Electrochemical reduction of carbon dioxide (CO2) to liquid fuels is an effective approach to store intermittent renewable electricity and diminish our reliance on fossil fuels. Ethanol is an attractive product as it is energy dense and can easily leverage existing distribution infrastructure. The conversion of CO2 to ethanol involves multiple electron-proton concerted steps that form many reaction intermediates. Here, we introduce the use of complementary tactics that form desirable reaction intermediates while displacing those that favor competing reactions. In the first step, we coat silver onto a copper-based gas diffusion electrode to destabilize the formation of reaction intermediates such as HCCOH and CCH that favor ethylene production. We then functionalize the electrode with a cobalt-based phthalocyanine that promotes high local concentrations of carbon monoxide (CO), a key intermediate in the formation of ethanol. Finally, we introduce the electrode into a novel three-chamber flow cell design that employs an highly conductive cation exchange resin to actively remove ethanol from the electrode surface and encourage the formation of favorable reaction intermediates. To complement this work, we use a suite of material characterization tools including Fourier transform infrared spectroscopy (FTIR), in-situ Raman spectroscopy, and BET. With this new copper-based electrode and flow cell design we expect to achieve record setting conversion efficiencies and ethanol titers.

Electrons to fuels: Accelerated electrochemical carbon dioxide to ethanol conversion via targeted influence of local reaction intermediates in a three-chamber flow cell

ACS Fall 2020 Virtual Meeting

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