Thermal and chemical activation methods applied to DFAFC anodes prepared by magnetron sputtering

Anodes consisting of Pd and bimetallic PdCu catalysts deposited directly on a carbon cloth by magnetron sputtering have been tested in a direct formic acid fuel cell. Current-voltage measurements showed that a bimetallic Pd-based catalyst temperature-treated to 300 degrees C exhibits the highest catalytic activity. Chemical and structural information from the surface of the catalysts was revealed by X-ray photoelectron spectroscopy (XPS) and by scanning electron microscopy (SEM). Increasing the temperature of the anode together with hydrogen peroxide (H2O2) treatment of the catalyst surface was proposed as an additional treatment method. In this method, the highest catalytic activity was achieved (P = 56 mW mg(-1)) for a monometallic Pd catalyst. The enhanced catalytic efficiency after these methods had been applied was attributed to the decrease in the content of metal oxide forms, carbon-oxygen groups, and PdCx surface contamination, where the PdCx surface content played a major role. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.