Highly stability Cu+ species in hollow Cu2O nanoreactors by modulating cavity size for CO2 electroreduction to C2+ products
Rui Zhang, Feifei Chen, Haokun Jin, Yong Zhang, Xiaoya Hao, Yingda Liu, Tianming Feng, Xinghua Zhang, Zunming Lu, Weihua Wang, Feng Lu, Hong Dong, Hui Liu, Hui Liu, Yahui Cheng
Abstract
In Cu-based electrocatalysts, appropriate amount of Cu 0 and high concentration of Cu + are essential for the efficient conversion of CO 2 into C 2+ products. An obstacle of CO 2 electroreduction is the inevitable reduction of Cu + to Cu 0 at cathodic potential. Intermediates confinement is a promising solution to delay Cu + deterioration, in which it is crucial to maintain an appropriate amount of Cu 0 and Cu + species to produce sufficient intermediates to protect most Cu + species. Herein, based on the influence of Cu + /Cu 0 ratio on the reaction process and its feedback, a series of hollow Cu 2 O nanoreactors with different cavity sizes were synthesized to modulate the concentration of intermediates and the coverage degree of Cu + , so as to realize a constant high Cu + /Cu 0 ratio. The optimized hollow Cu 2 O nanoreactors achieved a C 2+ Faradaic efficiency of 70.1 ± 0.2 % at a partial current density of −9.3 ± 0.1 mA cm −2 over 30 h and a large C 2+ -to-C 1 ratio of 9.73. Operando Raman spectra and quasi in - situ Auger electron spectra confirmed that the moderate cavity Cu 2 O nanoreactors led to a full coverage of Cu + and an optimal Cu + /Cu 0 ratio of 8.12:1, which brought the stability of Cu + species and cavity structure, as well as the enhanced C C dimerization.