Switching Products Selectivity in Electrocatalytic C(sp ³ )─H Bonds Activation and CO ₂ Carboxylation via Cu─S Bond Crystal Engineering

Abstract Inert C(sp 3 )─H bonds activation along with CO 2 carboxylation to prepare high‐value carboxylic acids is a sustainable route for achieving the carbon‐neutral goal, but the current catalytic performance is far from satisfying the demand. Targeting this problem, it was found that crystal engineering of Cu─S bonds not only significantly enhanced the activity of C(sp 3 )─H activation and CO 2 carboxylation in an electrocatalytic system, but also efficiently realized chemoselectivity in the CO 2 carboxylation process. Specifically, hexagonal CuS(001) electrocatalyst could readily achieve C(sp 3 )─H bond activation of alkanes and aromatics along with CO 2 carboxylation, exhibiting almost complete chemoselectivity to carbon chain increased monocarboxylation acids. Intriguingly, hexagonal Cu 2 S(110) electrocatalyst, which was prepared by phase transition, could realize highly selective alkanes and aromatics dicarboxylation with CO 2 to produce dicarboxylation acids. Notably, biomass compound 2‐methylfuran was efficiently converted into furan‐2‐acetic acid over CuS(001); while 2,5‐dimethylfuran was quantitatively converted to the degradable polymer precursor furan‐2,5‐dicarboxylic acid over Cu 2 S(110). Moreover, density functional theory (DFT) results revealed the origin of differences in the activity and chemoselectivity over CuS(001) and Cu 2 S(110) catalysts.