The development of new catalytic systems based on cobalt and iron compounds for the production of oxygen-containing compounds is an urgent task of chemical technology. The purpose of this work is the synthesis of CoFe₂O₄ stabilized with polyvinylpyrrolidone (PVP), the study of the catalyst by physico-chemical research methods, and the determination of the effectiveness of the CoFe₂O₄/PVP catalyst in the phenol oxidation reaction. In this work, magnetic composites CoFe₂O₄ and CoFe₂O₄ stabilized with polyvinylpyrrolidone were synthesized by co-deposition. A comparison of the characteristics of the properties of the synthesized cobalt (II) ferrite (CoFe₂O₄) and the composite material CoFe₂O₄/PVP based on it is carried out. The obtained samples were examined using X-ray phase analysis (XRD), the Debye–Scherrer method, scanning electron microscopy (SEM), Mossbauer and IR Fourier spectroscopy, as well as thermogravimetric analysis (TGA). The textural properties were determined based on the analysis of nitrogen isotherms. The catalytic properties of the synthesized materials in the process of phenol oxidation in the presence of hydrogen peroxide are considered. The analysis of the reaction mixtures by HPLC obtained by the oxidation of phenol in the presence of a CoFe₂O₄/PVP catalyst showed a decrease in the concentration of phenol in the first 15 min of the process (by 55–60%), and then within 30 min, the concentration of phenol decreased to 21.83%. After 2 h of the process, the conversion of phenol was already more than 95%. The final sample after the reaction contained 28% hydroquinone and 50% benzoquinone. It was found that the synthesized magnetic composites exhibit catalytic activity in this process.

It is known that highly efficient catalysts for the catalytic oxidation of aromatic hydrocarbons can be obtained based on magnetic nanoparticles. The development of nanosized magnetically controlled catalysts for the oxidation of aromatic hydrocarbons with oxygen deserves especially close attention in the territory of the Republic of Kazakhstan, which does not have its own industrial production of oxygen-containing compounds. The aim of this work is to create catalysts based on Fe and Co nanoparticles stabilized with polymers: polyvinylpyrrolidone, chitosan, and polyethylenimine, study them by methods of physico-chemical research, and conduct preliminary tests of catalysts to predict their effectiveness. Magnetic nanoparticles were prepared by the co-precipitation method. Based on the results of the SEM analysis, it was concluded that polymers form composites together with metal nanocrystals. According to preliminary data, the most efficient oxidation of phenol in a non-flowing glass gradient-free thermostated duck-type reactor occurs on Fe₃O₄/chitosan, with the phenol conversion being 55–60%. Tests on the oxidation of phenol with oxygen showed a favorable prognosis for the use of such catalysts for the oxidative conversion of aromatic hydrocarbons in order to obtain valuable intermediates.

The development of technologies for processing oil residues is relevant and promising for Kazakhstan, since the main oil reserves of hydrocarbons in the country are in heavy oils. This paper describes the study of the influence of technological modes on the yield and hydrocarbon composition of products formed because of cracking of commercial fuel oil and fuel oil M-100 in the presence of air in the reactor. For catalysts preparation, natural Taizhuzgen zeolite and Narynkol clay were used. It was found that the introduction of air into the reaction zone, in which oxygen is the initiator of the cracking process, significantly increases the yield of the middle distillate fractions. In the presence of air, the yield of diene and cyclodiene hydrocarbons significantly increases compared to cracking in an inert atmosphere. According to the data of IR spectral analysis of M-100 grade oil fractions, in addition to normal alkanes, the final sample contains a significant amount of olefinic and aromatic hydrocarbons. On the optimal catalyst, owing to oxidative cracking of fuel oil, the following product compositions (in %) were established: Fuel oil M-100: gas – 0.8, gasoline – 1.1, light gas oil – 85.7, heavy residue – 11.9, loss – 0.5 and total – 100.0%; commodity Fuel oil (M-100): gas – 3.3, gasoline – 8.4, light gas oil – 84.3, heavy residue – 4.0, loss – 0 and total – 100.0%.

Iron-based catalysts for direct CO₂ hydrogenation to hydrocarbons (CO₂-FTS) have attracted rapidly growing research interest as a Power-to-X route, yet we did not identify a prior systematic review with descriptive quantitative synthesis focused specifically on this catalyst class. To the best of the authors’ knowledge, this work provides a systematic descriptive quantitative synthesis, covering 60 coded reports published between January 2017 and July 2026 and identified by structured searches of Scopus, Web of Science Core Collection, and ScienceDirect. After PRISMA-adapted eligibility reconciliation, 49 primary studies were included; 42 reported extractable numerical CO₂ conversion data and contributed to the descriptive quantitative synthesis, while seven were retained for qualitative analysis only. Median CO₂ conversion across the 42 quantitative studies was 38.3% (range 8.5–69.9%; SD = 15.3%), providing a dataset-specific reference for the reviewed literature. Across the predefined subgroups, mean CO₂ conversion varied from 31.6% to 47.1%, with substantial differences in operating conditions and small subgroup sizes limiting direct attribution to catalyst composition. The highest absolute conversion, 69.9%, was achieved by two-stage reactor engineering with interstage H₂O removal, not catalyst reformulation, identifying product-water inhibition as an important single-stage conversion constraint. The highest recorded product selectivities across the dataset were 64.3% to C₅⁺ (Na-FeMgMnOx), 82.6% to light olefins (Y₂O₃/Fe–Co/SAPO-34), and 75.6% to aromatics (ZnFeOx-Na/HZSM-5); maximum demonstrated stability was 205 h (3K/6Cu-Fe₂O₃/C nanosheets). Analysis of the full conversion–selectivity dataset reveals that only approximately 14% of studied systems simultaneously exceeded the conversion median and a 44% target-selectivity threshold. The synthesis further identifies that key physicochemical descriptors (BET surface area, post-reaction Mössbauer phase composition, CO₂-TPD basicity, ASF α, space-time yield normalised to iron mass, and stability data) are absent from 60–85% of primary reports, and proposes recommended reporting elements to facilitate future quantitative synthesis. Because study-level variances and standardised controls were unavailable, no weighted effect-size meta-analysis was performed; the results should be interpreted as a descriptive quantitative synthesis. The review was not prospectively registered.

The catalytic conversion of carbon dioxide (CO2), generated in large quantities at oil and gas production facilities and gas processing plants, into high-value hydrocarbons is regarded as a promising pathway for the development of low-carbon petrochemical technologies. Particular attention has been devoted to iron-based catalysts capable of hydrogenating CO2 into olefins, alcohols, and other C2+ products that can serve as valuable feedstocks for petrochemical applications. This review summarizes recent advances in the understanding of the structural evolution of iron-based catalysts under CO2 hydrogenation conditions. The effects of catalyst composition, promoters, textural characteristics, activation procedures, and reaction conditions on the formation of active phases, the carburization of iron oxides, and the selectivity toward C2+ products are systematically analyzed. In addition, the mechanisms of phase transformations between iron oxides and iron carbides, as well as their roles in the formation of olefins and oxygenated compounds, are discussed. The analysis provides deeper insight into the relationship between the structure of ironbased catalysts and product selectivity. The findings may serve as a practical foundation for the development of efficient catalysts and the optimization of CO2 conversion processes aimed at producing valuable feedstocks for the petrochemical and gas-processing industries.

This study presents the development of magnetic composite nanosorbents based on iron oxide and humic acids (HA) for the removal of heavy metal ions from aqueous media. The nanocomposites were synthesized by chemical co-precipitation followed by surface modification with humic acids in a vortex electromagnetic field. The phase composition, structure, morphology, and physicochemical properties of the synthesized materials were investigated using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and magnetometry. The sorption properties of the obtained materials were assessed using atomic absorption spectrometry based on the degree of extraction of heavy metal ions from model aqueous solutions. It was established that modification of the iron oxide surface with humic acids promotes the formation of a functionalized surface capable of interacting with metal ions. The combination of sorption sites provided by the humic matrix with the magnetic properties of iron oxide enables efficient separation of the sorbent from the treated medium using an external magnetic field. The scientific significance of the study lies in establishing the relationship between the composition and surface characteristics of the magnetic composites and their sorption efficiency. The developed materials can be considered promising sorbents for the treatment of natural and wastewater contaminated with heavy metal ions.