Electrochemically synthesized H<sub>2</sub>O<sub>2</sub> at industrial-level current densities enabled by in situ fabricated few-layer boron nanosheets.

Wu, Yuhan; Zhao, Yuying; Yuan, Qixin; Sun, Hao; Wang, Ao; Sun, Kang; Waterhouse, Geoffrey I N; Wang, Ziyun et al. · Nat Commun · 2024

basic_science · Level V

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Abstract

Carbon nanomaterials show outstanding promise as electrocatalysts for hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) synthesis via the two-electron oxygen reduction reaction. However, carbon-based electrocatalysts that are capable of generating H<sub>2</sub>O<sub>2</sub> at industrial-level current densities (>300 mA cm<sup>-2</sup>) with high selectivity and long-term stability remain to be discovered. Herein, few-layer boron nanosheets are in-situ introduced into a porous carbon matrix, creating a metal-free electrocatalyst (B<sub>n</sub>-C) with H<sub>2</sub>O<sub>2</sub> production rates of industrial relevance in neutral or alkaline media. B<sub>n</sub>-C maintained > 95% Faradaic efficiency during a 140-hour test at 300 mA cm<sup>-2</sup> and 0.1 V vs. RHE, and delivered a mass activity of 25.1 mol g<sub>catalyst</sub><sup>-1</sup> h<sup>-1</sup> in 1.0 M Na<sub>2</sub>SO<sub>4</sub> using a flow cell. Theoretical simulations and experimental studies demonstrate that the superior catalytic performance originates from B atoms with adsorbed O atoms in the boron nanosheets. B<sub>n</sub>-C outperforms all metal-based and metal-free carbon catalysts reported to date for H<sub>2</sub>O<sub>2</sub> synthesis at industrial-level current densities.