Post-oxidation of all-organic electrocatalysts to promote O−O coupling in water oxidation
Chun‐Ting He, Lihong Yu, Haiming Liu, Qing Wang, Zi‐Ming Ye, Jia Zhang, Lidong Wang, Mingxuan He, Xuefeng Zhang, Hong‐Gang Du, Ziwei Lu, Jianfeng Yang, Haihua Huang, Xiao‐Ming Chen
Abstract
Covalently bonded metal-free electrocatalysts exhibit significant potential for sustainable energy technologies, yet their performances remain unsatisfactory compared with metal-based catalysts. Herein, we propose an all-organic electrocatalyst, MEC-2, that conforms to the infrequent oxide path mechanism in alkaline oxygen evolution reaction through post-oxidation modification. MEC-2 achieves an intrinsic overpotential of 257.7 ± 0.6 mV at 10 mA·cm−2 and possesses durability with negligible degradation over 100,000 CV cycles or 250 h of operation at 1.0 A·cm−2, being comparable to the advanced metal-based OER electrocatalysts. The 18O-labeled operando characterization and theoretical calculations unveil that post-oxidation modification enhances the electron affinity to OH intermediates, and adjusts the adsorption configuration and proximity distance of O intermediates, thereby promoting direct O−O radical coupling. In this work, we show a fresh perspective for understanding the role of non-metallic elements/functional groups in electrocatalysis, and to a certain extent, narrows the gap between all-organic electrocatalysts and metal-based electrocatalysts. Metal-free catalysts offer a sustainable option for water oxidation but typically underperform compared to metal-based ones. Here, the authors report an all-organic catalyst that uses a rare oxide pathway to achieve high efficiency and long-term stability, comparable to metal-based systems.