Ionic liquid-based electrolysis-deposition for modulating Pb crystal facets to boost CO2 electroreduction

Abstract

The crystal facet of electrodes is one of the main factors affecting the activity of CO₂ electroreduction. Herein, a new ionic liquid (IL)-based electrolysis-deposition (ED) method was developed for modulating the Pb crystal facet to boost CO₂ electroreduction. ED-Pb with an electrodeposition time of 900 s showed a high formate partial current density of 110.8 mA cm⁻² with over 80% formate faradaic efficiency at −2.4 V (vs. Ag/Ag⁺), which is much higher than values using a Pb planar electrode with 19.8 mA cm⁻² partial current density and 70% faradaic efficiency. Experimental results and density functional theory calculations revealed that ED-Pb catalysts have the dominant Pb(111) crystal facet due to the different adsorption energies of the IL on the crystal facet, and the improved performance is attributed to the low Gibbs free energy of OCHO* intermediates on the Pb(111) crystal facet. This work provides a new strategy for regulating the structures of electrocatalysts for high-activity CO₂ electroreduction.