Figure 7.3 illustrates the electrolysis results using Cs NTf2 electrolytes for CO2 reduction in anhydrous MeCN. We observed a substantial increase in cell voltage over time, indicating an instability in the electrochemical system. Additionally, the faradaic efficiency for CO formation was found to be very poor, with up to 90 percent of electrons consumed for hydrogen production. The observed instability in the potential, which extends beyond the electrochemical window of acetonitrile137, is consistent with the inability of Au electrodes to reduce CO2 in the absence of imidazolium cations. This increasingly higher potential may imply the degradation of acetonitrile138 which contributes to the current and the formation of H2. These observations highlight the inability of alkali metal electrolytes to allow for CO2 reduction in non-aqueous media. The results of this study contrast with the literature findings on the positive impact of alkali metal cations for electrochemical CO2 reduction in aqueous media 18, 139. Koper et al.49 argue that the absence of alkali metal cations prevents CO2 reduction over Au, Ag, and Cu electrodes in aqueous media. They suggested that partially desolvated alkali metal cations present in the electronic double layer stabilize the high-energy CO2 radical intermediate through short-range Figure 7.3. Electrolysis Results for CO2 Reduction at -1 mA/cm2 with 0.5 mol% of Cs NTf 2 on Au Working Electrode. (a) Timedependent instability observed in the cell potential profile during electrolysis. (b) Limited faradaic efficiency for CO formation, reaching only up to 10%. Additionally, noticeable fluctuations are observed in the potential profile. a b
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