Atomically Dispersed Nickel(I) on an Alloy‐Encapsulated Nitrogen‐Doped Carbon Nanotube Array for High‐Performance Electrochemical CO<sub>2</sub> Reduction Reaction
Tianyu Zhang, Han Xu, Hongbin Yang, Aijuan Han, Enyuan Hu, Yaping Li, Xiao‐Qing Yang, Lei Wang, Junfeng Liu, Bin Liu
Abstract
Abstract Single‐atom catalysts (SACs) show great promise for electrochemical CO 2 reduction reaction (CRR), but the low density of active sites and the poor electrical conduction and mass transport of the single‐atom electrode greatly limit their performance. Herein, we prepared a nickel single‐atom electrode consisting of isolated, high‐density and low‐valent nickel(I) sites anchored on a self‐standing N‐doped carbon nanotube array with nickel–copper alloy encapsulation on a carbon‐fiber paper. The combination of single‐atom nickel(I) sites and self‐standing array structure gives rise to an excellent electrocatalytic CO 2 reduction performance. The introduction of copper tunes the d‐band electron configuration and enhances the adsorption of hydrogen, which impedes the hydrogen evolution reaction. The single‐nickel‐atom electrode exhibits a specific current density of −32.87 mA cm −2 and turnover frequency of 1962 h −1 at a mild overpotential of 620 mV for CO formation with 97 % Faradic efficiency.