introduced an additional layer of complexity, primarily stemming from the impact of steric hindrance due to the inclusion of bulkier substituents like phenyl functional groups. This factor could potentially impede CO2 diffusion to the catalyst site and hinder the coordination of the C2-H to the CO2 adsorbed on the Au surface. In the case of the most acidic cation, 1,3-dimethyl4,5-dichloro imidazolium, the lowest overpotential for CO2 activation was observed. However, the results of electrolysis remained inconclusive, necessitating further investigation. Thus, a delicate equilibrium between steric and electronic effects (the acidity of the C2-H) must be maintained to ensure the cation's electrochemical reactivity falls within the optimal range for CO2 reduction. The performance of the anhydrous MM-acetonitrile electrolyte for CO2 reduction was further highlighted by achieving 100% faradaic efficiency for CO2 to CO conversion across both noble and non-noble metals, including Zn and Ni, all achieved at relatively low overpotentials (Chapter 5). DFT calculations and electrochemical experiments unveiled a volcano plot, positioning the Au electrode at the apex for the highest performance. Zn and Ni electrodes, representing respectively the lowest and highest CO intermediate adsorption capacities, exhibited relatively diminished activity for CO2 reduction. This volcano plot bore resemblance to the one previously identified in aqueous media. However, the introduction of imidazolium cations appeared to influence the relative catalytic activity between different catalysts, suggesting avenues for future in-depth investigation. Chapter 6 was dedicated to an ATR-FTIR study of the performance of C2-methylated imidazolium cations for non-aqueous CO2 reduction. The main product observed was the formation of CO, with minor byproducts such as formate (likely originating from residual water in these experiments) and oxalate, suggesting the existence of multiple pathways for CO2 reduction when this cation was employed in our system. The formation of CO as the major product was proposed to be accompanied by the generation of carbonate ions (CO3 2-), a
RkJQdWJsaXNoZXIy MTk4NDMw