Atomically dispersed asymmetric cobalt electrocatalyst for efficient hydrogen peroxide production in neutral media

Abstract

Electrochemical hydrogen peroxide (H₂O₂) production (EHPP) via a two-electron oxygen reduction reaction (2e^- ORR) provides a promising alternative to replace the energy-intensive anthraquinone process. M-N-C electrocatalysts, which consist of atomically dispersed transition metals and nitrogen-doped carbon, have demonstrated considerable EHPP efficiency. However, their full potential, particularly regarding the correlation between structural configurations and performances in neutral media, remains underexplored. Herein, a series of ultralow metal-loading M-N-C electrocatalysts are synthesized and investigated for the EHPP process in the neutral electrolyte. CoNCB material with the asymmetric Co-C/N/O configuration exhibits the highest EHPP activity and selectivity among various as-prepared M-N-C electrocatalyst, with an outstanding mass activity (6.1 × 10⁵A g_Co⁻¹ at 0.5 V vs. RHE), and a high practical H₂O₂ production rate (4.72 mol g_catalyst⁻¹ h⁻¹ cm⁻²). Compared with the popularly recognized square-planar symmetric Co-N₄ configuration, the superiority of asymmetric Co-C/N/O configurations is elucidated by X-ray absorption fine structure spectroscopy analysis and computational studies.

The relationship between the structural configurations of M-N-C electrocatalysts and their performances in neutral environments has been insufficiently investigated. Here the authors demonstrate that an ultralow metal-loaded Co-N-C electrocatalyst, featuring the asymmetric Co-C/N/O configuration, exhibit exceptional efficiency in electrochemically producing hydrogen peroxide under neutral conditions.