Improving CO 2 -to-C 2+ Product Electroreduction Efficiency via Atomic Lanthanide Dopant-Induced Tensile-Strained CuO x Catalysts

Cu is a promising electrocatalyst in CO 2 reduction reaction (CO 2 RR) to high-value C 2+ 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 CO 2 RR and the hydrogen evolution reaction, as well as the *CO binding energy over Cu 2 O doped with different metals, and the results indicated that doping atomic Gd into Cu 2 O could improve the performance of the catalyst effectively. On the basis of the theoretical study, we designed Gd 1 /CuO x 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 Gd 1 /CuO x, resulting in excellent performance of the catalysts for electroreduction of CO 2 to C 2+ products. The Faradic efficiency of C 2+ products could reach 81.4% with a C 2+ 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 CO 2 activation on the catalyst, stabilized the key intermediate O*CCO, and reduced the energy barrier of the C–C coupling reaction.