Bifunctional Arrays of NiRu Single-Atom Alloy Nanoparticles Confined in a Porous Carbon Nanosheet for Sustained Anion-Exchange Membrane Water Electrolysis

Single-atom alloys (SAAs) are promising catalysts due to their unique electronic/geometric structures and high atomic efficiency, yet precise control of guest metal atoms and host nanoparticle dispersion remains challenging. This study develops a facile ion exchange-pyrolysis strategy to synthesize ultrafine NiRu SAA nanoparticles confined in porous carbon (NiRu/C) nanosheet arrays. Advanced characterization confirms isolated Ru atoms anchored on Ni nanoparticles with electron transfer from Ni to Ru, achieving uniform dispersion in ultrathin carbon. Theoretical analysis indicates that Ru single atoms optimize reactant adsorption and reduce energy barriers for rate-determining steps, enhancing both hydrogen and oxygen evolution. As bifunctional electrodes in anion-exchange membrane water electrolyzers, NiRu/C demonstrates a low voltage of 1.75 V at 1 A cm^-2 at 60 °C with 350 h stability, showcasing SAAs' potential for efficient green hydrogen production.