Fe, Co and Ni Trimetallic Single-Atom Doped Porous Carbon Boosting Oxygen Reduction Reaction and Oxygen Evolution Reaction

Abstract

Trimetallic catalysts have potential for functional complementarity and synergy, making them promising for the combined reactions with multi-intermediates. However, dispersing all three metal species to the single-atom distribution remains a challenge. In this work, a metal encapsulation-interlayer stacking strategy was 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 catalyst demonstrated excellent bifunctional catalytic performance in basic solutions, achieving a half-wave potential as high as 0.878 V (vs. RHE) and low overpotential of 285 mV at a current density of 10 mA cm-2. Additionally, it showed impressive ORR performance in acidic solutions, attaining a half-wave potential of 0.814 V (vs RHE). Density functional theory (DFT) calculations have revealed that the elevated d-band center contributes to increased adsorption of reactive intermediates at the Fe-N4 and Co-N4 sites, thereby improving the ORR and OER activities. This study provides a straightforward and effective approach for synthesizing efficient and robust trimetallic single atom M-N-C ORR/OER catalysts of Zn-air batteries.

Keywords: encapsulation-interlayer stacking, trimetallic single-atom, synergistic interaction, bifunctional catalytic performance, Zn-air battery