Selective CO₂ electroreduction to C₂H₄ on porous Cu films synthesized by sacrificial support method

A series of copper-based electrocatalysts were prepared by the Sacrificial Support Method (SSM) with variation of synthesis parameters. Thin films of the materials were evaluated for their electrocatalytic activities towards CO₂ electroreduction to short-chain (C₁-C₂) hydrocarbons by standard electrochemical methods. Gas-phase reaction products were quantified using an online gas chromatography system. At -0.98 V vs reversible hydrogen electrode (RHE), copper oxide-derived catalysts were found to have selectivity toward C₂H₄ approximately one order of magnitude higher than to CH₄. The highest selectivity towards C₂H₄ production at -0.98 V was demonstrated by the catalyst with cube morphology, synthesized with 20 wt% Cu: 80 wt% SiO₂ ratio in the precursor. Possible causes for this shift in selectivity are discussed in terms of the morphology and surface/core composition as determined by scanning electron microscopy (SEM), X-Ray diffraction (XRD), and X-Ray photoelectron spectroscopy (XPS).