A first-principle study of an alloy-supported single-atom catalyst for oxygen reduction reactions

Abstract

The rational design of single atom catalysts with high activity is essential to improve the slow kinetics of the oxygen reduction reaction in metal-air batteries and proton exchange membrane fuel cells. Here, using the first-principles methods based on density functional theory (DFT), the oxygen reduction reactions of single-atom catalysts Co-N-C and Fe-N-C supported on Co₃Fe alloys were further suggested as efficient ORR catalysts. The results indicate that the positions of the non-metallic atoms in the nitrogen-doped carbon are well adapted to the surface layer of the alloy. The overpotentials of the alloy-loaded catalysts are reduced from 0.63 V for Co-N-C and 0.81 V for Fe-N-C to 0.40 V and 0.31 V, respectively, compared with the 2D single atom catalysts. The origin of the activity stems from suitable coordination environments for cobalt and iron, crucially affecting the rate-determining step. This study identifies a new specific link between the alloy coordination environment and catalytic activity, with implications for catalyst design.