Active and stable catalysts are essential for effective hydrogenation of gaseous CO2 into valuable chemicals. This work focuses on the structural and catalytic features of single metals, i.e., Co and Ni, as well as bimetallic CoNi alloy catalysts synthesized via combustion of reactive sol-gels. Different characterization methods were used for studying the relationships between the structure, composition, and catalytic activity of the fabricated materials. All catalysts exhibited highly porous sponge-like microstructure. The outermost surfaces of the CoNi alloys were more saturated with Co, while a stoichiometric Co/Ni ratio was observed for the particle’s bulk. Catalytic properties of the as-synthesized powders were studied in the CO2 hydrogenation reaction at 300 °C for over 80 h of time on stream. All the catalysts demonstrated exceptional selectivity with respect to CH4 formation. However, the combination of elemental Co and Ni in a single phase resulted in a synergistic effect in bulk alloy catalysts, with activity twofold to threefold that of single-metal catalysts. The activity and stability of the CoNi3 catalyst were higher than those previously reported for Ni-based catalysts. The reasons for this behavior are discussed.

The method of synthesis of a monophase boron phosphate (BPO4) powder has been refined. Single crystals of BPO4 free from solvent inclusions and cracks have been obtained by the top‐seeded solution growth technique with the seed orientation [010]. The growth is carried out under conditions of a low axial temperature gradient in the melt‐solution, which is varied in the range of 1–4°C cm−1. The value of the temperature gradient that promotes the growth of defective crystals is determined. The absorption spectra and optical homogeneity of crystals are studied. The chemical composition of polycrystalline BPO4 is studied using inductively coupled plasma mass spectrometry. The purity of the synthesized powder is better than 4 N.

We evaluated the temperature of 10% conversion (T10) of the CO oxidation reaction on the Co3O4/SiO2 catalyst as a tool for the rapid optimization of the catalyst synthesis through a simultaneously probabilistic and deterministic approach (SPADA) to the design of experiment (DOE). Multiparameter analysis (5 parameters on 4 levels) with simultaneous modification of several parameters was carried out to improve the solution combustion synthesis of the Co-based catalyst. We studied a four-component chemical system consisting of С2H5NO2 (glycine), Co (NO3)2⋅6H2O (cobalt nitrate), NH4NO3 (ammonium nitrate), and SiO2. A mathematical optimization model was built based on 16 experiments. The methodological aspects of the SPADA to the DOE were described and experimentally validated. The response of the T10 parameter was evaluated as a function of the active mixture composition, calcination parameters, and ratio between active phase and supporting material. Strong and weak parameters were identified, and the optimal synthesis conditions were predicted and experimentally verified.

In this study, metal-carbon nanocomposites have been synthesized via the method of simultaneous formation of bimetallic Fe–Co nanoparticles and carbon support based on pyrolyzed chitosan under the IR irradiation. The XRD structural characteristics as well as morphology and dispersity of Fe–Co nanoparticles depending on the loading of metals in the nanocomposites have been studied. It has been shown that the increase in the metal salts loading in the precursor leads to the formation of metal nanoparticles of larger size and more homogeneous composition of the Fe–Co solid solution. Detailed analysis of the XRD peaks of the obtained Fe–Co phase has allowed to distinguish them into several phases of a solid solution based on body-centered cubic and face-centered cubic lattices.