Top‐down construction of a Cu‐Bi/<scp>CaCO₃</scp> bifunctional catalyst from bulk precursors for alkyne–aldehyde coupling reaction

Abstract 1,4‐Butanediol (BDO), a critical precursor for biodegradable plastics, is industrially synthesized via the Reppe process using CuBi catalysts, which suffer from low alkyne–aldehyde coupling activity and rapid deactivation. This study developed a CuBi/CaCO 3 bifunctional catalyst via a novel top‐down solid‐state redispersion strategy. The CaCO 3 support could enhance formaldehyde activation and promote the surface alkyne–aldehyde coupling reaction at Cu‐Bi active sites. The optimized CuBi‐CaCO 3 ‐10% catalyst achieved a four‐fold higher butynediol yield than commercial counterparts during 40‐h continuous operation and retained high activity after three cycles, whereas the commercial catalyst (CuBi commercial catalyst) deactivated completely. Kinetic and in situ Fourier transform infrared analyses revealed stability mechanisms: (i) CaCO 3 ‐mediated aldehyde activation accelerates the main reaction pathway while suppressing side reactions. (ii) Strong Cu‐Bi/CaCO 3 metal‐support interactions stabilize Cu + species. This work provides a high‐performance catalytic strategy for industrial BDO production, emphasizing the synergy between tailored metal‐support interfaces and optimized reaction dynamics.