Mesoporous Cu₂O microspheres for highly efficient C₂ chemicals production from CO₂ electroreduction

Production of C₂ chemicals (such as C₂H₄, C₂H₅OH, etc.) from CO₂ electroreduction reaction (CO₂ER) has been regarded as a promising route to solve the environmental problems and energy crisis. In this work, mesoporous Cu₂O microspheres of ca. 700 nm diameter size with low crystallinity were fabricated to enable efficient conversion of CO₂ to C₂ chemicals by electrocatalytic reduction. It is revealed that compared with bulk Cu₂O, the obtained mesoporous Cu₂O microspheres have larger surface area, more grain boundaries and defects (unsaturated coordination sites), which facilitate the adsorption and stabilization of the important intermediates, such as *CO, on the route to C₂ chemicals formation. As a result, the Faraday efficiency (FE) of C₂ products reaches as high as 82.6 % and 78.5 % in an H-cell and a flow cell, respectively. In situ Raman and FT-IR spectra reveal that during CO₂ER test there exists abundant *CO on the mesoporous Cu₂O surface, thus increasing the opportunity of CC coupling. And the high coverage of *CO on catalyst surface during CO₂ER protects and stabilizes the oxidation state of Cu species. This work demonstrates an effective strategy to introduce mesoporous structures and decreased crystallinity for improving the performance of CO₂ER to C₂ products.