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

• Published in: ChemElectroChem Vol. 9; no. 17
• Main Authors: Ko, Keonwoo, Min, Jiho, Kim, Yunjin, Hong, Min Woo, Jeffery, A. Anto, Chougule, Sourabh S., Bok Yi, Kwang, Jung, Namgee
• Format: Journal Article
• Language: English
• Published: Weinheim John Wiley & Sons, Inc 13.09.2022
• Subjects: carbon shell; carbon solubility; Catalysis; Catalysts; Electrolytic cells; Encapsulation; molecular sieve effect; Molecular sieves; Nanoalloys; Nanoparticles; Oxidation; Proton exchange membrane fuel cells; reaction selectivity; reverse current flow; Selectivity; Shells (structural forms); Solubility; Transition metals
• ISSN: 2196-0216; 2196-0216
• DOI: 10.1002/celc.202200342

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. Rational synthesis: Carbon shell‐encapsulated PtCo alloy nanoparticles were designed by considering the carbon solubility in transition metals to suppress the reverse current flow, and systematically studying the effect of metal composition on the carbon shell structure. The high‐density carbon molecular sieve layer and the Pt‐rich alloy surface remarkably enhanced HOR selectivity.