Facilitating electrocatalytic CO₂ reduction through electrolyte additives accompanied by activation of copper electrode with cyclic voltammetry

Electrode materials have an important impact on the efficiency and product selectivity of electrocatalytic CO₂ reduction, and copper is favored as an electrode material capable of generating a variety of multicarbon products. However, its poor product selectivity limits its large-scale application. In order to regulate the selectivity to certain products, 1,2-cyclohexylenedinitrilotetraacetic acid (CyDTA) was employed as electrolyte additive to form Cu–N active sites by ligand chelation with copper, which improved the selectivity of CH₄. Furthermore, the electrode modification was enhanced with activation using cyclic voltammetry (CV), and the results showed that the CV activation significantly strengthened the interaction between CyDTA and copper electrode, which led to the highest partial current density up to 9.3 mA cm⁻² of CH₄ in an H-type electrolytic cell at an electrode potential of − 1.0 V (vs. RHE). Under this condition, the Faradaic efficiency of CH₄ was up to 74% and could be kept more than 50% after 8-h constant potential electrolysis. The results of this study provided a new strategy to improve the selectivity of CO₂ reduction products with copper electrode, which can promote the wide application of electrocatalytic CO₂ reduction process.