Surface Enrichment with Pd on the PdAg2 Nanoparticles for Selective Hydrogenation of 2-Methyl-3-butyn-2-ol in Microcapillary Reactor

Abstract This research aims to develop a PdAg/TiO2 catalytic film enriched with palladium on the surface of nanoparticles for selective semihydrogenation of 2-methyl-3-butyn-2-ol (MBY) in microcapillary reactor. Here we report an effective and versatile synthesis of colloidal core-PdAg/open shell-Pd NPs (PdAg4@Pd) by using a facile successive reduction method. Coating the core-PdAg4 with shell-Pd NPs enables a significant improvement in the activity of PdAg2/TiO2 (up to 24 times) for the selective semihydrogenation of a MBY. High-angle annular dark-field scanning transmission electron microscopy analysis reveal the presence of Ag atoms on Pd shell which is responsible for the suppression of MBY full hydrogenation by the Pd NPs. The as-fabricated on inner surface of microcapillary reactor film with PdAg4@Pd/TiO2 nanocomposites produces a 2-methyl-3-buten-2-ol (MBE) with selectivity 96 at 97% conversion and maintains good performance during 72 h. The proposed strategy can be used for the synthesis of an efficient single-atom alloy catalyst (SAAs) for selective hydrogenation of an alkynols in the pharmaceutical industry.