Facilitating two-electron oxygen reduction with pyrrolic nitrogen sites for electrochemical hydrogen peroxide production.

Peng, Wei; Liu, Jiaxin; Liu, Xiaoqing; Wang, Liqun; Yin, Lichang; Tan, Haotian; Hou, Feng; Liang, Ji · Nat Commun · 2023

basic_science · Level V

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Abstract

Electrocatalytic hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) production via the two-electron oxygen reduction reaction is a promising alternative to the energy-intensive and high-pollution anthraquinone oxidation process. However, developing advanced electrocatalysts with high H<sub>2</sub>O<sub>2</sub> yield, selectivity, and durability is still challenging, because of the limited quantity and easy passivation of active sites on typical metal-containing catalysts, especially for the state-of-the-art single-atom ones. To address this, we report a graphene/mesoporous carbon composite for high-rate and high-efficiency 2e<sup>-</sup> oxygen reduction catalysis. The coordination of pyrrolic-N sites -modulates the adsorption configuration of the *OOH species to provide a kinetically favorable pathway for H<sub>2</sub>O<sub>2</sub> production. Consequently, the H<sub>2</sub>O<sub>2</sub> yield approaches 30 mol g<sup>-1</sup> h<sup>-1</sup> with a Faradaic efficiency of 80% and excellent durability, yielding a high H<sub>2</sub>O<sub>2</sub> concentration of 7.2 g L<sup>-1</sup>. This strategy of manipulating the adsorption configuration of reactants with multiple non-metal active sites provides a strategy to design efficient and durable metal-free electrocatalyst for 2e<sup>-</sup> oxygen reduction.