Electrochemical Recovery of Pt/C Catalyst from Aged MEA—Alkaline Electroleaching in the Presence of Ammonia

Abstract

The energy transition requires the development of efficient and decarbonized energy storage and conversion systems. In this context, dihydrogen (H2) is a promising energy carrier. Ideally, it should be produced through water electrolysis using intermittent renewable energy sources (solar, wind, etc.) to be further utilized in a fuel cell to generate electricity. To date, proton-exchange membrane fuel cells are the most efficient and mature H2 conversion technology. However, a major drawback relies on the use of noble metals, such as platinum (Pt), as electrocatalysts for the electrochemical reactions involved in this device. Deploying these technologies requires the development of an efficient recycling pathway to reduce pressure on these natural resources. This study aims to identify an optimized way to electrochemically recover Pt salts from a Pt/C catalyst in alkaline conditions. A three-step electrochemical protocol was applied in the presence of ammonia as a complexing agent with the objective to favor Pt dissolution while preventing both Pt particles detachment and Pt redeposition. As a result, this process demonstrated a high yield (i.e., ≥90%) of Pt leaching on the model Pt/C catalyst. Finally, the selected protocol was transferred to a membrane electrode assembly (MEA) aged in realistic conditions as a proof of concept.