Morphology‐Directed Selective Production of Ethylene or Ethane from CO2 on a Cu Mesopore Electrode

The electrocatalytic conversion of CO2 to value‐added hydrocarbons is receiving significant attention as a promising way to close the broken carbon‐cycle. While most metal catalysts produce C1 species, such as carbon monoxide and formate, the production of various hydrocarbons and alcohols comprising more than two carbons has been achieved using copper (Cu)‐based catalysts only. Methods for producing specific C2 reduction outcomes with high selectivity, however, are not available thus far. Herein, the morphological effect of a Cu mesopore electrode on the selective production of C2 products, ethylene or ethane, is presented. Cu mesopore electrodes with precisely controlled pore widths and depths were prepared by using a thermal deposition process on anodized aluminum oxide. With this simple synthesis method, we demonstrated that C2 chemical selectivity can be tuned by systematically altering the morphology. Supported by computational simulations, we proved that nanomorphology can change the local pH and, additionally, retention time of key intermediates by confining the chemicals inside the pores. I pity the pore intermediate: Nanomorphology‐directed C2‐product selectivity was demonstrated on a Cu mesopore electrode. A local flow field is generated on the electrode surface and confines reaction intermediates inside the pore. The prolonged retention time of the intermediates affects the kinetics of protonation and C−C bond formation, determining the final C2 product.