Polyacetylene-Decorated Pt/TiO₂ Catalyst for Highly Selective Hydrogenation of Alkynes

Supported Pt nanoparticles (NPs) and Pt single atoms (SAs) are widely employed in the selective hydrogenation of various fine chemicals, where Pt NPs typically deliver high activity while Pt SAs afford exceptional selectivity. Integrating these advantages into a unified catalytic system to reconcile the trade-off between activity and selectivity in alkynes hydrogenation remains a formidable challenge. Herein, a novel Pt/TiO₂-200C₂H₂ catalyst featuring both Pt NPs and Pt SAs active sites was prepared via a simple and mild C₂H₂ pretreatment. The C₂H₂ monomer undergoes polymerization to form trans-polyacetylene (PA), which in situ covers the surface of Pt NPs and Pt SAs. The PA coating on the Pt/TiO₂-200C₂H₂ surface donates electrons to Pt sites, promoting H₂ dissociation and activation, inhibiting sintering and aggregation of the Pt species, thereby significantly enhancing the catalytic activity and stability toward the hydrogenation of various alkynes. Density functional theory (DFT) calculations prove that the PA coating increases the hydrogenation barrier of styrene on both Pt NPs and Pt SAs, suppressing over-hydrogenation and enhancing selectivity. This work not only offers a novel approach for fabrication of Pt-based dual active site catalysts but also presents a scalable polymer coating for modulating the catalytic performance of alkynes hydrogenation catalysts.