Improving CO₂-to-C₂₊ Product Electroreduction Efficiency <i>via</i> Atomic Lanthanide Dopant-Induced Tensile-Strained CuO<i>_x</i> Catalysts

Abstract

Cu is a promising electrocatalyst in CO₂ reduction reaction (CO₂RR) to high-value C₂₊ products. However, as important C-C coupling active sites, the Cu⁺ species is usually unstable under reduction conditions. How atomic dopants affect the performance of Cu-based catalysts is interesting to be studied. Herein, we first calculated the difference between the thermodynamic limiting potentials of CO₂RR and the hydrogen evolution reaction, as well as the *CO binding energy over Cu₂O doped with different metals, and the results indicated that doping atomic Gd into Cu₂O could improve the performance of the catalyst effectively. On the basis of the theoretical study, we designed Gd₁/CuO<i>_x</i> catalysts. The distinctive electronic structure and large ion radii of Gd not only keep the Cu⁺ species stable during the reaction but also induce tensile strain in Gd₁/CuO<i>_x</i>, resulting in excellent performance of the catalysts for electroreduction of CO₂ to C₂₊ products. The Faradic efficiency of C₂₊ products could reach 81.4% with a C₂₊ product partial current density of 444.3 mA cm^-2 at -0.8 V vs a reversible hydrogen electrode. Detailed experimental and theoretical studies revealed that Gd doping enhanced CO₂ activation on the catalyst, stabilized the key intermediate O*CCO, and reduced the energy barrier of the C-C coupling reaction.