Synthesis of Tangled Iron-Nitrogen Co-doped Carbon Nanosheets through a Dopamine Coordination Strategy for the Oxygen Reduction Reaction

Graphical In a tangle : Benefiting from the unique hierarchical porous structures and abundant Fe−Nx active sites, the tangled Fe−N−C nanosheets prepared through a facile dopamine-coordination strategy can be utilized as high-performance oxygen reduction reaction electrocatalysts. Developing efficient, economical, and durable transition metal atom-dispersed catalysts to boost the sluggish oxygen reduction reactions (ORRs) is crucial for the practical metal-air batteries. Herein, a facile dopamine-coordination strategy was developed to obtain tangled Fe, N co-doped ultrathin carbon nanosheets (donated as tangled Fe−N−C nanosheets), which can be utilized as high-performance ORR electrocatalysts. Benefited from the unique hierarchical porous structures and abundant Fe−N x active sites, the tangled Fe−N−C nanosheets exhibited excellent ORR activity in alkaline medium with more positive half-wave potential (0.88 V vs. RHE) than 20 wt % Pt/C (0.84 V vs. RHE). Meanwhile, the tangled Fe−N−C nanosheets exhibit excellent long-term stability and good tolerance to methanol crossover. When applying the Fe−N−C nanosheets as the cathode catalyst for primary zinc-air batteries (ZABs), the assembled cells exhibit high open circuit voltage (∼1.43 V), high peak power density (∼89 mW cm −2 ) and large specific capacity of 801 mA h g −1 .