Atomically Dispersed Co<sub>2</sub>–N<sub>6</sub> and Fe–N<sub>4</sub> Costructures Boost Oxygen Reduction Reaction in Both Alkaline and Acidic Media
Zhe Wang, Xiaoyan Jin, Chao Zhu, Yipu Liu, Hua Tan, Ruiqi Ku, Yongqi Zhang, Liujiang Zhou, Zheng Liu, Seong‐Ju Hwang, Hong Jin Fan
Abstract
Abstract Polynary transition‐metal atom catalysts are promising to supersede platinum (Pt)‐based catalysts for oxygen reduction reaction (ORR). Regulating the local configuration of atomic catalysts is the key to catalyst performance enhancement. Different from the previously reported single‐atom or dual‐atom configurations, a new type of ternary‐atom catalyst, which consists of atomically dispersed, nitrogen‐coordinated Co–Co dimers, and Fe single sites (i.e., Co 2 –N 6 and Fe–N 4 structures) that are coanchored on highly graphitized carbon supports is developed. This unique atomic ORR catalyst outperforms the catalysts with only Co 2 –N 6 or Fe–N 4 sites in both alkaline and acid conditions. Density functional theory calculations clearly unravels the synergistic effect of the Co 2 –N 6 and Fe–N 4 sites, which can induce higher filling degree of Fe–d orbitals and favors the binding capability to *OH intermediates (the rate determining step). This ternary‐atom catalyst may be a promising alternative to Pt to drive the cathodic ORR in zinc–air batteries.