Supercritical CO<sub>2</sub>-assisted rapid synthesis of covalent organic framework-based electrocatalyst for efficient two-electron oxygen reduction reaction.

Song, Junqi; Zhang, Zhiqiang; Li, Weiping; Liu, Chunli; Feng, Guodong; Su, Yaqiong; Xi, Kai; Yi, Hong et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

Covalent organic frameworks (COFs) hold significant promise as electrocatalysts, but their synthesis is typically constrained by prolonged reaction times (>72 h), high temperatures ( >120 °C), and the use of organic solvents. Conventional methods also involve multiple freeze-pump-thaw cycles, complicating scalability. Herein, we report a supercritical carbon dioxide (Sc-CO<sub>2</sub>)-assisted strategy for the rapid synthesis of COFs, enabling their direct in-situ growth on carbon substrates. This supercritical-solvothermal approach yields COF@CNT composites that exhibit effective electrocatalytic performance towards the two-electron oxygen reduction reaction (2e<sup>-</sup> ORR). The resulting catalysts achieve a H<sub>2</sub>O<sub>2</sub> production rate of 94 mol g<sub>cat</sub><sup>-1</sup> h<sup>-1</sup> and a Faradaic efficiency exceeding 95% at 800 mA cm<sup>-2</sup>. By reducing the consumption of organic solvents, shortening reaction durations, and circumventing high temperatures, this method provides a scalable and efficient route for COF synthesis. Overall, the Sc-CO<sub>2</sub> strategy provides a promising platform for the rapid development of COF-based electrocatalysts, combining enhanced efficiency, scalability, and environmental compatibility.