One-pot synthesis of carbon-supported AuCo and AuNi nanoalloys for the oxygen reduction reaction in alkaline media

Carbon-supported bimetallic AuCo and AuNi electrocatalysts were prepared from one-pot wet-chemistry techniques (ethylene glycol-stabilization and aqueous-solution stirring) and evaluated for the oxygen reduction reaction (ORR) in alkaline media. All the materials consist of near-spherical nanoparticles that show varying sizes and extent of agglomeration. While the ethylene-glycol method produced less agglomerated particles, the stirring method produced smaller ones. X-Ray photoelectron (XPS) analyses demonstrated the change in the binding energies of Au 4f 515 and Au 4f 712 versus the expected values for pure gold, pointing at the formation of alloyed nanoparticles. The combination of such electronic effects and morphology led the AuNi/C-EG nanoalloy to a good compromise between materials cost (versus Au/C) and ORR activity: the onset potential and half-wave potential for the oxygen reduction reaction are 0.833 and 0.600 V vs. RHE, respectively, corresponding to a specific activity 10% greater than that for Au/C at 0.85 V vs. RHE. The carbon-supported AuNi nanoalloy possesses undoubtable potential to be used as an electrocatalyst for the electroreduction of oxygen in alkaline environments.

Automated summary

Carbon-supported bimetallic AuCo and AuNi electrocatalysts were prepared using one-pot wet-chemistry techniques and evaluated for the oxygen reduction reaction in alkaline media. The AuNi/C-EG nanoalloy showed a good compromise between materials cost and ORR activity, making it a promising electrocatalyst for the electroreduction of oxygen in alkaline environments.