Direct Deposition of Catalysts on Porous Metallic Foams for Efficient CO2 Electroreduction

Intellectual Merit
Energy-efficient upgrading of carbon dioxide (CO2) to carbon monoxide (CO) has the potential to mitigate anthropogenic emissions and support near-term profits. Industrial electrolysis of gaseous reactants, such as for CO2 reduction, requires porous gas diffusion electrodes (GDEs) to obtain high conversion rates. Developing durable electrodes that are capable of optimizing the electrochemically active surface area is crucial for economic feasibility.

Left: Gold (Au) catalyst layer between a porous carbon gas diffusion electrode (GDE) that distributes gases and a flowing electrolyte stream that enables integration of a reference electrode into the cell. While high CO:H2 selectivities are maintained for 50 hours, over time the liquid electrolyte floods the GDE hampering reactant transport to the active sites and reduced electrode performance. Top right: Faradaic efficiency towards forming CO is initially greater than 90% with only slight decay over the course of the experiment. Bottom right: The current density fades from 25 mA/cm2 to 10 mA/cm2.

Broader Impact
The rapidly decreasing cost of wind and solar electricity generation coupled with growing global consensus on the importance of climate change are motivating the electrification of the chemical industry.  

The energy-efficient electrochemical reduction of carbon dioxide (CO2) to carbon monoxide (CO), an important precursor for commodity chemicals and fuels, can mitigate anthropogenic carbon emissions, utilize CO2 as an inexpensive feedstock, and store intermittent renewable electricity in chemical bonds.  Realizing this promise, requires the development of robust, scalable, and cost-effective electrochemical systems necessitating advances in the science and engineering of catalytically-active porous media.

An electrochemical route to synthesis gas (CO + H2), through renewable electricity and carbon waste streams, that may enable pathways to more sustainable production of fuels and commodity chemicals.