The use of CO₂ produced from power generation plants as a feedstock for creating valuable products offers a commercially viable strategy to reduce greenhouse gas (GHG) emissions and offset the cost of carbon capture. Despite years of CO₂ conversion research, the development of efficient, robust, and selective heterogeneous CO₂ reduction (CO₂R) catalysts to convert CO₂ into value-added compounds has yet to fully mature. In recent years, CO₂R catalysts have become more sophisticated but still struggle with limited long-term activity. Producing value-added CO₂ products via an electrochemical pathway can greatly depend on current density, Faradaic efficiency, electrode material and loading, and performance and material degradation.

To overcome the aforementioned limitations, development of a novel copper-based catalytic electrochemical system that can be used to convert carbon dioxide (CO₂) to formic acid has been conducted. Formic acid (FA) is a high-value C1 chemical feedstock, but its current production process can require other high-valued chemicals as inputs, including methanol and/or hydrogen. In order to selectively convert CO₂ to FA, Cu-based catalysts are commonly used. The metal-to-oxide interface of these catalysts can be tuned to offer higher peripheral metal-to-oxide interfacial area by alkylamine directed synthesis of morphology controlled metal layers formation on oxides.

The developed process leverages highly conductive mesoporous carbon xerogels electrodes, that have already been demonstrated as excellent supports in fuel cells, with Cu-based catalysts for the electrocatalytic conversion of CO₂. Current results indicate that modifying CX cathodes with CuCo:CeO₂ produces over 2X increase in FA compared only using Cu or CuCo at an operating voltage of -0.75 V vs. Ag/AgCl. Further FA selectivity customization is available in the -0.75 V to -1.0 V vs. Ag/AgCl range. Additionally, increasing the cell pressure from 1 to 3 bar to take advantage of the greater equilibrium concentration of CO₂ increased FA production by over 5X, without compromising the structural integrity of the electrochemical cell.

Ayokunle Omosebi

Appearances