Establishing Non-Stoichiometric TiO Assisted Asymmetrical C-C Coupling for Highly Energy-Efficient Electroreduction of Carbon Monoxide.

Exploring an appropriate support material for Cu-based electrocatalyst is conducive for stably producing multi-carbon chemicals from electroreduction of carbon monoxide. However, the insufficient metal-support adaptability and low conductivity of the support would hinder the C-C coupling capacity and energy efficiency. Herein, non-stoichiometric TiO was incorporated into Cu electrocatalysts (Cu-TiO), and served as a highly conductive and stable support for highly energy-efficient electrochemical conversion of CO. The abundant oxygen vacancies originated from ordered lattice defects in TiO facilitate the water dissociation and the CO adsorption to accelerate the hydrogenation to *COH. The highly adaptable metal-support interface of Cu-TiO enables a direct asymmetrical C-C coupling between *CO on Cu and *COH on TiO, which significantly lowers the reaction energy barrier for C products formation. Additionally, the excellent electroconductivity of TiO benefits the reaction charge transfer through robust Cu/TiO interface for minimizing the energy loss. Thus, the optimized 20Cu-TiO catalyst exhibits an impressive selectivity of 96.4 % and ultrahigh energy efficiency of 45.1 % for multi-carbon products, along with a remarkable partial current density of 432.6 mA cm. Our study underscores a novel C-C coupling strategy between Cu and the support material, advancing the development of Cu-supported catalysts for highly efficient electroreduction of carbon monoxide.