The utilization of carbon dioxide is a major
incentive for the growing field of carbon capture. Carbon dioxide could be an
abundant building block to generate higher value products. Herein, we describe
the use of porous copper electrodes to catalyze the reduction of carbon dioxide
into higher value products such as ethylene, ethanol and, notably, propanol.
For <i>n</i>-propanol production, faradaic
efficiencies reach 4.93% at -0.83 V <i>vs</i>
RHE, with a geometric partial current density of -1.85 mA/cm<sup>2</sup>. We
have documented the performance of the catalyst in both pristine and
urea-modified foams pre- and post-electrolysis. Before electrolysis, the copper
electrode consisted of a mixture of cuboctahedra and dendrites. After 35-minute
electrolysis, the cuboctahedra and dendrites have undergone structural
rearrangement. Changes in the interaction of urea with the catalyst surface
have also been observed. These transformations were characterized <i>ex-situ</i> using scanning electron
microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. We found
that alterations in the morphology, crystallinity, and surface composition of
the catalyst led to the deactivation of the copper foams.
Competition between Hydrogen Evolution and Carbon Dioxide Reduction on Copper Electrodes in Mildly Acidic Media