Fe, Co and Ni trimetallic single-atom doped porous carbon boosting oxygen reduction reaction and oxygen evolution reaction

Trimetallic catalysts exhibit potential for functional complementarity and synergistic interactions, rendering them promising for catalyzing reactions involving multi-intermediates. However, achieving a uniform dispersion of all three metal species at the single-atom level continues to pose a significant challenge. In this work, a metal encapsulation-interlayer stacking strategy is developed to prepare FeCoNi@NC triple single-atom catalysts. Benefiting from the synergistic interplay among the M-NX (M = Fe, Co, and Ni) active sites, the FeCoNi@NC TACs demonstrate superior bifunctional catalytic efficacy in alkaline solutions, with a half-wave potential reaching 0.878 V (vs. RHE) and a minimal overpotential of 285 mV at a current density of 10 mA cm−2. Furthermore, it exhibits remarkable ORR performance in acidic environments, achieving a half-wave potential of 0.814 V (vs. RHE). DFT calculations elucidate that an elevated d-band center enhances the adsorption of reactive intermediates at the Fe-N4 and Co-N4 sites, consequently augmenting ORR and OER activities. This study delineates a direct and effective methodology for the synthesis of high-performance and durable trimetallic single atom MNC ORR/OER catalysts for Zn-air batteries.