hydrophobic nature of phenyl substituents and the presence of residual water in the electrolyte, it is plausible to propose that the stability and catalytic performance of the MM cation are influenced by the interaction between residual water and the cation in the electric double layer. We anticipate that the presence of residual water, which is more prevalent in the case of more hydrophilic cations like MM, will have an impact on the stability of the MM cation. This hypothesis is supported by the findings of Amit et al.6 , who demonstrated that the reduction of water in the vicinity of the electrode surface can generate hydroxyl groups. These hydroxyl groups can subsequently lead to the deprotonation of nearby imidazolium cations as well as the potential decoration of the electrode with the conjugate base of the cation (Figure 4.8). As discussed by Amit et al., the extent of deprotonation and its impact on the cation's behavior will be influenced by the specific nature of the cation and the abundance of hydroxyl groups at the electrode surface. Taking this chemical understanding into account, the gradual increase in overpotential observed with the MM cation (Figure 4.7) can likely be attributed to the partial deactivation of the MM cation caused by the reduction of residual water in the electric double layer (EDL). It's also essential to acknowledge that the MM cation has consistently been a commercially available entity in this study, potentially subjected to different drying procedures compared to the rigorous processes applied to in-house synthesized cations like DiPh. Consequently, the likelihood of increased water presence on the electrode surface, accompanied by the MM cation, is a noteworthy consideration. It's worth noting that this hypothesis could Figure 4.8. The deprotonation of imidazolium cation in presence of active surface hydroxyl group at the vicinity of the electrode. Proposed by Amit et al.6
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