Ultrafine PdZn bimetallic nanoparticles anchored on sulfur-doped mesoporous carbon for the partial hydrogenation of alkynols

Abstract

The catalytic partial hydrogenation of alkynols is a key approach for the synthesis of enols, which are crucial chemical intermediates for pharmaceuticals and essences. Low selectivity is the main challenge of the partial hydrogenation of alkynols due to the easy over-hydrogenation of alkynyl groups. Herein, ultrafine PdZn bimetallic nanoparticles (NPs) were anchored on a S-doped mesoporous carbon catalyst (PdZn/Meso_S-C) and used for the partial hydrogenation of alkynols. Zn metal with a high electron density was used to modify the active metal Pd to change the electronic and geometric configuration of the Pd active sites, which improve the selectivity of enols during the partial hydrogenation of alkynols. Furthermore, the use of a S-doped mesoporous carbon support dispersed and stabilized the ultrafine PdZn NPs due to strong interactions between the metal atoms and S sites. This also prevented PdZn ultrafine NPs from aggregating and increased the partial hydrogenation selectivity. The partial hydrogenation of propynol ethoxylate (PME) catalyzed by PdZn/Meso_S-C reached 96.0% enol selectivity, while the alkynol conversion reached 97.5%. The general applicability of PdZn/Meso_S-C for the partial hydrogenation of various alkynols has also been demonstrated. Thus, this work has great application prospects for the high-efficiency catalytic partial hydrogenation of alkynols.