A Simple Electrochemical Approach Based on Inexpensive Wall-Jet Screen-Printed Ring Disk Electrode to Evaluate Oxygen Reduction Catalysts

A simple electrochemical approach to evaluate oxygen reduction catalysts using an inexpensive screen-printed ring disk carbon electrode system, consisting of a ring electrode deposited with MnO2 and a disk electrode modified with the catalysts for study, is developed in this study. The as-prepared MnO2 is selective and sensitive for H2O2 oxidation in the presence of O-2 and is crucial to the proposed approach. By coupling with a wall-jet electrochemical cell, the product generated from the reduction reaction at the disk electrode can effectively be monitored at the MnO2- deposited ring electrode. Model catalysts of nano-Au and nano-Pd representing 2e(-) reduction of O-2 to H2O2 and 4e(-) reduction to H2O, respectively, were evaluated as electrode materials in oxygen reduction reaction to demonstrate the applicability of the proposed method.