Carbon Shell‐Encapsulated Metal Alloy Catalysts with Pt‐Rich Surfaces for Selective Hydrogen Oxidation Reaction

Abstract The performance of polymer electrolyte membrane fuel cells (PEMFCs) is deteriorated by the occurrence of reverse current flow. To suppress the reverse current flow, a hydrogen oxidation reaction (HOR)‐selective catalyst based on the molecular sieve effect should be developed. Here, considering the carbon solubility in transition metals, carbon shell‐encapsulated metal alloy nanoparticles with superior HOR selectivity were fabricated using carbon source in metal precursors. In particular, we introduced carbon solubility as the important parameter that should be considered in the catalyst design. Using Pt and Co with different carbon solubility, as a model catalyst, the effect of the metal composition of the core material on the carbon shell structure was discussed in detail. Due to the formation of high‐density carbon shell and Pt‐rich surface on the alloy nanoparticle, the HOR selectivity was remarkably enhanced. Therefore, this study provides insights into the development of carbon shell‐encapsulated nanoparticles for reaction‐selective catalysis.