Promoting Electrochemical CO<sub>2</sub> Reduction via Boosting Activation of Adsorbed Intermediates on Iron Single‐Atom Catalyst
Jiayi Chen, Tingting Wang, Xinyue Wang, Bin Yang, Xiahan Sang, Sixing Zheng, Siyu Yao, Zhongjian Li, Qinghua Zhang, Lecheng Lei, Jiang Xu, Liming Dai, Yang Hou
Abstract
Abstract Single‐atom catalysts show great promise as non‐precious electrocatalysts for CO 2 electroreduction reaction (CO 2 ER). However, it is still challenging to gain a fundamental understanding of the complicated dynamic behavior of CO 2 activation to achieve high product selectivity. Herein, the authors report an unusual iron single‐atom catalyst, containing atomically dispersed Fe–N 4 species and Fe 3 C nanoparticles (NPs) (Fe 3 C|Fe 1 N 4 ). Having a fragmental‐rock‐shaped nanocarbon architecture, isolated Fe–N 4 sites uniformly disperse with adjacent Fe 3 C NPs (<30 nm) in a carbon matrix. Benefiting from the strong coupling effect between Fe 3 C and Fe 1 N 4 and unique spatial nanostructure, Fe 3 C|Fe 1 N 4 displays exceptional CO 2 ER activity with a low onset potential of −0.3 V and high Faradaic efficiency of 94.6% at −0.5 V for CO production, acting as one of the most active Fe–N–C catalysts and even exceeding most other carbon supported non‐precious metal NPs. Experimental observations discover that the excellent CO 2 ER activity of Fe 3 C|Fe 1 N 4 catalyst is attributable to the presence of Fe 3 C NPs that optimizes J CO of the coexisted Fe–N 4 active sites. In situ attenuated total reflectance‐Fourier transform infrared analysis and theoretical calculations reveal that the Fe 3 C NPs strengthen the adsorption of CO 2 on the isolated Fe–N 4 sites to accelerate the formation of *COOH intermediate, and hence enhance the whole CO 2 ER performance.