Anhydrous Electrochemistry: Methods and Considerations The main objective of this study was to investigate the co-catalyzed reduction of CO2 by imidazolium cations over Au electrodes in the absence of water. To ensure anhydrous conditions throughout our experiments, significant emphasis was placed not only on maintaining anhydrous conditions during preparation, but also throughout the entire course of the experiments. To achieve this, a detailed protocol was established and elaborated on in this section, which ensured relatively consistent water content (<50 ppm). This was essential to ensure the integrity of the results and prevent any interference from variations in water content on the performance and assessment of the reaction mechanism. Throughout this chapter, a model system consisting of 1,3-dimethyl imidazolium NTf2 (MM NTf2) in anhydrous acetonitrile was employed to investigate the experimental approach. The performance of the MM cation in promoting CO2 reduction will be discussed in detail in Chapter 3. Electrodes and reactor. For each electrolysis measurement, the electrodes underwent an initial polishing process using sandpaper until a smooth and shiny surface was achieved. In the case of voltammetry electrodes, a polishing pad (Prosense, QVMF 1040) was moistened with ethanol and the electrode was gently polished for a duration of 4 minutes (no alumina was utilized on the polishing pad). Subsequently, the electrodes were thoroughly rinsed with MilliQ water (Milli-Q® Reference, 18.2 M, 5 ppb TCO, Merc) and subjected to a 10-minute sonication in 0.5 molar HNO3. Following this step, another round of sonication in ethanol was performed, concluding with a 10-minute sonication in HPLC grade acetonitrile (99.9%, Sigma Aldrich) to ensure the electrodes' cleanliness. It is important to note that the electrodes were always rinsed with Milli-Q water between each sonication step. Noble electrodes such as Au underwent additional electrochemical cleaning (Supporting Information Section III) as necessary. However, general electrochemical cleaning as proposed
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