Origins of Nanoalloy Catalysts Degradation during Membrane Electrode Assembly Fabrication

Abstract

Despite extensive efforts to reduce the costs of high-performance electrochemical devices, incorporating catalyst materials frequently falls short of achieving performance targets. Platinum alloys, known for their high oxygen reduction activity, exemplify this challenge due to integration difficulties. Here, we introduce an in situ X-ray diffraction approach to investigate structural changes in PtCo and PtNi catalysts during ink preparation. Contrary to previous assumptions that acidity is the main factor driving catalyst dissolution, our findings demonstrate that temperature plays a more critical role. Additionally, we observe rapid structural degradation during the hot-pressing of catalyst-coated membranes (CCMs), a critical yet often unavoidable processing step. These results indicate that significant catalyst deactivation can occur before operation, emphasizing the need for optimized fabrication processes. This study highlights the importance of refining ink formulation and processing protocols to fully leverage advanced materials in CCM-based energy conversion systems.