Wang, Xiaotong; Wei, Yiheng; Song, Yanfang; Mao, Jianing; Liu, Xiaohu; Li, Shoujie; Li, Guihua; Zhu, Huanyi; Xia, Jiayu; Luo, Cheng; Chen, Aohui; Dong, Xiao; Wei, Wei; Chen, Wei

ADVANCED SCIENCE

2025, 29,

Wang, Xiaotong; Wei, Yiheng; Song, Yanfang; Mao, Jianing; Liu, Xiaohu; Li, Shoujie; Li, Guihua; Zhu, Huanyi; Xia, Jiayu; Luo, Cheng; Chen, Aohui; Dong, Xiao; Wei, Wei; Chen, Wei

Hollow fiber gas penetration electrodes with a compact hierarchical pore structure have emerged as promising platforms for CO2 electroreduction. However, developing carbon hollow fiber electrodes with efficient CO2 electrocatalytic performance remains unexplored and challenging. Herein, a straightforward strategy is presented to fabricate robust, self-standing carbon hollow fiber electrodes modified with an unsaturated Ni-N-2 coordination structure. This unique hollow fiber electrode configuration effectively enhances the kinetics of CO2 electro-conversion to CO. Both density functional theory (DFT) calculations and experimental studies reveal that the Ni-N-2 structure significantly boosts electrocatalytic activity for CO2 reduction by reducing the energy barrier for the key intermediate COOH* formation. Consequently, the electrode with unsaturated Ni-N-2 coordination realizes a high CO Faradaic efficiency (FE) (>90%) as well as a partial current density of 61 mA cm(-2), much superior to those of saturated Ni-N-4 coordination. In particular, this high performance maintains an exceptional durability for over 100 h, outperforming previously reported carbon supporting electrodes featuring Ni-N-C sites. This work opens new avenues for designing advanced carbon electrode structures with enhanced selectivity and activity for CO2 reduction.