A series of granulated Ni/Al2O3 catalysts were prepared by impregnating the γ-alumina support with a nickel (II) ammine complex solution. The study of catalysts at different stages of preparation using IR and UV–Vis spectroscopy, XRD, thermogravimetric analysis, H2-TPR, TPD-CO2 and O2 chemosorption methods made it possible to trace the evolution of the active component. The interaction between the [Ni(NH3)5(H2O)]2+ cations and γ-Al2O3 results in the partial replacement of NH3 ligands with hydroxyl groups of the support, forming inner-sphere complexes between Ni2+ ions and the Al2O3 surface. Drying the catalyst at 140 °C causes the NH3 ligands in the nickel complexes to be replaced by H2O molecules and/or carbonate ligands. The calcination temperature of 300 °C is sufficient for decomposition of the active component precursor to NiO. In the calcined samples, almost all of the nickel oxide is strongly bound to the alumina surface. The highest reducibility was achieved for the samples calcined at 300 °C. Increasing the calcination temperature to 400 °C decreases the reduction rate. It was demonstrated that the reduction of oxide precursors (obtained by calcination at 300–400 °C) in an H2 flow at 400 °C leads to the formation of a highly dispersed nickel phase on the γ-Al2O3 surface. The Ni/Al2O3 catalysts synthesized using nickel ammine complexes show 40

In this work, the effect of using an additive of dawsonite NH4Al(OH)2CO3 or scarbroite Al5(OH)13(CO3)·5H2O in the preparation of alumina supports on the properties of CoMo/Al2O3 catalysts was investigated. It was established that the key factor influencing the composition and properties of the active component of the catalyst was the phase composition of the support, which changed depending on the added dawsonite and/or scarbroite powder. According to XRD and UV spectroscopy data, it was found that with the addition of dawsonite, the amorphous phase predominated in the support, which altered the nature of the interaction of the support and the active metals, namely, it reduced the amount of inactive cobalt aluminate compared to the catalyst sample based on the support with scarbroite. Furthermore, the change in the phase composition of the support affected the formation of the active component. For the sample prepared with dawsonite, XPS data showed the formation of more reactive sulfide sites. The addition of dawsonite led to the formation of a looser support surface, which increased the dispersion of the active component particles from 0.35 to 0.58 compared to the catalyst sample based on the support with scarbroite. The described changes in the characteristics of the catalyst with dawsonite led to an increase in catalyst activity, both in the hydrodesulfurization reactions of model feedstock and of real blended gasoil.

This study comparatively investigates the dehydrogenation of primary and secondary alcohols over Raney nickel under mild conditions. Experiments were conducted in a semibatch reactor, where an Ar stream was used to continuously remove H2 from the reaction zone, thereby shifting the equilibrium. The research established a clear correlation between alcohol structure and H2 release across various temperatures at atmospheric pressure. Notably, secondary alcohols exhibited significantly higher dehydrogenation reactivity than primary alcohols under identical conditions. It partly explains low donor activity of primary alcohols in transfer hydrogenation. Additionally, the study examined the influence of aromatic compounds, aniline, benzylamine, phenol, and thiophenol, on the dehydrogenation of 2-octanol at 150 degrees C. Results demonstrated that all four aromatic species suppress H2 release, although through distinct mechanistic pathways.

A novel and promising process for synthesizing cyclohexanone, a precursor of polyamide synthesis, via the comproportionation of phenol and cyclohexanol has been investigated. This process was studied within the temperature range of 200-300 degrees C with the initial substances being used in stoichiometric ratio. The Ni/Al2O3 catalysts, which were prepared using the deposition-precipitation method and characterized by ICP-AES, XRD (including in situ investigation), N2 adsorption-desorption, H2-TPR, CO pulse adsorption, and FTIR spectroscopy, were employed in this study. The present study established a correlation between conversions of phenol and cyclohexanol into cyclohexanone over Ni/Al2O3 catalysts and the accessible Ni0 surface area. Furthermore, kinetic analysis of the experimental data has demonstrated that the suggested Ni-based catalysts exhibit high activity in the explored process.

This study investigates the impact of water impurities on the performance and stability of lanthanum-promoted CoMoP/Al2O3-La and NiMoP/Al2O3-La catalysts. Catalysts were tested in a fixed-bed reactor using a model feedstock with dibenzothiophene, with activity monitored before, during, and after the introduction of a 10 vol % water cofeed. A comprehensive characterization suite (HRTEM, XRD, XPS, SEM-EDX) linked performance to structural properties. It is shown that both catalysts deactivated upon water injections, the CoMoP/Al2O3-La catalyst suffered a >10-fold increase in the residual sulfur content in the hydrogenated product compared to only a 3-fold increase for the NiMoP/Al2O3-La catalyst. These results correlate well with activity tests of the catalysts without La. HRTEM data showed that the stacking number of active component particles in the NiMoP/Al2O3-La catalyst increased slightly, while particle length remained unchanged, whereas the CoMoP/Al2O3-La catalyst underwent significant reconstruction, its stacking number decreased from 1.8 to 1.5 and its particle length increased from 3.0 to 3.5 nm, indicating disintegration of the sulfide active component particles. XRD data further showed greater hydrothermal alteration of the gamma-Al2O3 support lattice in the CoMoP/Al2O3-La catalyst. This was coupled with extensive migration and aggregation of lanthanum, which was effectively suppressed in the NiMo system, suggesting nickel clusters anchor the promoter and stabilize the support. XPS analysis data showed that the NiMoP/Al2O3-La catalyst demonstrates fundamentally superior hydrothermal stability due to robust NiMoS phases and a synergistic Ni-La interaction that mitigates water-induced structural degradation.

Catalytic transfer hydrodechlorination of chlorobenzene using 2-propanol as the hydrogen donor and a mixed Ni-Mo sulfide phase deposited on alumina as the catalyst is studied at temperatures 250-300 degrees C. When triethylamine is applied as the HCl neutralizer, benzene is the only product, whereas with inorganic bases (iso)propylbenzenes are also formed.

Ethanol is one of the promising sources of hydrogen (synthesis gas), including in various energy applications. The production of synthesis gas from ethanol is possible in various ways, for example, such as steam and steam-air conversion, which are endothermic and thermoneutal reactions, respectively. Control and management of heat and mass transfer during the occurrence of these reactions is an important task, which can be solved through the use of catalysts on heat-conducting metal substrates. This paper presents the results of a study of the physicochemical properties of Pt, Rh, Pd, Ru, Ni, Co-containing structured catalysts deposited on a FeCrAl mesh support, studied in the processes of steam and steam-air conversion of ethanol. Among the tested samples, the ruthenium catalyst showed the greatest efficiency in the processes of steam and steam-air conversion of ethanol, providing an equilibrium composition of the products without visible signs of carbonization.

BACKGROUND SAPO-11 is known to be an active and selective component of isomerization catalysts. Ni2P/SAPO-11 catalysts are promising in one-step hydrodeoxygenation-hydroisomerization (HDO-HIS) of fatty acid-based feedstocks. But strong interaction with the support and inappropriate acidity can result in low activity and selectivity. Boron is a promising modifier which is capable of solving both of the problems.RESULTS SAPO-11 powders were synthesized using different Si/Al ratios (0.05, 0.10, 0.15). Boron was used as a modifier ((B)SAPO-11) to tune the acidity and surface properties of the materials (B/Al = 0.15). A 70:30 mass ratio of (B)SAPO-11 and AlOOH was used to synthesize supports for Ni2P catalysts. The catalysts were prepared by in situ phosphidation of Ni/(B)SAPO-11-Al2O3 and were tested in methyl palmitate HDO-HIS in a continuous-flow reactor at T = 290-340 degrees C, P = 2.0 MPa, LHSV = 5.3 h-1, H2/liquid = 600 N cm3 cm-3. The supports and catalysts were studied using inductively coupled plasma atomic emission spectrometry, N2 physisorption, NH3 temperature-programmed desorption, X-ray diffraction, transmission electron microscopy and 11B and 31P solid-state NMR. Boron was shown to decrease cracking activity resulting in higher yield of long-chain alkanes.CONCLUSION The highest isomerization activity (80% iso-C15-C16 at 340 degrees C) was shown by the sample with Si/Al = 0.10 due to optimal amount of acid sites. Boron proved to be an efficient component to tune SAPO-11 acidity and decrease cracking at 340 degrees C. (c) 2025 Society of Chemical Industry (SCI).

The paper describes the properties of hydroxoaluminocarbonates (dawsonite NH4Al(OH)2CO3, scarbroite Al5(OH)13(CO3)·5H2O) and their application as additives in alumina synthesis. Comparing scarbroite and dawsonite, it was found that the size of the coherent scattering region of scarbroite (25.0–40.0 nm) was higher than that of dawsonite (11.0–22.0 nm). According to FTIR spectra, scarbroite calcined at 550 °C has higher amount of residual surface CO32–groups than calcined dawsonite. The presence of CO2 in calcined scarbroite was confirmed with IR-Fourier analysis of gas decomposition products. The Al2O3 samples prepared by calcination of hydroxoaluminocarbonates at 550 °C contained X-ray amorphous phase. The Al2O3 sample obtained from scarbroite contained a small amount of γ-Al2O3. By addition of dawsonite/scarbroite to pseudoboehmite for granulated aluminum oxide, it was possible to significantly increase the specific surface area from 223 to 243–298 m2/g, pore volume from 0.48 to 0.62–0.81 cm3/g and water capacity from 0.49 to 0.9–1.2 cm3/g.

Ceria-supported copper catalysts exhibit high catalytic performance in the preferential oxidation of CO in excess H2 (CO PROX). Highly dispersed copper oxide species have been experimentally identified as active centers. However, structural diagnostics of highly dispersed CuOx species and CuOx/CeO2 interface areas remains a challenge. Here, we report a comprehensive structural study of a supported CuO/CeO2 catalyst (5 wt

For the first time, Co/Al2O3 catalysts were studied in selective hydrogenation of p-iodonitrobenzene in a continuous flow reactor. The focus was on the effect of temperature treatment conditions on the catalytic properties of the catalysts. A series of highly loaded cobalt catalysts (20% Co/Al2O3) were prepared via a melt infiltration method in one stage with subsequent calcination (250-450 degrees C) and reduction (400-600 degrees C during 0-6 h). According to the results of physicochemical studies of the samples, the catalytic activity of catalysts differs due to the difference in the amount of nitrate residues, strength of Co interaction with the support, and degree of Co reduction. The highest conversion of p-iodonitrobenzene (96%) and selectivity to p-iodoaniline (97%) were achieved over the Co/Al2O3 catalyst calcined at 400 degrees C and reduced at 500 degrees C.

Heterogeneous catalysts xRu/Ce0.75Zr0.25O2 (x = 1, 5 wt.

The effect of different types of alcohols used as hydrogen donors on the activity of a metal Ni-based catalyst in the hydrogenation of benzofuran as a model substrate under transfer hydrogenation conditions has been studied. The hydrogenation process of benzofuran using 2-PrOH as a hydrogen donor leads sequentially to dearomatization and then to deoxygenation of the substrates. At the same time, the use of primary alcohols such as MeOH, EtOH and 1-PrOH as hydrogen donors leads to irreversible deactivation of the Ni-containing catalyst. A clear mechanism of deactivation of Ni-based metal catalysts by primary alcohols has been established. The interaction of the catalyst with primary alcohols at a temperature of 250 °C leads to the formation of an inactive Ni3C carbide phase, as well as sintering and segregation of metal particles on the surface of the alumina support.

A series of Ni2P catalysts on an Al2O3-SAPO-11 composite support were synthesized by two different methods: reduction of Ni and P precursors by hydrogen at elevated temperatures (TPR); and phosphidation of supported Ni metallic particles by triphenylphosphine (PPh3). For loading active components, aqueous solutions prepared from different precursors (specifically, Ni(OAc)2 and (NH4)2HPO4; Ni(OH)2 and H3PO3; and Ni(OAc)2 and H3PO2) were used in the first case, and a Ni(OAc)2 solution was used in the second. The catalysts were characterized by chemical analysis, H2-TPR, NH3-TPD, XRD, TEM, XPS, and 27Al M­­AS NMR. The catalyst performance was tested in hydroprocessing of a model compound of fatty acid triglycerides, specifically methyl palmitate (MP). The formation of a Ni2P phase was confirmed by XRD, TEM, and XPS; moreover, the synthesis method was found to affect the localization of Ni2P nanoparticles. It was further revealed that, in the TPR method, the particles are predominantly located on the Al2O3 surface, whereas the PPh3 method produces particles on the surfaces of both Al2O3 and SAPO-11. The main MP conversion products are n- and iso-alkanes (C15 and C16). At 100

The paper describes in detail the procedure for the preparation of a granular bulk NiMoW catalyst and a supported reference NiMo/Al2O3 catalyst. Mention is made of investigations of the supported and bulk catalysts by various physico-chemical methods (nitrogen adsorption-desorption method, X-ray photoelectron spectroscopy, TPD-NH3, HRTEM and X-ray diffraction analysis). The experiments to estimate catalytic activity and compare rate constant of hydrodesulfurization of dibenzothiophene using both catalysts have been carried out. It is shown that textural properties of the catalysts significantly differ. The supported catalyst has more developed specific surface area and pore volume than the bulk catalyst. TPD-NH3 showed an increased acidity of the supported catalyst in comparison the bulk catalyst. It is shown by the X-ray photoelectron spectroscopy method that in both samples Mo on the surface is present exclusively in the form of Mo4+ ion. However, the bulk catalyst differs from the supported catalyst in that it contains a larger amount of Ni as part of the active NiMo(W)S phase. The catalytic activity tests demonstrated that the bulk catalyst is more active at 240, 250 and 260°C, it is discovered that the rate constant in hydrodesulfurization of dibenzothiophene for the bulk NiMoW catalyst is twice higher at 240ºC than that of the supported NiMo/Al2O3 catalyst.

In this work, NiO and NiO–SiO2 are studied using X-ray diffraction and the method of atomic-pair radial distribution. Using X-ray phase analysis, it is determined that the sizes of NiO particles have a coherent-scattering region of more than 100 nm, while the NiO–SiO2 sample has particle sizes of about 2–3 nm. However, full-profile simulation using the Rietveld method does not allow one to describe the effects observed during diffraction: asymmetry of the peaks, the appearance of an additional shoulder of peak 111 in the region of small angles; therefore, the method of atomic-pair radial distribution is used to analyze the structure. When simulating the experimental curve of the atomic-pair radial distribution, 3 different models are used: pure NiO, a mixture of NiO and Ni2SiO4, as well as a modified NiO model with Si embedded into the crystal lattice. The latter model is created based on the assumption of the incorporation of silicon into the NiO structure, as can be evidenced by the X-ray diffraction data. According to the results of simulation of the curve of the atomic-pair radial distribution, it is the latter model that provides the best description of the observed effects: a significantly increased unit-cell parameter in comparison with the sample without the addition of SiO2, as well as decreased cation–oxygen distances in the structure while the distances between cations are increased.

This paper presents a study on the effect of the Ni-Mo-W precursor calcination (300, 450 and 500 degrees C) on properties of granulated bulk Ni-Mo-W catalysts. The Ni-Mo-W precursor and bulk catalysts were studied by XRD, nitrogen adsorption-desorption method, CHNS analysis, thermal analysis, Raman spectroscopy, UV-Vis DR spectroscopy, HRTEM and XPS. It is shown that the increase in calcination temperature of the precursor to 500 degrees C leads to stepwise decomposition of citric acid, transformation of active metals and re-structurization of the samples. Active metals in sulfide catalysts are present in the bulk mixed or individual sulfides and interact with alumina binder to form "NiMoS-like" sulfide phase. Increased crystallinity of the precursor results in the enlargement of bulk nickel particles, capsulation of Mo and W and their rounding by Ni atoms. Catalysts testing in hydrotreatment of SRVGO demonstrates that the best choice of temperature regimes is 300 degrees C for the precursor.

In this study, supported 5 wt% Ru/Ce0.75Zr0.25O2 catalysts were prepared by sorption-hydrolytic deposition technique, followed by calcination under different conditions, namely in reductive H2/N2 (Ru/CeZr_red) and oxidative air (Ru/CeZr_ox) atmospheres. A thorough characterization of the catalysts was carried out by XRD, CO chemisorption, HRTEM, Raman spectroscopy, XPS, and in situ DRIFTS. The findings showed that the choice of the calcination atmosphere has a great impact on the structural organization of the catalyst. Calcination in air results in the formation of the larger crystalline RuO2 particles, which tend to enlarge upon reduction under CO2 methanation conditions. The reductive treatment results in a much higher dispersion of supported Ru species and a more pronounced metal-support interaction (MSI). In the Ru/CeZr_red catalyst, a large amount of atomic scale Ru species was detected along with metallic Ru nanoparticles and clusters. However, it was found that the superiority of the Ru/CeZr_red catalyst in the Ru dispersion did not result in the significant advantage in the CO2 methanation activity. In situ DRIFTS results suggested that the MSI affects the ability of Ru species to adsorb and activate reagent molecules, in particular, enhances the adsorption strength of the intermediate CO species.

Pt/Ce1-xZrxO2 catalysts have shown high activity in water gas shift (WGS) reaction, but their structural organization has been studied insufficiently. This work represents a detailed structural study on the supported Pt species and the metal/support interface in a 5 wt% Pt/Ce0.75Zr0.25O2 catalyst in the initial state, after reductive activation, and after WGS reaction in H2-enriched reformate-simulating mixture. A wide range of methods was used: ex situ and in situ X-ray diffraction (XRD) studies, high resolution transmission electron microscopy (HRTEM), X-ray atomic pair distribution function (PDF) method, pseudo in situ X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H2-TPR). The Ce0.75Zr0.25O2 mixed oxide was shown to provide a highly dispersed state of Pt species. XPS revealed that the initial catalyst contains Pt2+species. PDF analysis allowed us to propose the structure of ultrafine PtO particles and to elucidate the metal-support interaction with fixation of Pt ions on the support surface. In situ XRD, pseudo in situ XPS, and H2-TPR studies revealed the reduction of ultrafine PtO particles in H2 atmosphere at low temperatures (20-90 degrees & Scy;) with the formation of metallic Pt0 particles and simultaneous partial reduction of the support surface due to the hydrogen spillover. Catalytic tests of the as-prepared and poisoned with chlorine 5wt% Pt/Ce0.75Zr0.25O2 catalysts in the WGS reaction showed an important role of the oxygen vacancies in the oxide support as active sites. These findings contribute to the understanding catalytic performance of Pt/Ce1-xZrxO2 systems.

Методом сорбционно-гидролитического осаждения приготовлены гетерогенные катализаторы состава хRu/Ce0.75Zr0.25O2 (x=1, 5 масс. %). Показано, что катализаторы активны в реакции метанирования диоксида углерода. Проведена комплексная диагностика состава и структурных особенностей катализаторов с использованием методов порошковой рентгеновской дифракции, электронной микроскопии высокого разрешения, хемосорбции, а также рентгеновской фотоэлектронной спектроскопии (РФЭС). Показано, что метод сорбционно-гидролитического осаждения позволяет получать катализаторы с высокодисперсным состоянием активного компонента. Катализатор с 1 масс. % Ru содержит соединения рутения в виде атомарных кластеров, в катализаторе с 5 масс. % наряду с ультрадисперсными формами образуются окристаллизованные рутенийсодержащие частицы. Установлено, что исходные катализаторы содержат оксидные соединения рутения, которые в условиях реакции метанирования претерпевают восстановление до металлического состояния. Результаты in situ диагностики методами порошковой дифракции и РФЭС, а также термопрограммируемого восстановления водородом (H2-ТПВ) показали, что в процессе активационной обработки катализаторов нагревом в обогащённой водородом газовой среде образующиеся кластеры или частицы металлического рутения промотируют процесс частичного восстановления оксидного носителя за счет спилловер эффекта.