What it is
The authors introduce high-entropy metallenes, two-dimensional high-entropy alloys made by combining several single-atom metals in atomically thin layers, to counter the fact that conventional nanoparticle catalysts bury most active atoms in the particle core. By exposing many active centers across the metallene, the multimetal surface jointly lowers the energy barrier of the rate-determining step for electrocatalytic nitrate reduction to ammonia. A proof-of-concept PdCuNiCoZn metallene works across wide pH ranges and, in strongly alkaline electrolyte, reaches a maximum ammonia yield rate of 447 mg h-1 mg-1 at a Faradaic efficiency of 99.0%.
Why it matters
High-entropy alloys are prized catalysts, but their conventional nanoparticle shape wastes most active atoms by trapping them in the particle core. Recasting them as atomically thin metallenes exposes far more of those atoms, and the resulting nitrate-reduction performance, a high ammonia yield rate at near-complete Faradaic efficiency in alkaline conditions, shows the approach can convert nitrate to ammonia efficiently.
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Filed underAmmonia Synthesis and Nitrogen Reduction, Nanomaterials for catalytic reactions, Advanced Photocatalysis Techniques