Ultra-small Pt on a Ce–Mn binary oxide nanocomposite as a robust oxygen reduction reaction catalyst with enhanced methanol crossover tolerance

Abstract

Benchmarked platinum-based catalysts exhibit promising ORR activity in fuel cell (FC) systems; however, the high cost of Pt hinders their large-scale deployment. Herein, we develop a rational design of an economical and high-performance catalyst comprising ultra-small Pt nanoparticles loaded on a Ce–Mn binary metal oxide nanocomposite. Comprehensive morphological, structural, and surface characterization studies confirm successful synthesis of the targeted architecture. The optimized Pt₄/Ce–Mn–O catalyst containing 4 wt% Pt demonstrates higher ORR activity as a cathode material with enhanced methanol crossover tolerance, outperforming commercial Pt/C (20 wt%). The superior performance of the catalyst is mainly attributed to strong metal–support interactions (SMSI) and chemisorption of abundant O_ads species supplied by oxygen-rich metal oxide surfaces. Moreover, the efficient ionic conductivity through ionomer-to-catalyst channels effectively negates the methanol crossover effect that resulted in high power density and durability in fuel cells, highlighting its favourable potential for sustainable energy technologies.