A New Strategy for Accelerating Dynamic Proton Transfer of Electrochemical CO<sub>2</sub> Reduction at High Current Densities
Xinyue Wang, Shaohua Feng, Weichao Lu, Yingjie Zhao, Sixing Zheng, Wanzhen Zheng, Xiahan Sang, Lirong Zheng, Yu Xie, Zhongjian Li, Bin Yang, Lecheng Lei, Shaobin Wang, Yang Hou
Abstract
Abstract Developing single‐atom electrocatalysts with high activity and superior selectivity at a wide potential window for CO 2 reduction reaction (CO 2 RR) still remains a great challenge. Herein, a porous NiNC catalyst containing atomically dispersed NiN 4 sites and nanostructured zirconium oxide (ZrO 2 @Ni‐NC) synthesized via a post‐synthetic coordination coupling carbonization strategy is reported. The as‐prepared ZrO 2 @Ni‐NC exhibits an initial potential of −0.3 V, maximum CO Faradaic efficiency (F.E.) of 98.6% ± 1.3, and a low Tafel slope of 71.7 mV dec −1 in electrochemical CO 2 RR. In particular, a wide potential window from −0.7 to −1.4 V with CO F.E. of above 90% on ZrO 2 @Ni‐NC far exceeds those of recently developed state‐of‐the‐art CO 2 RR electrocatalysts based on NiN moieties anchored carbon. In a flow cell, ZrO 2 @Ni‐NC delivers a current density of 200 mA cm −2 with a superior CO selectivity of 96.8% at −1.58 V in a practical scale. A series of designed experiments and structural analyses identify that the isolated NiN 4 species act as real active sites to drive the CO 2 RR reaction and that the nanostructured ZrO 2 largely accelerates the protonation process of *CO 2 − to *COOH intermediate, thus significantly reducing the energy barrier of this rate‐determining step and boosting whole catalytic performance.