N<i>x</i>C-Induced Switching of Methane and Ethylene Products’ Selectivity from CO<sub>2</sub> Electroreduction over Cu Catalyst
Yanjia Cui, Chao Kong, Caili Yang, Yingshi Su, Yonghui Cheng, Defu Yao, Guanli Chen, Kangjin Song, Ziyi Zhong, Ying Song, Gongwei Wang, Zhen Li, Lin Zhuang
Abstract
Regulating the electronic properties or morphology feature of CO 2 electroreduction catalysts can maintain selectivity toward certain reduction products. Here we report a nitrogen doped carbon (N x C) modification strategy that can switch CH 4 and CH 2 CH 2 product selectivity during CO 2 electrolysis over the Cu catalyst. The fabricated core–shell Cu@N x C catalyst exhibited good performance in suppressing HER and promoting CO 2 RR. About 90% FEs was achieved over the Cu@N x C-350 °C (10:4) catalyst, of which the CH 2 CH 2 FEs was 54% at −1.4 V vs RHE. However, the C 1 product was the majority over the Cu@N x C-400 °C (10:4) catalyst, and 63% FEs of CH 4 was achieved at the same applied potential. The in-depth characterization revealed that the remarkable selectivity switching of CH 4 and CH 2 CH 2 products originated from the N x C shell, rather than the change in the electronic feature of the Cu core. The more pyrrolic N contained in the Cu@N x C catalyst tended to form bridge-bonded *CO, leading to a dominant CH 4 product, while the more pyridinic N contained in the Cu@N x C catalyst tended to form linearly bonded *CO, which was favorable for C–C coupling to form the CH 2 CH 2 product. Our results provided insights into the role of the chemical environment on CO 2 electroreduction processes.