Surfactant-modified electrode-electrolyte interface for steering CO₂ electrolysis on Cu electrodes

Cu-based catalysts exhibit the unique ability to generate high-order products from electrochemical CO2 reduction reaction (CO2RR). The performance of electrochemical systems is jointly influenced by the catalysts and local microenvironment of the electrode-electrolyte interface. Here, Cu nanowires as a model catalyst, in combination with cetyl trimethyl ammonium bromide (CTAB) as electrolyte additives, are designed to steer CO2RR. By using the Cu rotating disc electrode and in situ vibrational spectroscopy, it is revealed that the hydrophobic interface microenvironment is built, and the interaction of interfacial water and surface-adsorbed CO is disrupted by CTAB, which dramatically improve formate selectivity (from 5% to 63%) with a high partial current density of formate (13-fold increase) at -1.0 V vs. reversible hydrogen electrode. The understanding of the surfactant-modified electrode-electrolyte interface established here offers a distinct perspective to control the microenvironment on promoting electrosynthesis performance.