Lithium Vacancy-Tuned [CuO4] Sites for Selective CO2 Electroreduction to C2+ Products

Electrochemical CO2 reduction to valuable multi-carbon (C2+) products is attractive but with poor selectivity and activity due to the low-efficient C-C coupling. Herein, a lithium vacancy-tuned Li2CuO2 with square-planar [CuO4] layers is developed via an electrochemical delithiation strategy. Density functional theory calculations reveal that the lithium vacancies (V-Li) lead to a shorter distance between adjacent [CuO4] layers and reduce the coordination number of Li+ around each Cu, featuring with a lower energy barrier for CO-CO coupling than pristine Li2CuO2 without V-Li. With the V-Li percentage of approximate to 1.6%, the Li2-xCuO2 catalyst exhibits a high Faradaic efficiency of 90.6 +/- 7.6% for C2+ at -0.85 V versus reversible hydrogen electrode without iR correction, and an outstanding partial current density of -706 +/- 32 mA cm(-2). This work suggests an attractive approach to create controllable alkali metal vacancy-tuned Cu catalytic sites toward C2+ products in electrochemical CO2 reduction.

Automated summary

Utilizing an electrochemical delithiation strategy, a lithium vacancy-tuned Li2CuO2 catalyst was developed to enhance the efficiency and selectivity of electrochemical CO2 reduction to valuable multi-carbon (C2+) products. The introduction of lithium vacancies led to improved CO-CO coupling, resulting in a high Faradaic efficiency of 90.6 +/- 7.6% for C2+ and an outstanding partial current density of -706 +/- 32 mA cm(-2) under certain conditions. This work demonstrates a promising approach to produce controllable alkali metal vacancy-tuned Cu catalytic sites for C2+ products in electrochemical CO2 reduction.