Protein-mediated synthesis of iron single atom electrocatalyst with highly accessible active sites for enhanced pH-universal oxygen reduction

Facile synthesis of highly efficient non-precious metal electrocatalysts is intriguing as these catalysts are used in the oxygen reduction reaction (ORR). Herein, we describe an effective protein-mediated approach to access atomically dispersed iron electrocatalyst (Fe SAs/NC) with enhanced accessible metal active sites. This Fe catalyst achieves an exceptional ORR activity in the pH-universal range, especially in alkaline and acid electrolytes with half-wave potentials of 0.93 and 0.84 V (vs RHE), respectively. The unique electronic structure of Fe sites with enhanced electron/proton transportation ability contributes to the optimized adsorption/desorption of oxygen intermediates. In addition, it shows robust durability and excellent tolerance to methanol crossover in pH-universal media. Impressively, it displays encouraging performance when employed in a zinc-air battery, demonstrating a peak power density of 275.1 mW cm−2 and a specific capacity of 753.8 mAh g−1. The extremely long-term operational stability of more than 250 h further provides significant potential for its application. [Display omitted] •Fe single atoms supported over nitrogen-doped carbon was created.•DFT calculations reveal the support can provide anchoring sites for Fe atoms.•This catalyst shows high catalytic efficacy in oxygen reduction reaction.•The high catalytic activity stems from electronic metal-support interaction.