Oxygen‐vacancy‐driven Cu‐Bi catalyst for highly efficient formaldehyde ethynylation toward 1,4‐butynediol

The synthesis of 1,4‐butynediol via formaldehyde ethynylation is a process of considerable industrial importance. Herein, Cu‐Bi catalysts were synthesized via a co‐precipitation method. The optimized Cu‐Bi catalyst with 10 wt% Bi loading (denoted as CuO/10Bi 2 O 3 ) delivered outstanding performance, providing a 1,4‐butynediol yield of 74% at 94% selectivity. Remarkably, it maintained a 60% yield with 94% selectivity after 100 h of continuous operation, demonstrating stability on par with that of the commercial RK catalyst. Kinetic studies determined an activation energy of only 28.64 kJ/mol for CuO/10Bi 2 O 3 , significantly lower than the 64.88 kJ/mol measured for the RK catalyst. Furthermore, combined structural characterizations, density functional theory calculations, and Bader charge analyses reveal that the Cu‐Bi electronic synergy and abundant oxygen vacancies in CuO/10Bi 2 O 3 stabilize Cu + sites, suppress their over‐reduction, and further stabilize the Cu 2 C 2 active center, ultimately endowing the catalyst with high activity and long lifetime.