Electrochemically synthesized H2O2 at industrial-level current densities enabled by in situ fabricated few-layer boron nanosheets
Yuhan Wu, Yuying Zhao, Qixin Yuan, Hao Sun, Ao Wang, Kang Sun, Geoffrey I. N. Waterhouse, Ziyun Wang, Jingjie Wu, Jianchun Jiang, Mengmeng Fan
Abstract
Carbon nanomaterials show outstanding promise as electrocatalysts for hydrogen peroxide (H2O2) synthesis via the two-electron oxygen reduction reaction. However, carbon-based electrocatalysts that are capable of generating H2O2 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 (Bn-C) with H2O2 production rates of industrial relevance in neutral or alkaline media. Bn-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 gcatalyst−1 h−1 in 1.0 M Na2SO4 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. Bn-C outperforms all metal-based and metal-free carbon catalysts reported to date for H2O2 synthesis at industrial-level current densities. Carbon nanomaterials show promise for H2O2 synthesis, but carbon electrocatalysts with industrial-level performance and stability require more research. Here the authors report few-layer boron nanosheets for H2O2 electrochemical production with > 95% Faradaic efficiency during 140-hour test at 300 mA cm-2.