One‐Pot Synthesis of Carbon‐Supported Pd Nanoparticles with Ni and Carbon Matrix Protection for Durable Alkaline Hydrogen Oxidation Reaction

Protecting nanoparticles with a carbon matrix can enhance the durability of the catalysts in alkaline fuel cells (AFC) and is well-documented. While others have tried complex syntheses to produce small nanoparticle catalysts, in this work, in order to scale-up batches of 15 g or more, carbon-cap (or carbon-coating) protected Vulcan XC72-supported Pd-Ni (1-2) nanoparticles (Pd-Niacc/C) were successfully synthesized via a one-step dry-synthesis process. This catalyst was compared with a commercial Pd-Ni/Vulcan XC72 material (PdNi/C, Premetek) in terms of hydrogen oxidation reaction (HOR) activity and stability. To produce less ordered carbon caps (versus graphite/graphene), a low-temperature heat-treatment (below 500°C) was used, resulting in Pd-Niacc/C of unique electrochemical properties: easily electrochemically activated, this catalyst outperforms PdNi/C for alkaline HOR and proves more durable under highly oxidizing accelerated stress test (AST) conditions. Identical location transmission electron microscopy (ILTEM), X-ray photoelectron spectroscopy (XPS) and rotating disk electrode (RDE) measurements demonstrate how the Ni-rich surface plays an important role in HOR activity for both PdNi/C and PdNiacc/C and that the protective carbon-coating of the latter ensures better durability of performance and better resistance to materials degradation.