A Cu2B2 monolayer with planar hypercoordinate motifs: an efficient catalyst for CO electroreduction to ethanol

Sustainable production of high-value carbon-based fuels and chemicals through electrochemical CO reduction (COR) under mild conditions is a promising alternative to the traditional Fischer-Tropsch process that requires high energy input and large-scale reactors. However, the COR process suffers from the low activity and poor selectivity of the currently employed electrocatalysts, greatly hampering its large-scale application. Herein, by means of comprehensive swarm-intelligence structure search and first-principles computations, we identify an ideal electrocatalyst for COR, i.e., a metallic Cu2B2 monolayer with planar heptacoordinate copper and planar pentacoordinate boron. Our results reveal that the predicted Cu2B2 monolayer exhibits superior thermal and dynamic stability and holds promise for experimental realization. More importantly, this catalyst could effectively reduce CO to ethanol through the carbene mechanism with a low limiting potential (-0.59 V) and a small barrier for C-C coupling (0.41 eV). Our work is the first report on the as-designed electrocatalyst with planar hypercoordinate motifs for CO reduction to C-2 products, which not only widens the potential application of hypercoordinate 2D materials, but also opens up a new and promising avenue for converting abundant industrial CO to value-added ethanol.