Electrochemically synthesized H(2)O(2) at industrial-level current densities enabled by in situ fabricated few-layer boron nanosheets.

Carbon nanomaterials show outstanding promise as electrocatalysts for hydrogen peroxide (H(2)O(2)) synthesis via the two-electron oxygen reduction reaction. However, carbon-based electrocatalysts that are capable of generating H(2)O(2) at industrial-level current densities (>300 mA cm(-2)) 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(n)-C) with H(2)O(2) production rates of industrial relevance in neutral or alkaline media. B(n)-C maintained > 95% Faradaic efficiency during a 140-hour test at 300 mA cm(-2) and 0.1 V vs. RHE, and delivered a mass activity of 25.1 mol g(catalyst)(-1) h(-1) in 1.0 M Na(2)SO(4) 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(n)-C outperforms all metal-based and metal-free carbon catalysts reported to date for H(2)O(2) synthesis at industrial-level current densities.