Download or read book Synthesis Characterization and Catalytic Performances of Mesoporous Calcium Oxide Supported Nickel in Methane Reforming Reaction written by Ola Samrout and published by . This book was released on 2019 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book New and Future Developments in Catalysis written by Dapeng Liu and published by Elsevier Inc. Chapters. This book was released on 2013-07-11 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dry Reforming of Methane on Nickel Dispersed on Mesoporous Silica written by Joudie Youssef and published by . This book was released on 2015 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: The reduction of greenhouse gases utilization and emission is the main interest of the scientists all over the world. Dry reforming of methane (DRM) is gaining more attention, due to its consumption of two greenhouse gases, namely methane and carbon dioxide, and its production of syngas. Moreover, the products ratio (1:1) of H2: CO is suitable for Fishcher-Tropsch synthesis. DRM is highly endothermic and requires severe conditions to proceed thermodynamically. Thus, the main challenge is the design a catalyst that can maintain its activity and stability under the reaction conditions. Noble metals have showed great catalytic activity and stability when used as an active phase in DRM catalysts. However, their use is not favored to economic an accessibility reasons. Nickel-based catalysts are an affordable and available promising alternative for noble metals. Thus, Nickel was used as an active phase in this study. The mesoporous based silica support, Santa-Barbara Amorphous material (SBA-15), used as catalytic supports in DRM, provide good dispersion of the active phase and good prevention to sintering. Thus SBA-15 is chosen as a support for Nickel in this study. The main focus of this thesis is to study the effect of the modifications made during SBA-15 synthesis (acidity, stirring rate, hydrothermal treatment, etc) on the activity/stability performance of Ni-based catalyst. In this study, eight supports SBA-15(x) were prepared and characterized by N2 sorption and showed different textural properties. Then, all the samples were impregnated with 5wt % Nickel using the two solvent impregnation method. Finally, eight catalysts Ni5/SBA-15(x) are obtained. The calcined fresh samples are characterized by N2 sorption, TPR, TEM, SEM and XRD. The results suggest similar SBA-15 structures with a small difference in grains shape .In addition, differences in Nickel particles size and localization are observed. A good dispersion of the Nickel particles is noted for all the catalysts. Catalytic activities are measured with a GHSV of 3600mL.g-1.h-1 at temperatures ranging from 200 to 800°C and atmospheric pressure. Stability measurements are conducted with the same GHSV at a fixed temperature of 650°C for 12 hours. The catalysts showed high activity and selectivity toward DRM. No significant deactivation is observed throughout the stability test.The characterizations by SEM and XRD after the test indicate that no sintering took place. The main cause of the small deactivation is due to coke deposition. Further studies of the spent catalysts by TEM are required to determine the type of coke deposited.

Download or read book Preparation Characterization and Reactivity of NI CE SBA 15 Catalysts in Dry Reforming of Methane written by Marie-Nour Kaydouh and published by . This book was released on 2013 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Effect of Pretreatment Conditions on Catalytic Performances of Mesoporous Ni5 SBA 15 Catalyst in Methane Dry Reforming written by Charbel Harika and published by . This book was released on 2017 with total page 41 pages. Available in PDF, EPUB and Kindle. Book excerpt: Researchers have been studying dry reforming of methane (DRM) to produce syngas, a mixture of hydrogen and carbon monoxide, from methane and carbon dioxide. In this study, catalysts containing 5% wt Ni dispersed on SBA-15 support were prepared by "two solvent impregnation" method. Without prior calcination, three samples were pretreated by reduction under different atmospheres (H2/Ar, N2, Ar) at 450°C with a heating rate of 0.5°C/min. Two other samples were reduced under H2/Ar but at different temperatures and heating rates (650°C with 10°C/min, and 450°C with 0.5°C/min). After the catalysts characterization (N2 sorption, XRD and TPR) and the catalytic tests (activity and stability), Ni5/SBA-15(U-H2) (reduced under H2/Ar at 450°C with a heating rate 0.5°C/min) showed the best catalytic performance among the other catalysts studied. The behavior of Ni5/SBA-15(U-H2) is close to the behavior of Ni5/SBA-15 calcined at 450°C with a heating rate 0.5°C/min.

Download or read book Synthesis and Characterization of Catalysts Containing Nickel for Reforming Methane with Carbon Dioxide written by Michael Edward Sommer and published by . This book was released on 1988 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis Characterization and Catalytic Performance of Novel Cobalt Mesoporous microporous Catalysts written by Chuan Wang and published by . This book was released on 2009 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Synthesis and Characterization of Mobil Composition of Material No 41 Mesoporous Silica Supported Palladium nickel Bimetallic Catalysts written by Md. Atikur Rahman and published by . This book was released on 2010 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: Synthesizes noble metals palladium (Pd)-nickel (Ni) nanocatalysts with varying Pd and Ni content using mobil composition of material no. 41 (MCM-41) for hydrogen production from steam reforming of methanol. Carries out the in situ synthesis of silica encapsulated Pd/Ni nanoparticles hydrothermally using template-directed synthesis. Confirms the physico-chemical characteristics of the synthesized MCM-41 support by x-ray diffraction, N2 adsorption, and transmission electron microscopy (TEM) analyses.

Download or read book Catalyst Characterization written by Boris Imelik and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt: to the Fundamental and Applied Catalysis Series Catalysis is important academically and industrially. It plays an essential role in the manufacture of a wide range of products, from gasoline and plastics to fertilizers and herbicides, which would otherwise be unobtainable or prohibitive ly expensive. There are few chemical-or oil-based material items in modern society that do not depend in some way on a catalytic stage in their manufacture. Apart from manufacturing processes, catalysis is finding other important and over-increasing uses; for example, successful applications of catalysis in the control ofpollution and its use in environmental control are certain to in crease in the future. The commercial import an ce of catalysis and the diverse intellectual challenges of catalytic phenomena have stimulated study by a broad spectrum of scientists including chemists, physicists, chemical engineers, and material scientists. Increasing research activity over the years has brought deeper levels of understanding, and these have been associated with a continually growing amount of published material. As recentlyas sixty years ago, Rideal and Taylor could still treat the subject comprehensively in a single volume, but by the 19 50s Emmett required six volumes, and no conventional multivolume text could now cover the whole of catalysis in any depth.

Download or read book Catalytic Conversion of Carbon Monoxide and Methane Over Metal and Metal Oxide Catalysts written by Wenchi Liu and published by . This book was released on 2018 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: Catalysis is of vital importance in a wide range of areas including energy processing and chemical production. Catalytic conversion of C1 sources such as carbon monoxide and methane to make hydrocarbon fuels and oxygenated products has far reaching implications especially in the context of the gradual depletion of crude oil resource and the potential surge in the natural gas production in the coming decades. The control over reaction activity and selectivity for the conversion CO and CH4 in the Fischer–Tropsch synthesis and oxidative coupling of methane (OCM) have received tremendous attention and have been proved challenging. This dissertation focuses on the catalytic conversion of CO (Fischer–Tropsch synthesis) using supported cobalt based bimetallic nanoparticle model catalysts and the oxidative coupling of methane with noble metal promoted metal oxide catalysts. Using colloidal synthesis, a series of cobalt based bimetallic nanoparticles Co–M (M = Mn, Ru, Rh, and Re) with well-defined sizes, shapes, and compositions were obtained. Detailed synthesis procedures were presented and key synthetic parameters were discussed. The as-synthesized nanoparticles were subjected to extensive in-situ X-ray spectroscopy studies using ambient pressure X-ray photoelectron spectroscopy (AP-XPS) and X-ray absorption spectroscopy (XAS) under catalytic relevant conditions. Composition wise, the results indicate the surface concentration of Co on the as-synthesized Co–M bimetallic particles is slightly less than the bulk atomic Co %. While oxidation treatment led to a slight increase of the surface Co, major effect was seen after the reduction treatment where surface segregation of the second metal resulted in a drastic decrease of the surface Co content. The effect is more pronounced at elevated reduction temperatures. Under reaction conditions, the surface compositions remained similar to those after the reduction treatment at high temperatures. Among the bimetallics tested, the Co–Mn system is relatively less susceptible to surface reconstructions induced by oxidation and reduction treatments. In addition, the reducibility of Co was also shown to be modified depending on the second metal present and Re was proved to be most efficient in leading to a facile reduction of Co. Catalytic performance of the bimetallic catalysts supported on mesoporous silica MCF–17 indicates a positive effect in the catalytic activity for Co–Rh and Co–Mn systems, while Co–Re and Co–Cu showed decreased activity. Less pronounced promotion effect of the second metal on the product distribution was observed with only a slight increase in the selectivity towards C5+ products. The selectivities for CH4 and C5+ of the various Co–M bimetallic catalysts generally resemble those of pure Co catalysts. Although in extremely low selectivity, alcohols were also formed with Co–Rh and Co–Cu bimetallic catalysts. The appearance of longer chain alcohol such as propanol, which was not present for pure Co catalysts, is an evidence for potential synergistic promotion. For oxidative coupling of methane (OCM), the promotion effect of noble metals (Pt, Ir, and Rh) on the performance of MnxOy-Na2WO4/MCF–17 catalysts was investigated. The introduction of noble metals had little effect on the surface area and phase composition of the original catalyst but led to a more reduced nature of the surface oxide species. Catalytic study revealed an enhanced selectivity towards both C2 and C3 hydrocarbons as compared to the undoped MnxOy-Na2WO4/MCF–17 catalyst in the order of Rh-doped > Ir-doped > Pt-doped samples together with a lower olefin to paraffin ratio. A more optimized strength of interaction between the carbon intermediates and the catalyst surface was suggested, which in combination with the improved reducibility of Mn and W species are believed to be responsible for the improved performance. In addition, monodispersed leaf-like manganese–tungsten–oxide (Mn–W–Ox) nanoparticles and hydroxylated hexagonal boron nitride (h-BN) were synthesized and used as novel catalysts in OCM reaction. Preliminary results indicate that the MCF–17 supported Mn–W–Ox nanoparticle catalyst showed a CH4 conversion of 5.4% and C2 selectivity of 42% with good stability over time. On the other hand, hydroxylated h-BN exhibited good activity (~20% CH4 conversion) with moderate selectivity towards C2 hydrocarbons (20%–30%). However, the hydroxylated h-BN catalysts faced serious deactivation, which was not eliminated by lowering the reaction temperature or the oxygen concentration in the reaction gas feed.

Download or read book Catalyst Preparation written by John Regalbuto and published by CRC Press. This book was released on 2016-04-19 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text explores the optimization of catalytic materials through traditional and novel methods of catalyst preparation, characterization, and monitoring for oxides, supported metals, zeolites, and heteropolyacids. It focuses on the synthesis of bulk materials and of heterogeneous materials, particularly at the nanoscale. The final chapters examine pretreatment, drying, finishing effects, and future applications involving catalyst preparation and the technological advances necessary for continued progress. Topics also include heat and mass transfer limitations, computation methods for predicting properties, and catalyst monitoring on laboratory and industrial scales.

Download or read book Methane Steam Reforming Activity Stability and Characterization of Nickel Supported Catalysts written by Abdulrhman Saleh al-Ubaid and published by . This book was released on 1984 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Preparation Characterization and Evaluation of Mg Al Mixed Oxide Supported Nickel Catalysts for the Steam Reforming of Ethanol written by Luke James Ivor Coleman and published by . This book was released on 2008 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt: The conversion of ethanol to hydrogen or syngas can be achieved by reacting ethanol with water via steam reforming, CH3CH2OH + (1-x)H2O = (4-x)H2 + (2-x)CO + xCO2 (R.1) CH3CH2OH + H2O = 4H2 + 2CO (R.2) CO + H2O = H2 + CO2 (R.3) Ideally, the ethanol steam reforming reaction can achieve a hydrogen yield of 6 moles of hydrogen per mole of ethanol when the value of x in (R.1) equals 2. High theoretical H2 yield makes ethanol steam reforming a very attractive route for H2 production. Thermodynamic equilibrium studies have shown that ethanol steam reforming produces mixtures of H2, CO, CO2, and CH4 below 950 K, while above 950 K the ethanol steam reforming reaction (R.1) adequately describes the product composition In this study a series of 10wt% Ni loaded Mg-Al mixed oxide supported catalysts were evaluated for the production of hydrogen via the steam reforming of ethanol.

Download or read book Supported Catalysts and Their Applications written by David C Sherrington and published by Royal Society of Chemistry. This book was released on 2007-10-31 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: The need to improve both the efficiency and environmental acceptability of industrial processes is driving the development of heterogeneous catalysts across the chemical industry, including commodity, specialty and fine chemicals and in pharmaceuticals and agrochemicals. Drawing on international research, Supported Catalysts and their Applications discusses aspects of the design, synthesis and application of solid supported reagents and catalysts, including supported reagents for multi-step organic synthesis; selectivity in oxidation catalysis; mesoporous molecular sieve catalysts; and the use of Zeolite Beta in organic reactions. In addition, the two discrete areas of heterogeneous catalysis (inorganic oxide materials and polymer-based catalysts) that were developing in parallel are now shown to be converging, which will be of great benefit to the whole field. Providing a snapshot of the state-of-the-art in this fast-moving field, this book will be welcomed by industrialists and researchers, particularly in the agrochemicals and pharmaceuticals industries.

Download or read book The Catalysis of Uniform Metal Nanoparticles Deposited Onto Oxide Supports written by Nathan Musselwhite and published by . This book was released on 2015 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: Model materials consisting of metal nanoparticles loaded onto oxide supports were synthesized, characterized, and investigated in a number of catalytic chemical reactions. By varying the size, shape, and composition of nanoparticle, as well as the material used to support the nanoparticles, it was found that small changes to the catalyst can have enormous changes to the reaction activity and selectivity. Investigation of these carefully synthesized catalysts via in situ characterization, and reaction studies, leads to a deeper understanding of the molecular level parameters that govern catalysis. Through study of the properties of the nanoparticles it was discovered that nanoparticle size and shape have a dominant role in the chemoselective catalysis of furfural over platinum nanoparticles. When vapor phase furfural and hydrogen gas were passed over Pt nanoparticles ranging in size from 1.5 to 7.1 nm, the catalytic selectivity was found to be dominated by the size of the nanoparticle. Large nanoparticles promoted hydrogenation of furfural to furfuryl alcohol, while smaller nanoparticles favored decarbonylation to furan. The same size specific selectivity was found in the hydrogenative reforming (the transformation of hydrocarbons to branched isomers) of C6 hydrocarbons, in which Pt nanoparticle size controls isomerization selectivity. Methylcyclopentane was found to be extremely size dependent at lower temperatures (553 K). It was found that smaller sized nanoparticles favored isomer formation, while larger sizes catalyzed the aromatization reaction more efficiently. n-hexane was found to be much less dependent on particle size, but still showed an increase in isomerization with small particles over larger sized Pt nanoparticles. The composition of PtxRh1-x bimetallic nanoparticles was also studied. These catalysts were characterized under hexane reforming conditions with Ambient Pressure X-ray Photoelectron Spectroscopy (AP-XPS), in order to find the actual surface atomic composition under real catalytic working conditions. By using AP-XPS and catalytic data in tandem, it was found that an optimum Rh loading occurred when the surface ensemble statistically favored one Rh atom surrounded by Pt atoms. By utilizing different oxide materials for catalytic supports the flow of charge can play a role in the reaction at the surface or interface in a phenomenon known as the strong metal-support interaction (SMSI). When Pt nanoparticles were loaded onto mesoporous supports made of Co3O4, NiO, MnO2, Fe2O3, and CeO2 it was found that their activity for carbon monoxide oxidation was greatly enhanced relative to the support alone or Pt loaded onto inert mesoporous silica. This finding demonstrates that the interface of the metallic Pt nanoparticle and the oxide support is able to produce turnovers that are orders of magnitude higher than the two materials separately. When the same type of experiments were investigated with n-hexane as the reactant and macroporous Al2O3, TiO2, Nb2O5, Ta2O5, and ZrO2 were utilized as supports, it was found that the reaction selectivity was greatly altered depending on the catalytic support material. TiO2, Nb2O5, and Ta2O5 (all of which are strong Lewis acids) were found to be much more selective for isomer production than the standard SiO2 mesoporous silica supported Pt nanoparticle catalyst. Finally, an acidified mesoporous silica material was utilized as the support. This material was synthesized by using AlCl3 to modify the surface of mesoporous silica. This support was found to have no activity for hexane isomerization alone. However, when Pt nanoparticles were supported on the material, the activity and isomer selectivity in hexane reforming was increased several orders of magnitude as compared to the same nanoparticles supported on unmodified mesoporous silica. This dissertation builds on the existing knowledge of known concepts in catalysis science such as structure sensitive reactions, the metal-support interaction, and acid-base chemistry. The results show how small changes in the active sites of a catalyst can create large changes in the catalytic chemistry. This research demonstrates how careful material control, characterization and reaction study can help to elucidate the molecular level components necessary to design efficient catalysts.

Download or read book Studies on Catalytic Reaction of Cardon Dioxide Reforming of Methane Over Supported Nickel Catalysts written by Shaobin Wang and published by . This book was released on 1998 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Catalytic Conversion of Energy Resources into High Value Added Products written by José Luis Pinilla and published by MDPI. This book was released on 2021-09-02 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: Developing active, selective and energy-efficient heterogeneous catalysts is of paramount importance for the production of high value-added products from energy resources in a more sustainable manner. In this Special Issue of Energies, we provide a showcase of the latest progress in the development of cleaner, more efficient processes for the conversion of these feedstocks into valuable fuels, chemicals and energy. Most of the works collected are focused on the conversion of biomass which clearly reflects the paramount importance that the biorefinery concept will play in the years to come.