Developing practical high-Pt-Loading Pt/C electrocatalysts for proton exchange membrane fuel cells

Proton exchange membrane fuel cells (PEMFCs) are widely recognized as a promising clean energy technology for transportation and distributed power generation due to their high efficiency, low emissions, and rapid response. However, their widespread adoption is still impeded by the sluggish oxygen reduction reaction at the cathode and the high cost of Pt-based electrocatalysts. Although major efforts have been devoted to lowering Pt usage, high‑platinum-loading Pt/C catalysts, defined here as catalysts with a high Pt-to‑carbon ratio, continue to play a central role in practical PEMFCs, particularly in applications where high power density, electrode robustness, and long-term durability are essential. This review provides a critical overview of recent progress in high‑platinum-loading Pt/C catalysts, spanning synthesis methods, structural and interfacial engineering, carbon support modification, durability improvement, and integration into membrane electrode assemblies. Particular attention is paid to the relationships between catalyst structure, Pt utilization, mass transport, and long-term stability under realistic operating conditions. The remaining challenges and future opportunities are discussed to define rational design strategies for next-generation PEMFC cathodes. Overall, this review highlights the continuing importance of high‑platinum-loading Pt/C catalysts in closing the gap between laboratory catalyst development and commercially relevant PEMFC operation.