Fast and Stable Electrochemical Production of H2O2by Electrode Architecture Engineering

Abstract

Fast and stable production of hydrogen peroxide (H2O2) through electrochemical pathways is crucial for wastewater treatment applications. With this objective, herein, we report an integrated and superaerophilic electrode composed of atomically dispersed Ni-O-C site-enriched carbon nanosheets (IS-NiOC electrode) for electrochemical oxygen reduction to produce H2O2. Both experimental and theoretical results have proven that atomically dispersed Ni-O-C sites enable a low overpotential (260 mV at 0.1 mA cm-2) and high selectivity (>90% at 0.0-0.5 V vs reversible hydrogen electrode (RHE)) in a neutral electrolyte. Compared with a commercial gas-diffusion electrode, the IS-NiOC electrode offers stronger affinity to oxygen bubbles and more robust three-phase contact points, resulting in high current density (∼106 mA cm-2 at 0.25 V vs RHE) and superior stability (∼200 h). These merits allow the application of the IS-NiOC electrode in an electro-Fenton-like process, which enables fast degradation of representative organic pollutants in both a steady state and a flow state.