Due to rising energy demand and evidence of the environmental effects of CO2 emissions, much research has focused on producing and storing energy from renewable sources. An efficient and selective process for the conversion of CO2 to CO or other reduced products could allow for the widespread production of liquid fuels. Coupled with renewable energy sources, these processes could help solve the large scale storage issue of renewable energies while creating a carbon neutral energy source easily integrated into the current energy infrastructure. To date, researchers have identified several bulk metal catalysts that are able to reduce CO2 electrochemically in aqueous electrolytes albeit requiring significant energy from an external source (i.e. overpotential) to drive the reaction. In particular, nanostructured catalysts are of great interest for CO2 to CO conversion due to their high catalytic surface area and unique properties relative to their polycrystalline counterparts. Here, we will present our recent work on a highly active nanostructured Zn electrocatalyst with the ability to reduce CO2 selectively towards CO with some of the best rates (i.e. currents) reported to date with dramatically reduced overpotential. We were able to develop an electrodeposited Zn catalyst with dendrite morphology able to selectively reduce CO2 at rates around an order of magnitude higher than bulk Zn with great long term stability. The higher surface area and defect sites formed in the electrochemical deposition of Zn show improved CO2 reduction activity and tolerance to the reaction conditions. Using in-situ x-ray absorption spectroscopy we are able to characterize the behavior of the Zn catalyst during CO2* electrolysis giving further insight into the oxidation state and coordination of the dendritic Zn catalyst.

Nanostructured Zn electrodes for electrochemical carbon dioxide reduction

249th National Meeting (2015)

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