phenomenon also detected through ATR-FTIR measurements. This carbonate species was hypothesized to be formed by the conversion of a second CO2 molecule, acting as an oxygen acceptor. As for the accompanying anodic reaction, residual water might have undergone conversion to form O2 (along with protons), or alternatively, carbonate ions could have been oxidized to generate CO2 and O2. If the latter reaction prevailed, the electrochemical cycle concluded as follows: Cathode: 4 CO2 + 4e - 2 CO + 2 CO3 2- [eq 8.1] Anode: 2 CO3 2- 2 CO2 + O2 + 4e - [eq 8.2] Overall: 2 CO2 2 CO + O2 [eq 8.3] This hypothesis gained further substantiation through experiments where the degradation of the counter graphite electrode was observed as an alternative sacrificial anodic oxidation upon the introduction of diffusion barriers between the cathode and anode (see Appendix Section A.II). This observation supports an oxidation reaction coupled with CO2 reduction, as was proposed above with carbonate oxidation. In Chapter 7, the investigation focused on examining the impact of alkyl chain length at the C1-position of the C2-hydrogenated cation. It was discovered that longer alkyl chain lengths led to reduced performance in CO2 reduction. This observation aligned with the adverse effects of steric hindrance observed with bulky substituents at the C4 and C5 positions in Chapter 4. Additionally, experiments involving alkali metal cations were conducted for the purpose of comparison with imidazolium cations. However, the results showed very poor performance and even degradation of the electrolyte due to significant overpotential. This phenomenon was attributed to electrode passivation in experiments involving alkali metal cations within the anhydrous media.
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