Tailoring the interfacial microenvironment by electrolyte engineering boosts bicarbonate electrolysis

Bicarbonate electrolysis, as a carbon utilization technology with high efficiency and potential for industrial applications, provides a promising pathway for CO₂ emission reduction. However, how to inhibit serious hydrogen evolution reaction (HER) and increase the relatively low CO₂ concentration at the electrode-electrolyte interfacial is challenging. Here, we introduce three typical aminopolycarboxylic acids (APCAs) with different amounts of carboxylic acid roots into 3 M KHCO₃ to enhance the Faradaic efficiency of CO (FE_CO) from 51.2% to 68.0% at 100 mA cm⁻². Spectroscopic characterization confirms that the role of APCAs in confining the activity of water dissociation and improving the availability of CO₂. The strategy adopted in this work that introducing APCAs into the electrolyte to balance the content of CO₂ and H₂O for improving the electrocatalytic performance, can serve as a reference for other electrocatalytic systems.