Joint tuning the morphology and oxygen vacancy of Cu₂O by ionic liquid enables high-efficient CO₂ reduction to C₂ products
Chemical Engineering Journal
School of Engineering
National Natural Science Foundation of China (21808242, 52072409),
Major Scientific and Technological Innovation Project of Shandong Province (2020CXGC010403),
Foundation of State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering (2020-KF-31)
The electrochemical CO2 reduction to multi-carbon products is a promising way for tackling carbon emissions and restoring renewable electricity, which still lacks of efficient electrocatalysts. Herein, Cu₂O nanoparticles with rough surface and abundant oxygen vacancies were facilely prepared by using an ionic liquid, [Omim]Cl (1-octyl-3-methylimidazolium chloride), as a bifunctional structure-directing agent, where the [Omim]+ played a role of surfactant to adjust the morphology of Cu₂O and the Cl‾ facilitated the formation of oxygen vacancies by coordination with Cu+. The obtained Cu₂O nanoparticles were further dispersed on the home-made graphite nanosheets to fabricate a composite catalyst, which showed an excellent catalytic performance with high faradaic efficiency of C₂ (78.5 ± 2%) and commercial-level current density (123.1 mA cm−2) at − 1.1 V vs. RHE for 100 h in a flow cell. In situ surface-enhanced Raman spectroscopy and density functional theory calculations proved the special structure of Cu₂O strengthened the adsorption of intermediates (CO₂•−, CO*) and the following C–C coupling reaction, thus remarkably promoting the formation of C₂ products. This work affords a novel strategy to synthesize metal oxide with controllable morphology and defects for electrochemical applications.