Recently, the use of plant-origin materials has become especially important due to the aggravation of environmental problems and the shortage and high cost of synthetic materials. One of the potential candidates among natural organic compounds is polysaccharides, characterized by a number of advantages over synthetic polymers. In recent years, natural polysaccharides have been used to design composite catalysts for various organic syntheses. This review is devoted to the current state of application of polysaccharides (chitosan, starch, pectin, cellulose, and hydroxyethylcellulose) and composites based on their catalysis. The article is divided into four main sections based on the type of polysaccharide: (1) chitosan-based nanocomposites; (2) pectin-based nanocomposites; (3) cellulose (hydroxyethylcellulose)-based nanocomposites; and (4) starch-based nanocomposites. Each section describes and summarizes recent studies on the preparation and application of polysaccharide-containing composites in various chemical transformations. It is shown that by modifying polysaccharides, polymers with special properties can be obtained, thus expanding the range of biocomposites for catalytic applications.

In this study, we investigated the influence of polymer nature and support characteristics on the performance of Pd-based heterogeneous catalysts. Catalysts were prepared via sequential adsorption of poly(4-vinylpyridine) (P4VP) or chitosan (CS) and palladium ions onto MgO and SBA-15 supports under ambient conditions. The resulting hybrid materials were characterized by IR spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectra (XPS). TEM analysis revealed that Pd nanoparticles with an average size of 2–3 nm were well-dispersed on P4VP/MgO, while larger and less uniformly distributed particles (8–10 nm) were observed on SBA-15-based systems. Catalytic tests in the hydrogenation of 2-propen-1-ol, phenylacetylene, and 2-hexyn-1-ol under mild conditions (40 °C, 1 atm H₂, ethanol) demonstrated that both the support and polymer type significantly influence activity and selectivity. P4VP-modified catalysts outperformed CS-containing analogs in all reactions. MgO-based systems showed higher activity and selectivity in 2-propen-1-ol hydrogenation compared to SBA-15-based catalysts. The 1%Pd–P4VP/MgO catalyst exhibited the best performance, with a reaction rate of 5.2 × 10⁻⁶ mol/s, 83.4% selectivity to propanol, and stable activity over 30 consecutive runs. In phenylacetylene and 2-hexyn-1-ol hydrogenation, all catalysts showed high selectivity to styrene (93–95%) and cis-2-hexen-1-ol (96–97%), respectively. The incorporation of P4VP polymer into the Pd/MgO catalyst leads to smaller and better-distributed palladium particles, resulting in enhanced catalytic activity and stability during hydrogenation reactions. These results confirm that the choice of polymer modifier and inorganic support must be tailored to the specific reaction, enabling the design of highly active and selective polymer-modified Pd catalysts for selective hydrogenation processes under mild conditions.

In this study, we investigated the influence of polymer nature and support characteristics on the performance of Pd-based heterogeneous catalysts. Catalysts were prepared via sequential adsorption of poly(4-vinylpyridine) (P4VP) or chitosan (CS) and palladium ions onto MgO and SBA-15 supports under ambient conditions. The resulting hybrid materials were characterized by IR spectroscopy, SEM, TEM, and XPS. TEM analysis revealed that Pd nanoparticles with an average size of 2–3 nm were well-dispersed on P4VP/MgO, while larger and less uniformly distributed particles (8–10 nm) were observed on SBA-15-based systems. Catalytic tests in the hydrogenation of 2-propen-1-ol, phenylacetylene, and 2-hexyn-1-ol under mild conditions (40 °C, 1 atm H₂, ethanol) demonstrated that both the support and polymer type significantly influence activity and selectivity. P4VP-modified catalysts outperformed CS-containing analogs in all reactions. MgO-based systems showed higher activity and selectivity in 2-propen-1-ol hydrogenation compared to SBA-15-based catalysts. The 1%Pd–P4VP/MgO catalyst exhibited the best performance, with a reaction rate of 5.2 × 10⁻⁶ mol/s, 83.4% selectivity to propanol, and stable activity over 30 consecutive runs. In phenylacetylene and 2-hexyn-1-ol hydrogenation, all catalysts showed high selectivity to styrene (93–95%) and cis-2-hexen-1-ol (96–97%), respectively. These results confirm that the choice of polymer modifier and inorganic support must be tailored to the specific reaction, enabling the design of highly active and selective polymer-modified Pd catalysts for selective hydrogenation processes under mild conditions.

Dry reforming of methane (DRM) is a method whereby two greenhouse gases (methane and carbon dioxide) are synthesized into a high-value gas. Suitable catalysts with optimal compositions are still in development, as problems concerning coking and metal sintering remain unresolved. Since the late 20th century, catalysts prepared via solution combustion synthesis (SCS) have been applied for catalytic reactions, as these materials (catalyst or supports) demonstrate high catalytic performance; for example, SCS catalysts have been tested in DRM. This review describes the history of solution combustion synthesis, compares it with traditional methods of preparing catalysts for DRM, and charts recent developments in SCS catalytic systems based on Ni and Co. SCS catalysts are prepared by burning nitrates (oxidizing agents) and fuels (reducing agents) at mild pre-ignition temperatures. In this review, the effects of fuel type and mixed-fuel systems on the catalyst composition, as well as its activity in DRM, are described. These catalysts have shown high metal dispersion, good coke resistance, and stable catalytic performance in long-term tests. This review demonstrates the main reasons for catalyst deactivation, such as coke deposition on the catalyst surface, and suggests ways to reduce them.

This study focuses on the shaping of ZSM–5-based granules using conventional pseudoboehmite as well as aluminum hydroxynitrate precursors obtained by partial thermal treatment of Al(NO₃)₃·9H₂O. The starting materials and nitrate-derived precursors were characterized by X-ray diffraction, thermal analysis, infrared spectroscopy, scanning electron microscopy, and low-temperature nitrogen adsorption. Model pseudoboehmite systems were used to evaluate the effects of moisture, peptization equivalent, and HNO₃ concentration in the initial liquid portion on pore volume, apparent density, shrinkage, and axial and radial crushing strength. Acid peptization showed a strongly non-linear effect: small HNO₃ additions increased strength and densification, whereas excess acid promoted structural heterogeneity and granule disintegration during thermal treatment. Even at constant moisture and total acid dosage, strength depended markedly on the initial peptizer concentration. In unpeptized ZSM–5/pseudoboehmite composites, increasing zeolite content reduced pore volume but increased density and strength, indicating formation of a more compact framework. Aluminum hydroxynitrate precursors enabled effective shaping of ZSM–5-containing pastes, demonstrating their potential as alternative binder precursors, while the optimized pseudoboehmite systems provided the most favorable overall balance between porosity and mechanical stability.

Исследовано влияние формования и модифицирования металлами на кислотные и каталитические свойства формованных композиций ZSM-5–Al₂O₃ для алкилирования ароматических углеводородов. В качестве исходной матрицы использовали формованные материалы на основе ZSM-5 и алюмооксидного связующего, полученного из псевдобемита. Для оценки влияния состава носителя исследовали прокалённый Al₂O₃ и композиции ZSM-5–Al₂O₃, содержащие 50, 70 и 80 мас.% цеолита. Температурно-программированная десорбция аммиака показала, что увеличение содержания ZSM-5 сопровождается ростом интенсивности и площади десорбционных сигналов, а также умеренным смещением максимумов десорбции в область более высоких температур. На основе композиции 50 мас.% ZSM-5 + 50 мас.% Al₂O₃ приготовлена серия Zn–Мекатализаторов, содержащих Zn, Zn–Ce, Zn–La и Zn–Zr. Образцы охарактеризованы методами рентгеновской дифракции, ИК-Фурье-спектроскопии и ИК-Фурьеспектроскопии адсорбированного пиридина. Установлено, что введение металлических компонентов не приводит к выраженному разрушению каркаса ZSM-5, однако для образца Zn–Zr/ZSM-5–Al₂O₃ обнаружены рефлексы ZrO₂. По данным ИК-спектроскопии адсорбированного пиридина во всех Zn–Me-катализаторах преобладают льюисовские кислотные центры; отношение B/L изменяется от 0,18 для Zn–Ce/ZSM-5–Al₂O₃ до 0,36 для Zn–Zr/ZSM-5–Al₂O₃. Каталитические испытания в реакции алкилирования бензола этиленом показали, что максимальная селективность по этилбензолу достигается на Zn–Ce/ZSM-5– Al₂O₃, наибольшая конверсия этилена - на Zn–Zr/ZSM-5–Al₂O₃, а максимальный выход этилбензола - на Zn–La/ZSM-5–Al₂O₃. Полученные результаты показывают, что свойства формованных Zn–Me/ZSM-5–Al₂O₃-катализаторов определяются совместным влиянием состава цеолит-алюмооксидной матрицы и природы металлического модификатора.