Cathodic Conversion of Pressurized CO2 at Silver Cathodes: What are the Optimal Values of Pressure and Current Density?

The cathodic reduction of pressurized CO2 (PrCO2CR) at suitable cathodes can allow to produce various chemicals, such as formic acid/formate (FA) and carbon monoxide or synthesis gas, with high faradic efficiencies (FEs) and productivities. Here, we have performed the conversion of CO2 in an undivided pressurized electrochemical reactor using silver cathode in order to determine the optimal values of CO2 pressure and current density. It was found that the plot FE vs. pressure resulted in a curve with a maximum. Similarly, an optimal value of current density can be selected for the PrCO2CR. The competition between the production of carbon monoxide and formic acid/formate is strongly affected by both the pressure and the current density. Eventually the effect of pressure and current density on the economic figures of the process was evaluated.