Effect of the conditions of thermal reduction on the formation, stability, and catalytic properties of polymer-stabilized palladium nanoparticles in the selective hydrogenation of acetylene alcohols

Abstract

This work is dedicated to studying the thermal degradation of palladium acetate in commercial MN270 hypercrosslinked polystyrene in the temperature range of 200 to 325°C by means of TGA and XPS. It is shown that palladium acetate distributed in hypercrosslinked polystyrene is destroyed with the formation of palladium metal at lower temperatures than the pure salt powder. It is established that the formation and stabilization of Pd 7 -Pd 10 palladium clusters and their partial aggregation with the formation of palladium nanoparticles occur in the course of destruction. Catalytic testing of the resulting systems in selective triple bond hydrogenation in dimethylethynylcarbinol in a toluene solution at 90°C reveals their considerable supe riority in activity and selectivity over commercial Lindlar catalyst: a more than twofold increase in TOF at 97.8% selectivity.

Mono- and Bimetallic Nanoparticles Stabilized by an Aromatic Polymeric Network for a Suzuki Cross-Coupling Reaction

“…It was shown that independently in the presence of a second metal, palladium acetate is uniformly distributed in a highly porous aromatic network of HPS, which allows formation of small Pd NPs of about 2 nm in diameter after reduction in a hydrogen flow at 300 °C (the limit of temperature stability of the chosen HPS [ 40 ]). In the case of the Pd(CH 3 COO) 2 precursor, such reduction conditions are suitable for fast growth of metallic NPs [ 41 ]. However, for other metal acetates used in this work, such as Cu(CH 3 COO) 2 and Zn(CH 3 COO) 2 , reduction was not achieved, and the corresponding oxides were found on the surface of bimetallic catalysts.…”