Engineering the Electronic Interaction Between Single Au Atoms and CoN Through Nitrogen-Coordination Bonding as an Efficient Bifunctional Electrocatalyst for Rechargeable Zn-Air Batteries

Single-atom catalysts hold significance in the field of electrocatalysis. In this study, cobalt nitride (CoN), known for its semiconductor characteristics, is selected as the substrate, on which single gold (Au) atoms are loaded, to synthesize the catalyst Au SAC CoN@NF with Au single atoms anchored on CoN catalysts and grown on nickel foam. The introduction of single Au atoms results in an exceptional double-layer capacitance (1425.7 mF cm-2), which offers immense possibilities for the applications of zinc-air batteries based on Au SAC CoN@NF. The zinc-air batteries demonstrated remarkable performance metrics, including a power density of 161.94 mW cm-2, a specific capacity of 813.80 mAh g-1, and a cycling stability of more than 260 h at 10 mA cm-2. In addition, these batteries show an outstanding round-trip efficiency of 65.1%. Density functional theory calculations reveal that Au SAC CoN@NF can optimize the adsorption energies of intermediates for oxygen evolution reaction and promote single Au atoms in transporting electrons to the OH- species at an Au-N active site for oxygen reduction reaction. The proposed electronic metal-support interaction strategy offers fresh insights for designing single-atom catalysts to enhance electrocatalysis efficiency, thereby expanding the practical application prospects of zinc-air batteries. Au SAC CoN@NF improves the bifunctional intrinsic catalytic activity by designing electronic metal-support interactions between single gold (Au) atoms and CoN through nitrogen coordination bonds. The strong hybridization of Co (dxz, dz2) and OO* electronic orbitals are assisted by the synergistic effect of electronic and geometrical coordination structures, resulting in rechargeable zinc-air batteries with voltaic efficiency as high as 65.1%. image