High entropy alloy implanted nitrogen-doped carbon catalysts synthesized via calcined polyurea for efficient CO ₂ reduction reaction

Abstract

High-entropy alloy-implanted nitrogen-doped carbon (HEA/NC) catalysts are promising for CO ₂ electroreduction owing to their tunable active sites and robust structures. We report a one-pot polyurea-derived route to synthesize FeCoNiCu/NC- and FeCoNiCuAg/NC-800 catalysts via calcination at 800 °C followed by acid leaching, yielding porous graphitized carbon frameworks with atomically dispersed M–Nx moieties. Comprehensive characterization confirmed the presence of face-centered cubic phases and uniform metal dispersion. In 0.5 M KHCO ₃ , both catalysts achieved CO Faradaic efficiencies above 85 % at −0.95 V versus RHE, with Ag incorporation further enhancing stability (a sustained current of 23 mA cm ⁻² ) and durability. In-situ Raman revealed *COOH as the dominant intermediate, highlighting the synergistic role of multi-metallic sites, notably Ag, in modulating CO ₂ RR pathways. This work presents a simple, scalable synthesis strategy that provides mechanistic insights into the design of durable, high-performance HEA-based CO ₂ RR catalysts.