Lithium Vacancy-Tuned [CuO ] Sites for Selective CO Electroreduction to C Products.

Electrochemical CO reduction to valuable multi-carbon (C ) products is attractive but with poor selectivity and activity due to the low-efficient CC coupling. Herein, a lithium vacancy-tuned Li CuO with square-planar [CuO ] layers is developed via an electrochemical delithiation strategy. Density functional theory calculations reveal that the lithium vacancies (V ) lead to a shorter distance between adjacent [CuO ] layers and reduce the coordination number of Li around each Cu, featuring with a lower energy barrier for COCO coupling than pristine Li CuO without V . With the V percentage of ≈1.6%, the Li CuO catalyst exhibits a high Faradaic efficiency of 90.6 ± 7.6% for C at -0.85 V versus reversible hydrogen electrode without iR correction, and an outstanding partial current density of -706 ± 32 mA cm . This work suggests an attractive approach to create controllable alkali metal vacancy-tuned Cu catalytic sites toward C products in electrochemical CO reduction.