Topological transformation of microbial proteins into iron single-atom sites for selective hydrogen peroxide electrosynthesis
Xiaofeng Xiao, Zechao Zhuang, Shuhu Yin, Jiexin Zhu, Tao Gan, Ruohan Yu, Jinsong Wu, Xiaochun Tian, Yanxia Jiang, Dingsheng Wang, Feng Zhao
Abstract
The emergence of single-atom catalysts offers exciting prospects for the green production of hydrogen peroxide; however, their optimal local structure and the underlying structure–activity relationships remain unclear. Here we show trace Fe, up to 278 mg/kg and derived from microbial protein, serve as precursors to synthesize a variety of Fe single-atom catalysts containing FeN5−xOx (1 ≤ x ≤ 4) moieties through controlled pyrolysis. These moieties resemble the structural features of nonheme Fe-dependent enzymes while being effectively confined on a microbe-derived, electrically conductive carbon support, enabling high-current density electrolysis. A comparative analysis involving catalysts derived from eleven representative microbes reveals that the presence of 0.05 wt% Fe single-atom sites leads to a significant 26% increase in hydrogen peroxide selectivity. Remarkably, the optimal catalyst featuring FeN3O2 sites demonstrates a selectivity of up to 93.7% and generates hydrogen peroxide in a flow cell at an impressive rate of 29.6 mol g−1 h−1 at 200 mA cm−2. This work achieves structural fine-tuning of metal single-atom sites at the trace level and provides topological insights into single-atom catalyst design to achieve cost-efficient hydrogen peroxide production. Single-atom catalysts hold great potential for the electrochemical oxygen reduction reaction in hydrogen peroxide production. Here, the authors report Fe single-atom catalysts derived from microbial protein precursors, which enhance both the selectivity and activity for hydrogen peroxide production.