CO2 To Formic Acid Conversion

Dioxide Materials Proves Long-term Stability of CO2 Conversion Process to Pure Formic Acid

CO2 to Formic Acid conversion was conducted with Dioxide Materials’ three-compartment electrolyzer design and the results are published in the Journal of CO2 Utilization. The results prove that long-term stability of CO2 conversion process to high value pure formic acid.

The electrolyzer can be operated at current density as high as 300 mA cm-2, with a voltage below 4.0 V. No significant change in formic acid FE’s were observed at current densities between 100 and 250 mA cm-2, while the formic acid product concentration increased with current density at a constant DI water flow rate into the center compartment. The highest formic acid FE of 91.3 % was achieved using a center compartment DI water flow rate of 0.17 mL min-1, with 6.03 wt% formic acid product.

A 1000 h long-term test was then conducted at a 200 mA cm-2 current density resulting with formic acid FE mostly above 70% and formic acid concentration above 11 wt% during 1000 h of operation. It was found that metallic Bi and Bi2O2CO3 were formed on the cathode catalyst after long-term testing. The SEM shows that minimum change in the morphology apart from that caused by pressing in the cell setup.

Figure: SEM images of cathode before (a, b) and after (c, d) 1000 h long-term testing.

The current results demonstrate the long-term stability of 1000 h operation of the three-compartment design CO2 to formic acid electrolyzer at industrially relevant current densities with high formic acid product concentration and high formic acid FE’s. The electrolyzer design and data provide a pathway in the commercialization of electrochemical CO2 reduction to formic acid.

This publication builds on our previous works. The results are bolstered by use of Dioxide Materials proprietary Sustainion anion conducting membrane. The membrane along with the complete working cell and components can be purchased from our webstore