Efficient ORR Facilitated by Co Single Atoms Bridged with Nitrides

Abstract Single‐atom catalysts (SACs) with an M─N ₄ configuration have great potential for oxygen electrocatalysis but face challenges in zinc–air batteries (ZABs) due to limited activity and durability. This study reports a composite catalyst, synergistically integrating carbon quantum dots (CQDs) regulates Co Single‐Atoms coordinates cobalt nitride complex (Co SAs/Co ₂ N), prepared via stirring and calcination process. Experimental and density functional theory (DFT) analyses show that Co ₂ N acts as an electron reservoir, donating electrons to Co SAs through a Co─Co bond bridge during the oxygen reduction reaction (ORR). This mechanism suppresses the migration and thermal vibration of Co SAs and optimizes the coordination environment. As a result, Co SAs/Co ₂ N achieves a half‐wave potential of 0.86 V, close to 20% Pt/C. The synergistic coupling of both elements enhances the oxygen adsorption capacity and significantly reduces the kinetic barrier for the movement of Co's d‐band center and O's p‐band center in directions favorable to the ORR process. In ZABs, the catalyst delivers excellent performance with a specific capacity of 800.85 mAh g _Zn ⁻¹ , energy density of 993.21 mWh g _Zn ⁻¹ , high power density of 138.9 mW cm ⁻² , and long‐term durability (1000 h). This work provides a new approach to optimizing SACs and ZAB performance through nitride composites.