Promoting Electrocatalytic Reduction of CO 2 to C 2 H 4 Production by Inhibiting C 2 H 5 OH Desorption from Cu 2 O/C Composite.

The electrochemical CO 2 reduction reaction (CO 2 RR) has great potential in realizing carbon recycling while storing sustainable electricity as hydrocarbon fuels. However, it is still a challenge to enhance the selectivity of the CO 2 RR to single multi-carbon (C 2+ ) product, such as C 2 H 4 . Here, an effective method is proposed to improve C 2 H 4 selectivity by inhibiting the production of the other competitive C 2 products, namely C 2 H 5 OH, from Cu 2 O/C composite. Density functional theory indicates that the heterogeneous structure between Cu 2 O and carbon is expected to inhibit C 2 H 5 OH production and promote CC coupling, which facilitates C 2 H 4 production. To prove this, a composite electrode containing octahedral Cu 2 O nanoparticles (NPs) (o-Cu 2 O) with {111} facets and carbon NPs is constructed, which experimentally inhibits C 2 H 5 OH production while strongly enhancing C 2 H 4 selectivity compared with o-Cu 2 O electrode. Furthermore, the surface hydroxylation of carbon can further improve the C 2 H 4 production of o-Cu 2 O/C electrode, exhibiting a high C 2 H 4 Faradaic efficiency of 67% and a high C 2 H 4 current density of 45 mA cm -2 at -1.1 V in a near-neutral electrolyte. This work provides a new idea to improve C 2+ selectivity by controlling products desorption.