Here we developed a new family of Zn-containing magnetic oxides of different structures by thermal decomposition of Zn(acac)2 in the reaction solution of preformed magnetite nanoparticles (NPs) stabilized by polyphenylquinoxaline. Upon an increase of the Zn(acac)2 loading from 0.15 to 0.40 mmol (vs 1 mmol of Fe(acac)3), the Zn content increases, and the Zn-containing magnetic oxide NPs preserve a spinel structure of magnetite and an initial, predominantly multicore NP morphology. X-ray photoelectron spectroscopy (XPS) of these samples revealed that the surface of iron oxide NPs is enriched with Zn, although Zn species were also found deep under the iron oxide NP surface. For all the samples, XPS also demonstrates the atom ratio of Fe(3+)/Fe(2+) = 2:1, perfectly matching Fe3O4, but not ZnFe2O4, where Fe(2+) ions are replaced with Zn(2+). The combination of XPS with other physicochemical methods allowed us to propose that ZnO forms an ultrathin amorphous layer on the surface of iron oxide NPs and also diffuses inside the magnetite crystals. At higher Zn(acac)2 loading, cubic ZnO nanocrystals coexist with magnetite NPs, indicating a homogeneous nucleation of the former. The catalytic testing in syngas conversion to methanol demonstrated outstanding catalytic properties of Zn-containing magnetic oxides, whose activities are dependent on the Zn loading. Repeat experiments carried out with the best catalyst after magnetic separation showed remarkable catalyst stability even after five consecutive catalytic runs.

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Lactose hydrogenation is a complex chemical process characterized by formation of numerous side products. Therefore, the synthesis of efficient catalysts for lactose hydrogenation and the investigation of the kinetics of this process are important for increasing of lactitol yield. Synthesis of nanocatalysts based on ruthenium-containing nanoparticles (NPs) formed in the pores of hypercrosslinked polystyrene (HPS) modified with amino groups and their catalytic properties in the lactose hydrogenation are described in the current work. The Ru species were incorporated in HPS using wet impregnation of ruthenium(IV) hydroxychloride followed by reduction with hydrogen at 300 °C. The catalysts containing from 1.1 wt % to 4.9 wt % of Ru were studied by X-ray fluorescence analysis, transmission electron microscopy, X-ray photoelectron spectroscopy, CO chemisorption, and liquid nitrogen physisorption methods. It was demonstrated that the NP sizes are controlled by the HPS pores. Several types of Ru species, Ru(IV), Ru(IV) × nH 2 O, Ru(0), and [RuO 4 ] 2− constituted the NP composition. The kinetics model developed is based on the concept of noncompetitive adsorption of hydrogen and organic molecules, because of the large difference in the sizes of sugar molecules and hydrogen, describing the experimental data well. The distribution and sensitivity of the parameters obtained were checked with the Markov−Chain Monte Carlo method.

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A new family of Ni-, Co-, and Cr-doped Zn-containing magnetic oxide nanoparticles (NPs) stabilized by polyphenylquinoxaline (PPQ) and hyperbranched pyridylphenylene polymer (PPP) has been developed. These NPs have been synthesized by thermal decomposition of Zn and doping metal acetylacetonates in the reaction solution of preformed magnetite NPs, resulting in single-crystal NPs with spinel structure. For the PPQ-capped NPs, it was demonstrated that all three types of metal species (Fe, Zn, and a doping metal) reside within the same NPs, the surface of which is enriched with Zn and a doping metal, while the deeper layers are enriched with Fe. The Cr-doped NPs at the high Cr loading are an exception due to favored deposition of Cr on magnetite located in the NP depth. The PPP-capped NPs exhibit similar morphology and crystallinity; however, the detailed study of the NP composition was barred due to the high PPP amount retained on the NP surface. The catalyst testing in syngas conversion to methanol demonstrated outstanding catalytic properties of doped Zn-containing magnetic oxides, whose activities are dependent on the doping metal content and on the stabilizing polymer. The PPP stabilization allows for better access to the catalytic species due to the open and rigid polymer architecture and most likely optimized distribution of doping species. Repeat experiments carried out after magnetic separation of catalysts from the reaction mixture showed excellent catalyst stability even after five consecutive catalytic runs.

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