Complementary Operando Spectroscopy identification of in-situ generated metastable charge-asymmetry Cu2-CuN3 clusters for CO2 reduction to ethanol
Xiaozhi Su, Zhuoli Jiang, Jing Zhou, Hengjie Liu, Danni Zhou, Huishan Shang, Xingming Ni, Zheng Peng, Fan Yang, Wenxing Chen, Zeming Qi, Dingsheng Wang, Yu Wang
Abstract
Abstract Copper-based materials can reliably convert carbon dioxide into multi-carbon products but they suffer from poor activity and product selectivity. The atomic structure-activity relationship of electrocatalysts for the selectivity is controversial due to the lacking of systemic multiple dimensions for operando condition study. Herein, we synthesized high-performance CO 2 RR catalyst comprising of CuO clusters supported on N-doped carbon nanosheets, which exhibited high C 2+ products Faradaic efficiency of 73% including decent ethanol selectivity of 51% with a partial current density of 14.4 mA/cm −2 at −1.1 V vs. RHE. We evidenced catalyst restructuring and tracked the variation of the active states under reaction conditions, presenting the atomic structure-activity relationship of this catalyst. Operando XAS, XANES simulations and Quasi-in-situ XPS analyses identified a reversible potential-dependent transformation from dispersed CuO clusters to Cu 2 -CuN 3 clusters which are the optimal sites. This cluster can’t exist without the applied potential. The N-doping dispersed the reduced Cu n clusters uniformly and maintained excellent stability and high activity with adjusting the charge distribution between the Cu atoms and N-doped carbon interface. By combining Operando FTIR and DFT calculations, it was recognized that the Cu 2 -CuN 3 clusters displayed charge-asymmetric sites which were intensified by CH 3 * adsorbing, beneficial to the formation of the high-efficiency asymmetric ethanol.