A Triatomic Cobalt Catalyst for Oxygen Electrocatalysis

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 tri‐atom cobalt complex precursor onto graphene nanosheets to obtain a triatomic catalyst (Co3‐NG), exhibiting a durable and excellent bifunctional catalyst in the electrocatalytic ORR (Ehalf‐wave = 0.903 V)and OER (Ej=10 = 1.596 V). The Co3‐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 3,000 cycles significantly outperforming the Pt/C+RuO2 benchmark (146.5 mW cm−2, 360 cycles) under testing conditions of 25 °C. In situ XAS analysis and theoretical calculations unclose that Co3ON6 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 center play a key role in improving bifunctional ORR/OER performance for electrochemical energy applications.