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

Abstract

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.