Atomically dispersed Co₂ -N₆ and Fe-N₄ costructures boost oxygen reduction reaction in both alkaline and acidic media

• Main Authors: Wang, Zhe, Jin, Xiaoyan, Zhu, Chao, Liu, Yipu, Tan, Hua, Ku, Ruiqi, Zhang, Yongqi, Zhou, Liujiang, Liu, Zheng, Hwang, Seong-Ju, Fan, Hong Jin
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2022
• Subjects: Engineering::Materials; Metal–Air Batteries; Oxygen Reduction Reaction
• Online Access: https://hdl.handle.net/10356/154780
• Institution: Nanyang Technological University

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., Co2 -N6 and Fe-N4 structures) that are coanchored on highly graphitized carbon supports is developed. This unique atomic ORR catalyst outperforms the catalysts with only Co2 -N6 or Fe-N4 sites in both alkaline and acid conditions. Density functional theory calculations clearly unravels the synergistic effect of the Co2 -N6 and Fe-N4 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.