(378aa) Highly Selective Electroreduction of Carbon Dioxide into Fuels with High Current Density on Mesostructured Copper Oxide-Derived Inverse Opals

The production of environmentally-sustainable chemicals and fuels from CO₂ by highly efficient, selective, Earth-abundant, robust electrocatalytic materials is of vital interest not only to attenuate the climate change but also to find alternative ways to maintain carbon resources. In this work, we focus on well-defined mesostructured CuO-derived inverse opal (CuO-IO) electrode which has demonstrated remarkably high CO selectivity and negligible H₂ evolution at modest overpotentials compared to typical CuO materials. The cycle voltammetry reveals the reversible Cu⁰ ↔ Cu⁺ ↔ Cu²⁺ redox waves which is consistent with morphological and oxidation changes in CuO-IO before and after reaction observed by HR-TEM, SEM, XPS, and Raman tools. High current densities at different constant potentials are very stable for an extended period of time, reaching -10 and -27 mA cm^-2 at -0.8 and -1.1 V vs. RHE. Such a porous network with voids about 200 nm in diameter surprisingly exhibits a Faradaic efficiency (FE) for CO production of 72% at -0.6 V vs. RHE, implying the advantage of highly ordered, interconnected mesopores in a hexagonal close packed structure in favorable production of CO and other C1-C2 products.