Unravelling in-situformation of highly active mixed metal oxide CuInO2nanoparticles during CO2electroreduction

Technologies and catalysts for converting carbon dioxide (CO2) to immobile products are of high interest to minimize greenhouse effects. Copper(I) is a promising catalytic active state of copper but hampered by the inherent instability in comparison to copper(II) or copper(0). Here, we report a stabilization of the catalytic active state of copper(I) by the formation of a mixed metal oxide CuInO2nanoparticle during the CO2electroreduction. Our result shows the incorporation of nanoporous Sn:In2O3interlayer to Cu2O pre-catalyst system lead to the formation of CuInO2nanoparticles with remarkably higher activity for CO2electroreduction at lower overpotential in comparison to the conventional Cu nanoparticles derived from sole Cu2O. OperandoRaman spectroelectrochemistry is employed to in-situmonitor the process of nanoparticles formation during the electrocatalytic process. The experimental data are collaborated with DFT calculations to provide insight into the electro-formation of the type of Cu-based mixed metal oxide catalyst during the CO2electroreduction, where a formation mechanism viacopper ion diffusion across the substrate is suggested.