Synthesis of catalytic systems based on nanocomposites containing palladium and hydroxycarbonates of rare-earth elements

Abstract

The preparation, characterization, and catalytic activity of nanocomposites containing palladium nanoparticles supported on yttrium and cerium hydroxycarbonates in the Suzuki cross-coupling reaction between phenylboronic acid and iodobenzene are described. All catalytic systems were characterized by means of SEM, EDS, and their surface areas were determined with N2 physisorption. The conversion degree of the Suzuki reaction was characterized with gas chromatography, and the reaction products were identified with 1H and 13C{1H}–NMR spectra. Nanocomposites Pd/Y(OH)CO3 and Pd/Ce(OH)CO3 were synthesized according to two methods: the first one—simultaneous production of nanoscale substrate and immobilization of palladium nanoparticles on its surface (nanocomposites 1), the second one—the prior synthesis of polyvinylpyrrolidone stabilized palladium nanoparticles followed by their immobilization on the nano-sized substrate surface (nanocomposites 2). Both groups of catalysts showed high catalytic activity with the highest TOF values 8.5 × 103 h–1 for nanocomposites 1 and 78.9 × 103 h–1 for nanocomposites 2 allowing to decrease the palladium content in the nanocomposites and, consequently, reduce the cost of the catalyst while maintaining its high catalytic activity.