Ru-containing Catalysts Research Articles

Synthesis and Study of Ru-Containing Catalysts on Mesostructured Carbon for Glucose Hydrogenation

Synthesis and Study of Ru-Containing Catalysts on Mesostructured Carbon for Glucose Hydrogenation

Cs-promoted hydrogenation upgrading of bio-oil over macroporous Ru-containing catalysts using model compounds

Hydrogenation upgrading is an effective technique that lowers the oxygen content of bio-oil with the aim of improving its quality. In order to fabricate a series of Ru-based catalysts for the hydrodeoxygenation of bio-oil, several all-silica supports with different pore sizes are synthesized and modified with Al and Cs in this work. The physical morphology and electronic structure of the catalysts are characterized using multiple techniques including X-ray diffraction, in-situ pyridine adsorption infrared spectroscopy, in-situ diffuse reflectance Fourier transform infrared spectroscopy, Raman spectroscopy, CO2 temperature-programmed desorption, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and N2 physical adsorption-desorption testing. Phenol, guaiacol, anisole and o-cresol are selected as model compounds to investigate the hydrodeoxygenation reactivity of the catalysts. The results reveal that there is a strong linear correlation between the pore size of the catalysts and the rates of the hydrogenation and hydrodeoxygenation of phenol. Importantly, both the oxygen vacancy density and relative content of Brønsted and Lewis sites (B/L) of the catalysts can be greatly increased by Cs modification, which further linearly promotes the hydrodeoxygenation activity of the catalysts. In addition, the in-situ infrared spectroscopy results show that the catalysts modified by Al and Cs heterolytically cleave H2 to supply H+ for the reaction. This work presents a novel approach for fabricating catalysts employed in the hydrotreatment process of bio-oil.

Hydrodeoxygenation of guaiacol over halloysite nanotubes decorated with Ru nanoparticles: Effect of alumina acid etching on catalytic behavior and reaction pathways

Halloysite nanotubes (HNTs) is a promising support for liquid-phase hydrodeoxygenation (HDO) catalysts due to a wide abundance, low cost and tunable properties. Acid etching of halloysite by sulfuric acid was found to enlarge lumen diameter (24.3 nm), enhance specific surface area (154 m2/g) and acidity (0.343 mmol/g). Based on pristine and dealuminated HNTs, Ru-containing catalysts were synthesized via impregnation under microwave irradiation. The catalytic properties of synthesized catalysts in HDO of guaiacol were studied in batch reactors at 120–180 °C, under hydrogen pressure of 3 MPa, with guaiacol/Ru molar ratio of 200 in water as a solvent. Comparing the results of catalytic tests, we have concluded that the catalysts based on etched halloysite enhanced greater activity (TOF – 211 h−1) in the HDO of guaiacol compared their analogue supported on pristine HNTs. Moreover, the Ru-catalyst based on etched HNTs contributed to an increase selectivity to hydrogenolysis with effective oxygen removal.

Gram-scale ruthenium catalysts templated on halloysite nanotubes and MCM-41/halloysite composite for removal of aromatics from gasoline fraction

Effective and low-cost gram-scale Ru-containing catalysts for removal of aromatics from the gasoline fraction while retaining the octane number.

ZSM-5 as a support for Ru-containing catalysts of levulinic acid hydrogenation: Influence of the reaction conditions and the zeolite acidity

Levulinic acid (LA) is a substance, which can be obtained from cellulosic biomass and hydrogenated to gamma-valerolactone (GVL) – important platform chemical. This work describes the study of a ruthenium-containing catalysts synthesized by the impregnation of HZSM-5 having different silicate modulus (40, 80 or 400) with ruthenium precursor, which resulted in formation of oxidized Ru(III) and Ru(IV) species on the catalyst surface. Synthesized catalysts allowed more than 98% of LA conversion for 60 min of the reaction and 100% GVL selectivity while working at relatively mild conditions (100 °C, 1 MPa of H2) in aqueous medium. It was demonstrated that the observed catalytic activity mainly depends on two factors: (i) concentration of strong Lewis acid centers on the catalyst surface and (ii) surface content of RuO2, since the synthesized catalysts needed no preliminarily activation procedure.

Hydrogen production by steam reforming of propane and LPG over supported metal catalysts

The steam reforming of propane and LPG has been investigated over Ru, Rh, Ir, Pt, Pd and Re catalysts (1 wt%) dispersed on commercial metal oxide supports (Al2O3, TiO2, CeO2-ZrO2). The Ru and Rh catalysts exhibit higher activity, which is comparable to that of a reference 10%Ni/Al2O3 sample. The performance of the Al2O3-supported Rh and 10%Ni catalysts deteriorates with time-on-stream due to the deposition of polymeric (Cβ) and/or vermicular (CV) carbon. The Ru-containing catalysts are considerably more stable because of the formation of small amounts of easily gasified carbon. Best results were obtained for the Ru/CeO2-ZrO2 catalyst, which is characterized by high activity, high selectivity toward H2 and excellent stability with time-on-stream. This has been attributed to the formation of, mainly, monoatomic carbon (Cα) species under reaction conditions, the high efficiency of Ru to gasify carbon deposits, and the presence of labile lattice oxygen species on the CeO2-ZrO2 support.

Features of the noble metals impregnation into the polymeric matrix of hyper-cross-linked polystyrene

Commercial hyper-cross-linked polystyrene (HCLPS) was shown to be a promising support for the development of heterogeneous catalysts intended for fine organic synthesis. This paper summarizes the results of multiyear studies on the creation of heterogeneous Pd-, Ptand Ru-containing catalysts based on MN100 and MN270 HCLPS. Data obtained by characterization of HCLPS and the related catalysts using various physical and physicochemical methods are reported. It was shown that commercial HCLPS can be used in the catalyst synthesis as spherical grains or as a powder. The form of HCLPS, along with the features of the metal catalyst precursor, essentially affect the distribution of Pd, Pt and Ru compounds and the sizes of metal-containing nanoparticles formed in the polymer environment. In addition, this is the first study that considers in detail the effect of catalyst treatment in flowing hydrogen at 300 °C on the surface chemical composition of the MN100 powder samples impregnated with Pd, Pt and Ru compounds.

Features of the noble metals impregnation into the polymeric matrix of hyper-cross-linked polystyrene

Commercial hyper-cross-linked polystyrene (HCLPS) was shown to be a promising support for the development of heterogeneous catalysts intended for fine organic synthesis. This paper summarizes the results of multiyear studies on the creation of heterogeneous Pd-, Ptand Ru-containing catalysts based on MN100 and MN270 HCLPS. Data obtained by characterization of HCLPS and the related catalysts using various physical and physicochemical methods are reported. It was shown that commercial HCLPS can be used in the catalyst synthesis as spherical grains or as a powder. The form of HCLPS, along with the features of the metal catalyst precursor, essentially affect the distribution of Pd, Pt and Ru compounds and the sizes of metal-containing nanoparticles formed in the polymer environment. In addition, this is the first study that considers in detail the effect of catalyst treatment in flowing hydrogen at 300 °C on the surface chemical composition of the MN100 powder samples impregnated with Pd, Pt and Ru compounds.

Hydrolytic Hydrogenation of Cellulose with the Use of the Ru-containing Polymeric Catalysts

The study presents the results of cellulose hydrolytic hydrogenation process in subcritical water in the presence of Ru-containing catalysts based on hypercrosslinked polystyrene (HPS) MN-270 and its functionalized analogues: NH2-HPS (MN-100) and SO3H-HPS (MN-500). It was shown that the replacement of the traditional support (carbon) by HPS increases the yield of the main cellulose conversion products – polyols – important intermediates for the chemical industry. The catalysts were characterized using transmission electron microscopy (TEM), high resolution TEM, and porosity measurements. Catalytic studies demonstrated that the catalyst containing 1.0% Ru and based on MN-270 is the most active. The total yield of sorbitol and mannitol was 50% on the average at 85% cellulose conversion.

Hydrogenation of Levulinic Acid to γ-Valerolactone in the Presence of Ru-Containing Catalysts Based on Carbon Material “Sibunit”

Nanostructured 1 and 3% catalysts containing ruthenium nanoparticles supported on the initial and oxidized at different temperatures graphite-like carbon material Sibunit-4 prepared. A features of this support are mesoporous texture, hydrothermal stability and the presence of surface oxygen-containing functional groups responsible for the distribution of Ru nanoparticles and the catalyst acidic properties. The catalysts characterized using methods TEM, XPS, N2 adsorption, pHpzc and tested in the hydrogenation of levulinic acid to γ-valerolactone. It was found that the reaction rate and GVL selectivity are influenced by solvent choice, fractional composition, and acidic properties of the support. The obtained catalysts provide high activity in the reaction of direct hydrogenation of levulinic acid to γ-valerolactone (GVL yield 98 mol.%, At 160°С, 1.2 MPa H2) and high productivity (15.9 gGVL/gCat.). Obtained catalyst can be reused several times without noticeable loss of activity

Surface interactions with the metal oxide surface control Ru nanoparticle formation and catalytic performance

Here, we report the development of novel Ru-containing catalysts based on porous metal oxide supports such as SnO2, Nb2O5, and Nb2Sn5O15. We assessed structure, porosity, acidity and morphology of both supports and catalysts and established a relationship between surface interactions and catalytic performance in hydrogenation of biomass based levulinic acid (LA) to γ-valerolactone (GVL). All metal oxide supports stabilize small Ru-containing nanoparticles (NPs), whose makeup includes a prevailing fraction of Ru(OH)3. Yet, Nb2O5 stabilizes ∼1 nm Ru-containing NPs which are homogeneously distributed on the metal oxide surface, while for SnO2 and Nb2Sn5O15, sub-nanometer NPs are formed, which are prone to aggregation to minimize surface energy. These differences are assigned to nucleation of NPs on support oxygen vacancies, whose amounts vary and are consistent with NP characteristics. The catalytic testing shows that the 100 % conversion and selectivity as well as high turnover frequency are achieved for Ru/Nb2O5, whose surface morphology includes well-dispersed 1 nm Ru-containing NPs. These and high stability of catalytic performance upon multiple reuse, make Ru/Nb2O5 promising for practical applications. Furthermore, this work validates the usefulness of surface interactions on metal oxides in development of efficient catalytic systems.

Ring-opening and hydrodenitrogenation of indole under hydrothermal conditions over Ni, Pt, Ru, and Ni-Ru bimetallic catalysts

The activity and selectivity of activated-carbon-supported Ni, Pt, Ru, and Ni-Ru bimetallic catalysts was examined for hydrothermal denitrogenation of indole. The molar yield of pyrrole ring-opening compounds, without an added hydrogen source, are in the order: Ni < Pt < Ni90Ru10 < Ni75Ru25 < Ni50Ru50 ~ Ni25Ru75 ~ Ru. Ru-containing catalysts facilitated production of hydrocarbons (hydrodenitrogenation (HDN) products) when used with added formic acid (hydrogen source). We elucidated catalytic hydrothermal HDN pathways for indole based on the product distributions and the variation of their yields with time. Hydrogenation of indole to indoline is the primary pathway and ring-opening of indoline to form alkyl anilines is faster than forming HDN products (alkyl benzenes). DFT calculations confirmed experimental activity trends, showing Ru is more active than Ni for indole ring opening and for o-toluidine deamination. If no hydrogen source is present, directly breaking the N-C bond in the pyrrole ring is more favorable than breaking the C-N bond with an aromatic carbon. If a H source is provided, the pyrrole ring hydrogenates first, forming indoline, followed by cleavage of the C-N bond.

Effect of the ruthenium deposition method on the nanostructured catalyst activity in the deep hydrogenation of benzene

Ru-containing catalysts supported on halloysite aluminosilicate nanotubes (HNTs) were prepared by incipient wetness impregnation, vacuum impregnation, and impregnation under the microwave irradiation methods. Composition and structure of the catalysts were determined by X-ray fluorescence (XRF), thermo-programmed reduction (TPR-H2), and transmission electron microscopy (TEM). Textural characteristics were detected by low-temperature nitrogen adsorption—desorption. The activity of the catalysts was investigated in benzene hydrogenation at 80°?, a hydrogen pressure of 3.0 MPa, and a molar ratio of benzene to Ru of 2000. It was found that Ru nanoparticles prepared by vacuum impregnation are deposited mainly into the internal cavity of aluminosilicate nanotubes, while in samples obtained by wetness impregnation the active phase is formed predominantly on the external surface of halloysite. The catalyst prepared by impregnation under microwave irradiation is characterized by a high Ru content, its uniformly distributed metal particles are located mainly on the external surface of HNT, and it demonstrated the superior activity in hydrogenation of benzene to cyclohexane.

Magnetically separable Ru-containing catalysts in supercritical deoxygenation of fatty acids

Abstract In the current paper, the possibility of the use of magnetically separable catalysts containing ruthenium oxide species in the supercritical deoxygenation of stearic acid for producing of the second generation of biodiesel is reported. Three different supports (silica, ceria, and hypercrosslinked polystyrene) were used for the stabilization of magnetic nanoparticles (MNPs) and Ru-containing particles. The effect of support on the magnetic properties as well as the catalytic activity of the obtained systems was studied. All synthesized catalysts were shown to provide high stearic acid conversion (up to 95 %). The highest yield of C17+ hydrocarbons (up to 86 %) was observed while using the Ru–Fe3O4-HPS system. Ru–Fe3O4-HPS was characterized by the high values of the specific surface area (364 m2/g) and saturation magnetization (4.5 emu/g). The chosen catalytic system was found to maintain its catalytic activity for a minimum of 10 consecutive cycles.

Ru-содержащие катализаторы для жидкофазного синтеза Фишера-Тропша

The search for new stable and active catalysts of Fischer-Tropsch synthesis is one of the key directions for production of liquid fuels from alternative raw materials. Stabilization of the active phase is the main task in the development of catalysts for hydrogenation of CO into liquid fuels. This problem can be solved by choosing the optimal support, as well as the synthesis method. This work is devoted to the development of new polymer mono– and bimetallic Ru-containing catalysts for liquid phase Fischer-Tropsch synthesis. It is shown that the use of 1% Ru-HPS and 10% Co — 1% Ru-HPS allows to obtain a high yield of gasoline hydrocarbons (more than 70%), providing a high conversion of CO (up to 23%). The selected polymer-based systems showed high stability in the Fischer-Tropsch synthesis process.

Ru-Containing Catalysts for Methanol and Ethanol Steam Reforming in Conventional and Membrane Reactors

We have carried out a comparative study of the catalytic activity of nanostructured M–Ru (M = Pt, Pd, Rh) bimetallic catalysts supported on detonation nanodiamond (DND) for methanol steam reforming (MSR) and ethanol steam reforming (ESR) processes in a conventional and a membrane reactor. The catalysts have been characterized by X-ray diffraction, transmission electron microscopy, and BET measurements. In the ESR process, the highest hydrogen yield is ensured by the Pt–Ru/DND catalyst, whereas the Ru–Rh/DND catalyst exhibits the highest activity for the MSR reaction. Our results demonstrate that, if the processes in question are run in a membrane reactor with a Pd–Ru membrane, there is a stable hydrogen flow, free of CO and other impurities, in the permeate zone even at temperatures on the order of 400°C.

Hydrogenation of Furfural to Furfuryl Alcohol in the Presence of Ru-Containing Catalysts Based on New Zeolite-Like Materials

Catalytic liquid-phase hydrogenation of furfural to commercially important furfuryl alcohol was studied in the presence of Ru-containing catalysts based on Sibunit and zeo-type materials, such as nickel phosphate molecular sieves (VSB-5 and Fe-VSB-5) and zirconium-containing metal–organic frameworks (UiO-66(Zr)-R, R = H and NH2), at 30 and 50°C and 5–25 atm of hydrogen. The yield of furfuryl alcohol was found to depend on the nature of the support and increases in the following order: Ru/UiO-66(Zr)-NH2 < Ru/UiO-66(Zr) < Ru/Fe-VSB-5 < Ru/VSB-5. The effect of hydrogen pressure and temperature on the selectivity toward furfuryl alcohol was investigated.

The kinetics of catalytic hydrogenation of nitrobenzene in the presence of Ru-containing catalysts

The kinetics of catalytic hydrogenation of nitrobenzene in the presence of Ru-containing catalysts

Nanostructured Ruthenium Catalysts in Hydrogenation of Aromatic Compounds

Ru-containing catalysts based on aluminosilicate halloysite nanotubes (HNTs) are synthesized by preliminary functionalization of the support surface by aminopropyltriethoxysilane (APTES) followed by the microwave-assisted deposition of ruthenium to provide the intercalation of metal nanoparticles into the inner space of nanotubes. The composition and structure of the synthesized catalysts are studied by X-ray fluorescent analysis, low-temperature nitrogen adsorption/desorption, transmission electron microscopy, and hydrogen temperature-programmed reduction. The activity of the catalysts in benzene hydrogenation at a temperature of 80°С and a hydrogen pressure of 3 MPa both in the hydrocarbon medium and in the two-phase system with water is studied. It is shown that, in the presence of water, the hydrogenating activity of the catalyst based on modified halloysite nanotubes is considerably higher than that of the sample prepared using the initial halloysite as a support.

Hydrogenation of Furfural to Furfuryl Alcohol in the Presence of Ru-Containing Catalysts Based on New Zeolite-like Materials

Liquid-phase catalytic hydrogenation of furfural to industrially important furfuryl alcohol was studied at 30 and 50 °C and 2 to 24 atm hydrogen pressure in the presence of Ru-containing catalysts based on new zeolite-like materials such as nickel-phosphate molecular sieves (VSB-5 and Fe-VSB-5) and zirconium-containing organometallic frameworks (UiO-66(Zr)-R, R = H and NH2), as well as materials based on carbon support Sibunit (for comparison). The yield of furfural was shown to depend on the support nature and to increase in the series: Ru/UiO-66(Zr)-NH2 &lt; Ru/UiO-66(Zr) &lt; Ru/Fe-VSB-5 &lt; Ru/VSB-5. The influence of the hydrogen pressure and temperature on selectivity to furfural alcohol was studied.