A Triatomic Cobalt Catalyst for Oxygen Electrocatalysis
Tianmi Tang, Xiaoqin Xu, Xue Bai, Changmin Hou, Tao Gan, Zhenlü Wang, Jingqi Guan
Abstract
Abstract The advancement of rechargeable zinc–air batteries significantly depends on bifunctional oxygen electrocatalysts to provide outstanding oxygen reduction/evolution reaction (ORR/OER) performance. However, it is still challenging to design electrocatalysts with excellent bifunctional activity and stability. Here, we adopt an ultrafast printing method to efficiently embed a triatom cobalt complex precursor onto graphene nanosheets to obtain a triatomic catalyst (Co 3 ‐NG), exhibiting a durable and excellent bifunctional catalyst in the electrocatalytic ORR ( E half‐wave = 0.903 V) and OER ( E j = 10 = 1.596 V). The Co 3 ‐NG‐assembled zinc–air battery can output a maximum power density of 189.0 mW cm −2 at 330 mA cm −2 and can be charged and discharged over 3000 cycles, significantly outperforming the Pt/C + RuO 2 benchmark (146.5 mW cm −2 , 360 cycles) under testing conditions of 25 °C. In situ XAS analysis and theoretical calculations disclose that Co 3 ON 6 is the catalytic site for bifunctional ORR/OER electrocatalysis. The constructed triangular pyramidal active sites effectively regulate the d‐band center and electronic configuration and promote the adsorption/desorption of oxygen intermediates. This work uncovers that the geometry and electronic structure of triatomic active centers play a key role in improving bifunctional ORR/OER performance for electrochemical energy applications.