Low‐Pt NiNC‐Supported PtNi Nanoalloy Oxygen Reduction Reaction Electrocatalysts—In Situ Tracking of the Atomic Alloying Process

We report and analyze a synthetic strategy toward low-Pt platinum-nickel (Pt-Ni) alloy nanoparticle (NP) cathode catalysts for the catalytic electroreduction of molecular oxygen to water. The synthesis involves pyrolysis leaching Ni-organic polymers, subsequent Pt NP deposition, followed by thermal alloying, resulting in single Ni atom site (NiNC)-supported PtNi NPs at low weight loadings only 3–5 wt %. Despite loading, exhibit more favorable Pt-mass activities compared conventional 20–30 % benchmark catalysts. Using situ microscopic techniques, we track unravel key stages formation process directly atomic scale. Surprisingly, find that carbon-encapsulated metallic [email protected] structures, rather than NiNx sites, act as source during formation. Our materials concepts offer pathway further decrease overall content hydrogen fuel cell cathodes.