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Palladium catalysts were obtained by the adsorption method involving the sequential deposition of polyvinylpyrrolidone (PVP) and then palladium ions on a modified zinc oxide surface without high-temperature calcination and reduction stages. The immobilized PVP-palladium catalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET), infrared spectroscopy (IRS), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and elemental analysis methods. It was found that the introduction of polymer into the catalyst’s composition promotes the dispersion and uniform distribution of active phase nanoparticles (PdO, Pd0) on the surface of zinc oxide. The catalysts were tested in the hydrogenation of complex acetylene alcohol, 3,7,11-trimethyldodecyn-1-ol-3 (C15-yn) under mild conditions (0.1 MPa, 40 °C). For comparison, studies on stereoselective hydrogenation of the short-chain alcohol 2-hexynol-1 were performed. It was shown that modification of the catalyst with polymer improves its catalytic properties. High C15-alkenol selectivity (98%), activity (W = 70 × 10−6 mol/s), and stability (turnover number (TON) 62,000) were achieved on a Pd-PVP/ZnO catalyst. Varying the active phase made it possible to reduce the metal content without deteriorating the catalytic performance of the catalyst.

A simple and environmentally friendly method, based on sequential adsorption of polyacrylamide (PAM) and transition metal ions (Pd 2+ , Ag + ) on zinc oxide precipitated from water solution, was used to synthesize supported mono-and bimetallic catalysts with various Pd:Ag ratios. The catalyst characterization results indicated that PAM and metal ions are completely adsorbed by zinc oxide, forming polymer-stabilized Pd and Ag nanoparticles of 1-3 nm in size, evenly distributed on the support surface. The catalysts were studied in the hydrogenation of phenylacetylene under mild conditions (0.1 MPa, 40°C). Although Ag-free 1%Pd-PAM/ZnO catalyst presents an interesting catalytic performance (in terms of activity and selectivity), the optimal catalyst was 1%Pd-Ag(3:1)-PAM/ZnO, presenting a selectivity to styrene of 88% at 85.4% conversion of phenylacetylene. For comparison, similar Pd-Ag (3:1) bimetallic catalysts modified with polysaccharides such as pectin (Pec), chitosan (Chit) and 2-hydroxyethylcellulose (HEC) were studied in the hydrogenation process. The catalysts demonstrated nearly the same selectivity to styrene. The activity of the catalysts decreases in the following order: 1%Pd-Ag(3:1)-HEC/ZnO > 1%Pd-Ag(3:1)-PAM/ZnO > 1%Pd-Ag(3:1)-Pec/ZnO > 1%Pd-Ag(3:1)-Chit/ZnO.

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