Atomically dispersed nickel(I) on an alloy‐encapsulated nitrogen‐doped carbon nanotube array for high‐performance electrochemical CO₂ reduction reaction

• Main Authors: Zhang, Tianyu, Han, Xu, Yang, Hongbin, Han, Aijuan, Hu, Enyuan, Li, Yaping, Yang, Xiao‐qing, Wang, Lei, Liu, Junfeng, Liu, Bin
• Other Authors: School of Chemical and Biomedical Engineering
• Format: Article
• Language: English
• Published: 2023
• Subjects: Engineering::Chemical engineering; Electrocatalysis; Nanoarrays
• Online Access: https://hdl.handle.net/10356/170447
• Institution: Nanyang Technological University

Single-atom catalysts (SACs) show great promise for electrochemical CO2 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 CO2 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.