Manoeuvring organo-electrocatalytic selective CO2 reduction to CO by terpyridine derivatives: DFT mechanistic exploration

Abstract

The field of sustainable energy is rapidly growing, with electro-catalytic CO₂ reduction becoming a key focus. This study examines the effectiveness of substituted terpyridine derivatives (L1–L6) as electrocatalysts for CO₂ reduction in a DMF and H₂O mixture. Using polypyridyl ligands for CO₂ electrochemical transformation into valuable products is relatively rare. Our investigation shows that terpyridine ligands are highly effective in converting CO₂ into CO and H₂via a 2H⁺/2e⁻ reduction process, with an overpotential of 650 to 850 mV vs. SCE. Notably, catalyst L6 demonstrated impressive faradaic efficiency (FE) for CO and H₂, with 74% and 0.04% at −1.8 V vs. SCE, respectively, after 3 hours of electrolysis. All these catalysts, L1–L6, exhibit over 90% selectivity for CO generation. The DFT studies reveal that the mechanism follows EECC pathways, where ‘E’ represents electrochemical steps and ‘C’ denotes chemical steps.