High-Throughput Activity Screening of Oxygen Reduction and Oxygen Evolution Catalysts

Abstract

High-throughput techniques are being actively studied to expedite the evaluation of the electrocatalytic activity of newly developed materials. These techniques include the use of optical sensing or electrochemical array cells in stagnant or hydrodynamic aqueous electrolytes [1-2]. A new high-throughput electrochemical cell has been developed utilizing multiple glassy carbon working electrodes with dimensions comparable to those of a conventional ring-disk electrode (RDE) that are inserted into a channel flow cell (Figure 1) comprised of two PEEK blocks separated by a gasket that defines the electrolyte channel depth. This cell enables evaluation of the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) activity as a function of the potential of multiple catalyst samples simultaneously that are deposited on the glassy carbon electrodes using standard methods used for RDE electrodes (e.g., using a hand-held micropipette). As shown in Figure 1, a common reference electrode is located in the lower cell block across an electrolyte channel from the working electrodes and a common counter electrode is located in the electrolyte outlet. Electrolyte flow has been simulated to ensure that the electrolyte is evenly distributed throughout the shallow flow channel with uniform laminar electrolyte flow and identical flow rate for all working electrodes. The new cell is coupled with a Bio-logic multichannel Potentiostat (VSP) that allows the use of multiple working electrodes simultaneously with a common counter electrode and common reference electrode. The catalyst activity and stability results obtained with the new cell have been verified by comparison with RDE measurements for the same catalysts. Acknowledgments This work was supported by the U.S. Department of Energy, Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office under the auspices of the Electrocatalysis Consortium (ElectroCat). Argonne National Laboratory is managed for the U.S Department of Energy by the University of Chicago Argonne, LLC, also under contract DE-AC-02-06CH11357.