Electrochemical conversion of CO2 to formic acid in a microfluidic device

Since the industrial revolution, due to economic growth, energy demand has gradually increased, thus causing high CO2 emissions [1]. Nowadays, electrochemical conversion of CO2 is considered a relevant topic for several reasons, including the possibility to synthesize chemicals and/or fuels and the decrease of CO2 emissions. The CO2 molecules can be converted by multi-electron transfer reduction in various products by changing the nature of cathodes. The aim of the research is to find the operative conditions which allows to maintain at the same time high current density, high Faradic Efficiency, low energy consumption, long-term stability and to increase the final concentration of liquid products. Various kinds of electrochemical cells were used even if less attention was devoted to microfluid ones. The application of continuous-flow micro-fluidic devices for the synthesis of chemicals received increasing attention in chemical engineering in the last years [2]. In particular, in this study we have investigated the cathodic conversion of CO2 to formic acid at tin cathodes in undivided microfluidic electrochemical cells characterized by very small inter-electrode distances: 250, 120 and 75 μm. The effect of numerous operative parameters such as pH, supporting electrolyte and current density was investigated.