Boosting CO₂ electrocatalysis through electrical double layer regulations

Interfacial investigation for fine-tuning microenvironment has recently emerged as a promising method to optimize the electrochemical CO₂ reduction system. The electrical double layer located at the electrode-electrolyte interface presents a particularly significant impact on electrochemical reactions. However, its effect on the activity and selectivity of CO₂ electrocatalysis remains poorly understood. Here, we utilized two-dimensional mica flakes, a material with a high dielectric constant, to modify the electrical double layer of Ag nanoparticles. This modification resulted in a significant enhancement of current densities for CO₂ reduction and an impressive Faradaic efficiency of 98% for CO production. Our mechanistic investigations suggest that the enhancement of the electrical double layer capacitance through mica modification enriched local CO₂ concentration near the reaction interface, thus facilitating CO₂ electroreduction.