Propylene is an important raw material for the production of many valuable compounds, especially polypropylene, the consumption of which continues to grow every year. The reaction of oxidative dehydrogenation of propane, where carbon dioxide is used as a mild oxidant, is a promising method for producing propylene. At the same time, the problem of utilization of greenhouse gas CO₂ is partially solved. The synthesis and analysis of the physicochemical properties of mesoporous silicate MCM-41 and supported catalysts CrO_x/MCM-41 prepared on its basis were carried out. These catalysts were prepared using incipient wetness impregnation. The support and catalysts were characterized by the methods of low-temperature nitrogen adsorption, TG-DTA, XRD, SEM, TPR-H₂, UV/Vis diffuse reflectance spectroscopy, and small-angle X-ray scattering. It is shown that chromium is present in the samples simultaneously in the form of Cr³⁺ and Cr⁶⁺. The catalytic tests were performed in the range of 550–700 °C. The highest selectivity for propylene was observed for the 5%Cr/MCM-41 catalyst and was 76% at a temperature of 650 °C with a propane conversion of 20%. The deposited catalysts Cr/MCM-41 and Cr/SiO₂ (Acros) were compared. The propylene selectivity for the MCM-41-supported catalyst was ~1.5 times higher than that for the SiO₂-supported catalyst.

An analysis is performed of the physicochemical properties of M/SiO₂ (M = Fe, Co, and Ni) oxide monometallic and CrM/SiO₂ (M = Fe, Co, and Ni) bimetallic catalysts supported on amorphous silica. The catalysts are characterized via TGA, XRD, UV–Vis diffuse reflectance spectroscopy, and SEM. Adding 1 wt % of a second transition metal (Fe, Ni, and Co) to the 3% CrO_x/SiO₂ chromium oxide catalyst substantially raises the conversion of propane to 64% with a drop in the selectivity towards propylene and formation of methane as a main by-product in the case of nickel. Introducing iron and cobalt raises the selectivity towards propylene to 72% with a drop in the conversion of propane.

In this work, hydrolysis lignin with nickel compounds deposited on the surface was prepared. The resulting material was introduced into the process of carbon dioxide assisted conversion and the catalytic activity of the deposited nickel compounds in this reaction was evaluated. Use of the obtained catalytic system increases CO₂ conversion by more than 30% in the temperature range 450–800 °C. After the conversion process, the material was subjected to a study using a variety of physico-chemical analysis methods (TEM, SEM-EDX, and X-ray phase analysis). Physico-chemical methods of analysis of a sample calcined at 300 °C to decompose nickel nitrate revealed NiO nanoparticles with an average particle size of 16.9 nm.

A series of 5 wt.% Cr/SiO₂ catalysts were prepared through incipient wet impregnation using different chromium salts as a source of Cr (chromium (III) sulfate, acetylacetonate, nitrate, ammonium dichromate). The obtained catalysts were characterized by SEM-EDX, TEM, DRIFT-CD₃CN spectroscopy, UV-VIS diffuse reflectance spectroscopy, and the N₂ low-temperature adsorption–desorption technique. The catalysts were tested in propane, and isobutane dehydrogenation assisted with CO₂ at 600–750 °C. The highest activity in propane dehydrogenation was observed for the catalyst obtained from chromium acetylacetonate, the yield of propylene was 32% at 750 °C, and in the isobutane dehydrogenation reaction, the catalyst obtained from chromium sulfate was the best one; the yield of isobutene was ~30% at 600 °C. The obtained results show that the type of chromium precursor has a significant effect on the efficiency of the catalyst in the propane and isobutane dehydrogenation with CO₂.

While the attempts to find new energy sources have intensified, the interest in the use of biomass as a carbon-rich raw material still is increasing. In this work, we studied iron-, cobalt-, and nickel-based materials in the process of CO₂-assisted gasification of sunflower husk. The materials with and without metal additives were examined by XRD, SEM, EDX, and TEM techniques and were tested in their gasification under the action of CO₂. It was found that the Co-based material demonstrates the best activity among the studied ones (the CO₂ conversion was up to 83%). The possible reason for such superiority may be related to the capability of Ni compounds to the formation of the metallic nickel phase and insufficient activity of iron species.