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

Liu, Longxiang; Kang, Liqun; Feng, Jianrui; Hopkinson, David G; Allen, Christopher S; Tan, Yeshu; Gu, Hao; Mikulska, Iuliia et al. · Nat Commun · 2024

basic_science · Level V

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Abstract

Electrochemical hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) production (EHPP) via a two-electron oxygen reduction reaction (2e<sup>-</sup> 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 × 10<sup>5 </sup>A g<sub>Co</sub><sup>-1</sup> at 0.5 V vs. RHE), and a high practical H<sub>2</sub>O<sub>2</sub> production rate (4.72 mol g<sub>catalyst</sub><sup>-1</sup> h<sup>-1</sup> cm<sup>-2</sup>). Compared with the popularly recognized square-planar symmetric Co-N<sub>4</sub> configuration, the superiority of asymmetric Co-C/N/O configurations is elucidated by X-ray absorption fine structure spectroscopy analysis and computational studies.