/clean a gold disk electrode, and run cyclic voltammetry (CV) on it in an electrolyte containing a redox couple. Through data analysis, they determine the number of electrons transferred in the half reaction and the dependence of the peak currents on the potential scan rates, analyte concentrations, and supporting electrolytes. In the second week, they run electrochemical impedance spectroscopy (EIS) on a bare gold electrode in an electrolyte containing both redox couples. Through data simulation, they obtain an equivalent circuit to interpret the electrochemical system. In the third week, they form self-assembled monolayers of 1-mercaptodecane (C10) and 1-mercaptooctadecane (C18) on bare gold electrodes with comparable geometric areas and surface roughness factors. Based on chemical literature, they predict the electron transfer behaviors of C10 and C18-monolayer-modifed gold electrodes. After running CV measurements, they overlay three cyclic voltammograms together. In the fourth week, they run EIS on C10- and C18-monolayer-modified gold electrodes. Using chemical literature, they predict the Nyquist plots of C10- and C18-moloalyer-modified gold electrodes. After running EIS measurements, they simulate the Nyquist plots to obtain the equivalent circuits and important parameters of three electrochemical systems (e.g., the charge transfer resistance). Finally, they discuss in groups the suppression of electron transfer of the monolayer-modified gold electrodes compared to that of the bare gold electrode, and write their own comprehensive lab reports using the established grading rubrics.<br/>This module benefits the students in small class sizes. It increases significantly the post-laboratory student-instructor interactions, and provides an excellent opportunity for the students to apply their learning and to improve their skills in experimental design, observation or manipulations of materials and equipment.

Electrode modification through self-assembly and electron transfer characterizations by cyclic voltammetry and electrochemical impedance spectroscopy

253rd National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.