Metal–Single Atom Support Interactions for Enhancing Proton-Exchange Membrane Fuel Cell Cathode Stability: A Review

Proton-exchange membrane fuel cells (PEMFCs) serve as a critical technological avenue for the large-scale advancement of renewable energy and the attainment of the goals of carbon peak and carbon neutrality. However, the sluggish oxygen reduction reaction (ORR) at the cathode and the high dependence upon expensive and scarce platinum group metal (PGM)-based catalysts are the main bottlenecks limiting the large-scale development of PEMFCs. Therefore, the development of non-PGM-based catalysts, especially the highly promising single-atom catalysts (SACs), has emerged as an effective solution to reduce costs. However, the insufficient long-term stability of SACs under PEMFC operating conditions severely hampers their practical application. Metal–support interactions (MSI) are generally considered an effective strategy for enhancing the stability of SACs. Consequently, this review explores the topic of enhancing the stability of SACs in the cathode of PEMFCs by constructing single-atom-supported metal catalysts with MSI. In the discussion, the degradation pathways of SACs are initially outlined, followed by an exploration of MSI principles, synthesis strategies for single-atom-supported metal catalysts based on MSI, and their applications in enhancing the stability of PEMFC cathodes. Finally, an overview is provided regarding the challenges in the future development of single-atom-supported metal catalysts.