Dynamic Activation of Edge-Hosted Co–N<sub>4</sub> Sites for Energy-Efficient Electrochemical CO<sub>2</sub> Reduction at Industry-Level Current Density
Cai Wang, Bairong Chen, Qiyou Wang, Hanchi Hu, Runlin Xia, Jiexin Zhu, Qian Sun, Zhi‐Zheng Wu, Rui Kai Miao, Qingxin Guan, Yuping Liu, Min Liu, Wei Li
Abstract
Achieving energy-efficient electrochemical CO 2 reduction (ECR) at an industry-level current density is both critically important and highly challenging, as it requires simultaneously maintaining high product selectivity and low overpotential under such demanding conditions. In this study, we present a single-atom Co–N–C catalyst with superior selectivity and activity for CO production at a low overpotential in ECR, enabled by the design of edge-hosted Co–N 4 sites. The combined results of theoretical calculations and in situ characterizations reveal that axial *CO coordination forms dynamically on edge-hosted Co–N 4 sites (CoN 4 C 8 –CO) during the ECR process. The CoN 4 C 8 –CO structure as an active site modulates the density of states of the Co atom, reduces the free energy barrier for *COOH formation, and also makes the CO desorption easy, thereby promoting CO 2 -to-CO conversion. As a result, the catalyst demonstrates a CO selectivity exceeding 99% at current densities of 600 mA cm –2 in a flow cell and 500 mA cm –2 in a membrane electrode assembly (MEA), respectively. Impressively, the MEA device demonstrates a high cell energy efficiency of up to 70.8% at 200 mA cm –2 and 55.7% at 500 mA cm –2 toward CO production, demonstrating great advantages compared with other state-of-the-art electrocatalysts.