Journal articles: 'Gas conversion; Synthesis; Metal carbide'

1

Gunawardana, P. V. D. S., John Walmsley, Anders Holmen, De Chen, and Hilde Johnsen Venvik. "Metal Dusting Corrosion Initiation in Conversion of Natural Gas to Synthesis Gas." Energy Procedia 26 (2012): 125–34. http://dx.doi.org/10.1016/j.egypro.2012.06.018.

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Claridge, John B., Andrew P. E. York, Attila J. Brungs, Carlos Marquez-Alvarez, Jeremy Sloan, Shik Chi Tsang, and Malcolm L. H. Green. "New Catalysts for the Conversion of Methane to Synthesis Gas: Molybdenum and Tungsten Carbide." Journal of Catalysis 180, no. 1 (November 1998): 85–100. http://dx.doi.org/10.1006/jcat.1998.2260.

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Won, H. I., H. H. Nersisyan, and C. W. Won. "Combustion synthesis of ultrafine tungsten carbide powder." Journal of Materials Research 23, no. 9 (September 2008): 2393–97. http://dx.doi.org/10.1557/jmr.2008.0289.

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The synthesis of ultrafine tungsten carbide (WC) powder has been investigated from a WO3 + Mg + C mixture via combustion technique. The values of combustion parameters were estimated over the Mg concentration range 3 to 16 mol. Fast increasing tendency of the WC/W2C phase ratio from Mg concentration has been found in the final products. Phase pure WC was prepared with more than 10 mol Mg, and a small amount of ammonium carbonate (or urea) was blended with the WO3+ C mixture. The effects of the combustion conditions on product morphology and composition were evaluated using scanning electron microscopy and x-ray diffraction analysis. The results of the investigation indicate that carbon-containing compounds significantly enhance the combustion synthesis process; leading to higher conversion efficiencies and phase pure WC formation at 1500–1550 °C. The crystalline particles of WC showed a narrow distribution in particle size, with a mean diameter around 200 nm. The results are discussed in the context of gas-phase and solid-phase transport models.

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Wei, Xin. "Synthesis of Alumina-Tungsten Carbide Composites by Self-Propagating High Temperature Synthesis Process." Advanced Materials Research 415-417 (December 2011): 226–31. http://dx.doi.org/10.4028/www.scientific.net/amr.415-417.226.

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Alumina-Tungsten Carbide (Al2O3-WC) composites were synthesized by self-propagating high temperature synthesis (SHS) from a powder mixture of WO3-C-Al. The reaction was carried out in a SHS reactor under static argon gas at a pressure of 0.5 MPa. The standard Gibbs energy minimization method was used to calculate the equilibrium composition of the reacting species. The effects of carbon mole ratio in precursor mixture and diluents of NaCl and Al2O3 on the Al2O3-WC conversion were investigated using X-ray diffraction and scanning electron microscope technique. The as-synthesized products of Al2O3-WC2-WC powders were concurrently formed and the reduction of W2C phase was found when added diluents in precursors.

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GORMLEY, R. "Secondary reactions on metal-zeolite catalysts used in synthesis gas conversion*1." Journal of Catalysis 113, no. 1 (September 1988): 193–205. http://dx.doi.org/10.1016/0021-9517(88)90248-5.

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Lu, Mi, Andrew Lepore, Jae-Soon Choi, Zhenglong Li, Zili Wu, Felipe Polo-Garzon, and Michael Hu. "Acetic Acid/Propionic Acid Conversion on Metal Doped Molybdenum Carbide Catalyst Beads for Catalytic Hot Gas Filtration." Catalysts 8, no. 12 (December 9, 2018): 643. http://dx.doi.org/10.3390/catal8120643.

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Catalytic hot gas filtration (CHGF) is used to precondition biomass derived fast pyrolysis (FP) vapors by physically removing reactive char and alkali particulates and chemically converting reactive oxygenates to species that are more easily upgraded during subsequent catalytic fast pyrolysis (CFP). Carboxylic acids, such as acetic acid and propionic acid, form during biomass fast pyrolysis and are recalcitrant to downstream catalytic vapor upgrading. This work developed and evaluated catalysts that can convert these acids to more upgradeable ketones at the laboratory scale. Selective catalytic conversion of these reactive oxygenates to more easily upgraded compounds can enhance bio-refinery processing economics through catalyst preservation by reduced coking from acid cracking, by preserving carbon efficiency, and through process intensification by coupling particulate removal with partial upgrading. Two metal-doped molybdenum carbide (Mo2C) supported catalyst beads were synthesized and evaluated and their performance compared with an undoped Mo2C control catalyst beads. For laboratory scale acetic acid conversion, calcium doped Mo2C supported catalyst beads produced the highest yield of acetone at ~96% at 450 °C among undoped and Ca or Ni doped catalysts.

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Fontes, F. A. O., K. K. P. Gomes, Francisca de Fatima P. Medeiros, C. P. Souza, J. F. Sousa, and Uilame Umbelino Gomes. "Synthesis of Niobium Carbide from Ammonium Niobium (V) Oxalate Precursor at Low Temperature in Rotating Cylinder Reactor." Materials Science Forum 498-499 (November 2005): 747–0. http://dx.doi.org/10.4028/www.scientific.net/msf.498-499.747.

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The reaction of oxalic precursor {(NH4)3[NbO(C2O4)3]H2O}, was prepared from the Nb2O5, to niobium carbide (NbC) were performed in a rotating cylinder reactor scale-lab designed to niobium carbide powders synthesis at low temperature (1173 K). The NbC was prepared by a oxalic precursor and as well of commercial niobium pentoxide under flowing CH4- H2 mixtures. The reactor was heated through a bi-partied electric furnace with programmable temperature. The reaction overall time was determined from the curve of methane absorption evolution by gas chromatograph (FID) analysis. The preliminary results showed that the conversion function depends on the rotation, temperature, mixture flow, CH4/H2 ratio and heating rate. The niobium carbide was characterized through X-ray diffraction and compared to the commercial products. The reaction of oxalic precursor {(NH4)3[NbO(C2O4)3]H2O} to niobium carbide (NbC) in 3% (v/v) CH4/H2 yielded smallest grain size as well smaller overall time when compared with obtained direct by commercial Nb2O5, however it had small mass conversion due the solid carryover not controlled.

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Kostrin, D. K., and A. A. Lisenkov. "Synthesis of Transition Metals Carbide Compounds in the Vacuum Arc Discharge Plasma." Materials Science Forum 870 (September 2016): 371–76. http://dx.doi.org/10.4028/www.scientific.net/msf.870.371.

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To implement the plasmochemical synthesis of transition metals (Ti, Zr, Mo, W) carbide compounds in a plasma flux of the vacuum arc the discharge carbonaceous working gas is infused. It is shown that the composition of the initial carbonaceous gas defines both the carbon output, and the nature and course of the carbide compounds formation chemical reaction. The composition analysis of the plasma flux in the course of the coating evaporation was carried out by means of the developed emissive spectral analyzer. The result shows that a considerable part of transition metals carbide phases has wide zones of homogeneity within which the change in the carbon content happens without the crystalline grid reorganization. The work reveals and analyzes the factors defining quality of the received carbide compounds (TiC, ZrC, MoC, WC) of refractory metals in a flux of metal plasma of the vacuum arc discharge.

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Jong, K. D. "Electron Microscopy Studies of Supported Metal Catalysts Used for Conversion of Synthesis Gas." Microscopy and Microanalysis 19, S2 (August 2013): 1690–91. http://dx.doi.org/10.1017/s1431927613010441.

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Dorokhov, V. S., D. I. Ishutenko, P. A. Nikul’shin, O. L. Eliseev, N. N. Rozhdestvenskaya, V. M. Kogan, and A. L. Lapidus. "The mechanism of synthesis gas conversion to alcohols catalyzed by transition metal sulfides." Doklady Chemistry 451, no. 1 (July 2013): 191–95. http://dx.doi.org/10.1134/s0012500813070057.

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Guzmán, Héctor J., Wenqian Xu, Dario Stacchiola, Gerardo Vitale, Carlos E. Scott, José A. Rodríguez, and Pedro Pereira-Almao. "In situ time-resolved X-ray diffraction study of the synthesis of Mo2C with different carburization agents." Canadian Journal of Chemistry 91, no. 7 (July 2013): 573–82. http://dx.doi.org/10.1139/cjc-2012-0516.

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Toluene, n-heptane, and methane were studied as carbon sources during the synthesis of Mo2C. Ammonium heptamolybdate ((NH4)6Mo7O24·4H2O), molybdenum dioxide (MoO2), orthorhombic molybdenum trioxide (α-MoO3), and a low crystallinity molybdenum oxide (MoOx) were employed as metal precursors and their conversion into the carbide phase was followed by time-resolved X-ray diffraction from synchrotron radiation. Thermal treatment was carried out from 298 K up to 1023 K and the evolution of gases analyzed by mass spectrometry. The resulting carbidic phase obtained using methane/H2 was hexagonal β-Mo2C, while in contrast, cubic molybdenum carbide (α-MoC1–x) was obtained when toluene/H2 or n-heptane/H2 were employed, which occurred independently of the original metal precursor. Molybdenum carbide was first detected, on average, at about 923 K. Mass spectrometry results show the formation of CO when methane was used as a carbon source, while methyl radicals and benzene and mainly methyl radicals were detected when toluene and n-heptane were employed, respectively.

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Schumann, Julia, Andrew J. Medford, Jong Suk Yoo, Zhi-Jian Zhao, Pallavi Bothra, Ang Cao, Felix Studt, Frank Abild-Pedersen, and Jens K. Nørskov. "Selectivity of Synthesis Gas Conversion to C2+ Oxygenates on fcc(111) Transition-Metal Surfaces." ACS Catalysis 8, no. 4 (March 13, 2018): 3447–53. http://dx.doi.org/10.1021/acscatal.8b00201.

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13

Kirillov, V. A., A. B. Shigarov, N. A. Kuzin, V. V. Kireenkov, A. S. Braiko, and N. V. Burtsev. "Ni/MgO catalysts on structured metal supports for air conversion of lower alkanes to synthesis gas." Kataliz v promyshlennosti 19, no. 5 (September 17, 2019): 351–63. http://dx.doi.org/10.18412/1816-0387-2019-5-351-363.

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A series of thermostable heat-conducting selective catalysts for air conversion of lower alkanes to burn-initiating fuel additives fed as synthesis gas to fuel were developed based on nickel-containing highly porous foam-cellulous material (HPCM) and a net-shaped support. The catalyst synthesis included stages of preparation of the support based on Ni-HPCM (Ni 99,95 %, PPI = 40) or fechral grid, arrangement of the support surface and formation of structured units, thermal treatment of the samples, supporting of the active component via repeated impregnation with a combination of magnesium and nickel acetates, and stepwise thermal treatment. Thus prepared catalysts NiO-MgO/(HPCM or fechral) were tested in the reactions of air conversion of propane, propane-butane, natural gas, as well as tri-reforming. In all the 80–100 hour experiments, the catalysts provided 90–96 % conversion at the flow rate of 32000–71000 h–1, no coke formation being observed at the air excess coefficient of 0.31–0.43. A two-phase two-temperature mathematical model of the air conversion of liquefied hydrocarbon gases (LHG) was developed for the numerical analysis of the results obtained; the modeled results agreed well with the experimental data on temperatures of the catalyst and flow, as well as on the composition of the outlet gas mixture. A generator of 100 kW heat power for the air conversion of LHG was calculated as a practical example.

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Ariyanto, Teguh, Jan Glaesel, Andreas Kern, Gui-Rong Zhang, and Bastian J. M. Etzold. "Improving control of carbide-derived carbon microstructure by immobilization of a transition-metal catalyst within the shell of carbide/carbon core–shell structures." Beilstein Journal of Nanotechnology 10 (February 11, 2019): 419–27. http://dx.doi.org/10.3762/bjnano.10.41.

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Carbon materials for electrical energy devices, such as battery electrodes or fuel-cell catalysts, require the combination of the contradicting properties of graphitic microstructure and porosity. The usage of graphitization catalysts during the synthesis of carbide-derived carbon materials results in materials that combine the required properties, but controlling the microstructure during synthesis remains a challenge. In this work, the controllability of the synthesis route is enhanced by immobilizing the transition-metal graphitization catalyst on a porous carbon shell covering the carbide precursor prior to conversion of the carbide core to carbon. The catalyst loading was varied and the influence on the final material properties was characterized by using physisorption analysis with nitrogen as well as carbon dioxide, X-ray diffraction, temperature-programmed oxidation (TPO), Raman spectroscopy, SEM and TEM. The results showed that this improved route allows one to greatly vary the crystallinity and pore structure of the resulting carbide-derived carbon materials. In this sense, the content of graphitic carbon could be varied from 10–90 wt % as estimated from TPO measurements and resulting in a specific surface area ranging from 1500 to 300 m2·g−1.

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Sano, Hideaki, Hajime Karasuyama, Guo Bin Zheng, and Yasuo Uchiyama. "Kinetics of the SiC Formation from Carbon Thin Film and SiO Gas." Materials Science Forum 510-511 (March 2006): 930–33. http://dx.doi.org/10.4028/www.scientific.net/msf.510-511.930.

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A thin film including β-silicon carbide was synthesized by a reaction of silicon monoxide gas and carbon source derived from polyimide film (PIF) at 1400°, 1500°, 1600°, 1700° and 1800°C. Formation mechanism of the SiC film was investigated thermodynamically and kinetically through the relationships among the conversion ratio of SiC, synthesis temperature and time. The formation processes were simulated based on the calculation of differential equations concerning thermodynamic and kinetic constants of 7 chemical equations. The sample obtained had a film shape similar to that of the carbon source film. The results of the time dependence curves of the conversion ratio of SiC calculated from 7 chemical equations, 14 rate constants, 2 diffusion constants, 10 chemical species and 10 differential equations are in good agreement with the experimental results of the SiC conversion ratio as a function of synthesis time. The calculation results of solving each constant suggest that the formation processes of SiC are "rate-controlled reaction at the interface" at the initial stage of the reaction, and then they gradually change to "diffusion-controlling reaction in the reacted region". In the long term synthesis, we recognized that the waste SiO with non-stoichiometric oxygen can also be used as a silicon source.

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Rivera-Torrente, Miguel, Carlos Hernández Mejía, Thomas Hartman, Krijn P. de Jong, and Bert M. Weckhuysen. "Impact of Niobium in the Metal–Organic Framework-Mediated Synthesis of Co-Based Catalysts for Synthesis Gas Conversion." Catalysis Letters 149, no. 12 (July 13, 2019): 3279–86. http://dx.doi.org/10.1007/s10562-019-02899-0.

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Barthel, Alexander, Youssef Saih, Michel Gimenez, Jérémie D. A. Pelletier, F. E. Kühn, Valerio D'Elia, and Jean-Marie Basset. "Highly integrated CO2capture and conversion: direct synthesis of cyclic carbonates from industrial flue gas." Green Chemistry 18, no. 10 (2016): 3116–23. http://dx.doi.org/10.1039/c5gc03007b.

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The ability of early transition metal halides to capture and convert CO₂from diluted gas flows has been exploited in the cycloaddition of CO₂to epoxides using industrial flue gas as an impure source of CO₂.

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Kim, Jae-Won, Seoung-Soo Lee, Yeon-Gil Jung, Baig-Gyu Choi, Chang-Yong Jo, and Ungyu Paik. "Synthesis of SiC microtube with villus-like morphology and SiC fiber." Journal of Materials Research 20, no. 2 (February 2005): 409–16. http://dx.doi.org/10.1557/jmr.2005.0049.

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Silicon carbide (SiC) microtubes were synthesized and characterized via a vapor–solid (VS) reaction of carbon fiber (Csolid) and SiO(gas). The synthesis mechanisms were investigated. The precursor led complete conversion of [SiO(gas) + C(solid)] into [SiC(solid) + CO(gas)] through overall reaction under inert gas flow at and above 1350 °C. Carbon fibers with small surface area (0.7–2.0 m2 g−1) were gradually converted to SiC microtubes with large specific surface area (45–63 m2 g−1). Inner surface of SiC microtubes indicated a villus-like morphology, which consisted of submicron-sized SiC villi. The outer surface of the SiC microtubes was smooth. Inner surface morphology of SiC microtubes was dependent upon synthesizing temperature. Thickness of villus-like layer in SiC microtubes increased with increasing synthesizing temperature, showing 0.25 and 0.5 at 1350 and 1400 °C, respectively. Both VS and gas–liquid–solid (VLS) growth mechanisms were investigated in synthesis of SiC fiber as a reaction byproduct, and the reaction was governed by both growth mechanisms.

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Patelli, Nicola, Andrea Migliori, Vittorio Morandi, and Luca Pasquini. "One-Step Synthesis of Metal/Oxide Nanocomposites by Gas Phase Condensation." Nanomaterials 9, no. 2 (February 6, 2019): 219. http://dx.doi.org/10.3390/nano9020219.

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Metallic nanoparticles (NPs), either supported on a porous oxide framework or finely dispersed within an oxide matrix, find applications in catalysis, plasmonics, nanomagnetism and energy conversion, among others. The development of synthetic routes that enable to control the morphology, chemical composition, crystal structure and mutual interaction of metallic and oxide phases is necessary in order to tailor the properties of this class of nanomaterials. With this work, we aim at developing a novel method for the synthesis of metal/oxide nanocomposites based on the assembly of NPs formed by gas phase condensation of metal vapors in a He/O2 atmosphere. This new approach relies on the independent evaporation of two metallic precursors with strongly different oxidation enthalpies. Our goal is to show that the precursor with less negative enthalpy gives birth to metallic NPs, while the other to oxide NPs. The selected case study for this work is the synthesis of a Fe-Co/TiOx nanocomposite, a system of great interest for its catalytic and magnetic properties. By exploiting the new concept, we achieve the desired target, i.e., a nanoscale dispersion of metallic alloy NPs within titanium oxide NPs, the structure of which can be tailored into TiO1- or TiO2 by controlling the synthesis and processing atmosphere. The proposed synthesis technique is versatile and scalable for the production of many NPs-assembled metal/oxide nanocomposites.

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Kuzmichev, E. N., S. V. Nikolenko, and P. G. Chigrin. "Preparation of Tungsten Based Metal-Ceramic Alloys by the Plasma Chemical Synthesis from the Mineral Concentrate Mined in the Far Eastern Region." Materials Science Forum 992 (May 2020): 809–13. http://dx.doi.org/10.4028/www.scientific.net/msf.992.809.

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s The paper considers the development of an alternative method for obtaining functional materials based on tungsten carbide and its compounds using simple and sufficiently productive equipment. This method will allow using mineral dumps as a raw material base, in addition, it gives an opportunity to obtain new compounds based on tungsten. Obtained during plasma-chemical synthesis, the WxCW alloy from a mixture based on a tungsten-containing concentrate has a two-phase composition consisting of carbides of the WxCW group and metallic tungsten. According to preliminary calculations, the content of the carbide phase in the alloy is 88% and depends on the plasma synthesis processes, on the concentrate composition, and on the introduced carburetor volume. The synthesis was carried out using tungsten-containing concentrates by treatment of high-density energies (g> 104 - 105 W/cm2) in an inert gas medium. The stage of plasma-chemical synthesis of the WxCW semi-finished product made it possible to obtain nanosized tungsten carbide crystals. This makes a possibility to synthesize a high-quality alloy with an ordered structure of the carbide phase during refinement and pressing. The carbide phase ordered structure contributed to an increase in the strength characteristics of the new refractory material.

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Gotti, A., and R. Prins. "Basic Metal Oxides as Cocatalysts for Cu/SiO2Catalysts in the Conversion of Synthesis Gas to Methanol." Journal of Catalysis 178, no. 2 (September 1998): 511–19. http://dx.doi.org/10.1006/jcat.1998.2167.

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22

Lima, Maria Jose S., M. V. M. Souto, A. S. Souza, M. M. Karimi, F. E. S. Silva, Uilame Umbelino Gomes, and Carlson P. de Souza. "Synthesis of Nanostructured Tungsten Carbide (WC) from Ammonia Paratungstate-APT and its Characterization by XRD and Rietveld Refinement." Materials Science Forum 899 (July 2017): 31–35. http://dx.doi.org/10.4028/www.scientific.net/msf.899.31.

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The carbides of refractory metals like tungsten carbide (WC), tantalum carbide (TaC) and niobium carbide (NbC), has been extensively studied due to their applications in several areas of industry, because of their specific properties; such as high melting point, high hardness, wear resistance, oxidation resistance and good electrical conductivity. The tungsten carbide, particularly, is generally used at hardmetal industries due to its high hardness and wear resistance. New synthesis techniques have been developed to reduce the synthesis temperature of refractory metal carbides using more reactive precursors and gas-solid reactions for carbon reduction. The result is producing pure carbides suitable properties for production of high quality cemented carbides and more selective catalysts. In this work, pure and nanostructured WC was obtained from the ammonium paratungstate hydrate (APT), at low temperature and short reaction time. Hydrogen (H2) and methane (CH4) were used as a reducing gas and carbon source, respectively. The precursor and obtained product were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results obtained by diffraction of X-rays showed that complete reduction and carburization of APT have been took place resulted in pure WC formation. The average crystallite size was in nanometer order reaching values of approximately 20.8 nm and a surface area (BET) of 26.9 m2/g.

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Oschatz, M., S. Krause, N. A. Krans, C. Hernández Mejía, S. Kaskel, and K. P. de Jong. "Influence of precursor porosity on sodium and sulfur promoted iron/carbon Fischer–Tropsch catalysts derived from metal–organic frameworks." Chemical Communications 53, no. 73 (2017): 10204–7. http://dx.doi.org/10.1039/c7cc04877g.

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Bordoloi, Ankur, Johan Anton, Holger Ruland, Martin Muhler, and Stefan Kaluza. "Metal–support interactions in surface-modified Cu–Co catalysts applied in higher alcohol synthesis." Catalysis Science & Technology 5, no. 7 (2015): 3603–12. http://dx.doi.org/10.1039/c5cy00421g.

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Cu–Co-based model catalysts were prepared by a sophisticated alkali-free synthesis method and tested in the conversion of synthesis gas to higher alcohols. MoO₃-coated alumina was used as the support, providing both high specific surface area and strongly interacting sites for the deposition of the active metals.

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Sivaji, Karna, and Gandham Phanikumar. "Microstructure and Precipitation Studies of Gas Tungsten Arc Welded Haynes 282 Superalloy." Materials Science Forum 1016 (January 2021): 666–71. http://dx.doi.org/10.4028/www.scientific.net/msf.1016.666.

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Improvement in efficiency of energy conversion requires the use of high temperature materials in thermal power plants. This has led to the development of new γ' strengthened nickel based superalloy (Haynes 282). This alloy is used for advanced ultra-supercritical (AUSC) plants which are operated under the service conditions of 760 oC temperature and 35 MPa pressure. Bead on plate gas tungsten arc welding experiments were done with optimized process parameters. Thermal cycle in heat affected zone was measured by K-type thermocouple attached to a data acquisition system. Welding simulations were carried out in simufact welding® by using experimental parameters and thermal field was established. Base metal is characterized with γ solid solution and randomly distributed MC carbides. SEM results showed that the carbides are of MC type. The carbide precipitate distribution correlates with the segregation pattern during solidification of the weld.

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Kirillov, V. A., A. S. Bobrin, N. A. Kuzin, V. A. Kuzmin, A. B. Shigarov, V. B. Skomorokhov, E. I. Smirnov, and V. A. Sobyanin. "Compact Radial Reactor with a Structured Porous Metal Catalyst for the Conversion of Natural Gas to Synthesis Gas: Experiment and Modeling." Industrial & Engineering Chemistry Research 43, no. 16 (August 2004): 4721–31. http://dx.doi.org/10.1021/ie030785s.

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Kirillov, V. A., A. B. Shigarov, N. A. Kuzin, V. V. Kireenkov, A. S. Brayko, and N. V. Burtsev. "Ni/MgO Catalysts on Structured Metal Supports for the Air Conversion of Low Alkanes into Synthesis Gas." Catalysis in Industry 12, no. 1 (January 2020): 66–76. http://dx.doi.org/10.1134/s2070050420010080.

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Salim, Sharifah Aishah Syed, Julie Juliewatty Mohamed, Zainal Arifin Ahmad, and Zainal Arifin Ahmad. "Effect of Nickel on Titanium Carbide Synthesized via Tungsten Inert Gas (TIG) Method." Advanced Materials Research 620 (December 2012): 384–88. http://dx.doi.org/10.4028/www.scientific.net/amr.620.384.

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Numerous methods have been used to produce high purity TiC. There is no previous study has been reported on the formation using single elemental powders of Titanium (Ti) and Carbon (C) with addition Nickel (Ni) by tungsten inert gas (TIG) weld method. In this work, TiC was synthesized via TIG method by arc melting elemental powder mixture of Ti and C at ~5 second (s) and 80 ampere (A). The effect Ni contents on TiC formation was investigated. The mixed raw material was ball milled for 24 hours followed by synthesis via TIG method. The arced samples were characterized by X-ray diffraction (XRD) and Scanning electron microscope (SEM). It was revealed, that small amount of Ni additive to the metal powder allows the production of dense and tough TiC.

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Chen, Jian, He Li, Mingmei Zhong, and Qihua Yang. "Hierarchical mesoporous organic polymer with an intercalated metal complex for the efficient synthesis of cyclic carbonates from flue gas." Green Chemistry 18, no. 24 (2016): 6493–500. http://dx.doi.org/10.1039/c6gc02367c.

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Direct conversion of flue gas and epoxides to cyclocarbonates has been shown, using a 2,2-bipyridine Zn(ii) based hierarchical meso/microporous polymer as a catalyst. Mesopores facilitate reactant diffusion, while micropores enhance CO₂ enrichment.

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30

Gotti, A., and R. Prins. "Basic Metal Oxides as Co-Catalysts in the Conversion of Synthesis Gas to Methanol on Supported Palladium Catalysts." Journal of Catalysis 175, no. 2 (April 1998): 302–11. http://dx.doi.org/10.1006/jcat.1998.1996.

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31

Schmitt, Sophia, Sergey Shishatskiy, Peter Krolla, Qi An, Salma Begum, Alexander Welle, Tawheed Hashem, et al. "Synthesis, Transfer, and Gas Separation Characteristics of MOF-Templated Polymer Membranes." Membranes 9, no. 10 (September 20, 2019): 124. http://dx.doi.org/10.3390/membranes9100124.

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This paper discusses the potential of polymer networks, templated by crystalline metal–organic framework (MOF), as novel selective layer material in thin film composite membranes. The ability to create mechanically stable membranes with an ultra-thin selective layer of advanced polymer materials is highly desirable in membrane technology. Here, we describe a novel polymeric membrane, which is synthesized via the conversion of a surface anchored metal–organic framework (SURMOF) into a surface anchored gel (SURGEL). The SURGEL membranes combine the high variability in the building blocks and the possibility to control the network topology and membrane thickness of the SURMOF synthesis with high mechanical and chemical stability of polymers. Next to the material design, the transfer of membranes to suitable supports is also usually a challenging task, due to the fragile nature of the ultra-thin films. To overcome this issue, we utilized a porous support on top of the membrane, which is mechanically stable enough to allow for the easy membrane transfer from the synthesis substrate to the final membrane support. To demonstrate the potential for gas separation of the synthesized SURGEL membranes, as well as the suitability of the transfer method, we determined the permeance for eight gases with different kinetic diameters.

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Zainul Anwar, Muchammad, Rachmat Triandi Tjahjanto, and Uswantun Hasanah. "Synthesis and Activation Study of Iron (Fe) Based Fischer Tropsch (FT) Catalyst Using Sol-gel Method." Journal of Pure and Applied Chemistry Research 8, no. 3 (December 1, 2019): 217–24. http://dx.doi.org/10.21776/ub.jpacr.2019.008.03.480.

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As oil consumption increases from year to year, efforts need to be made to increase energy reserves by developing new renewable energy. One way to develop energy sources is by the synthesis Fischer Tropsch (FT). FT is a synthetic gas conversion reaction (mixture of CO and H2) into a long chain hydrocarbon mixture. The FT reaction requires a catalyst called the FT catalyst. So far, many studies that examine the effectiveness of catalysts in converting synthesis gas into long chain hydrocarbons, but rarely information about the composition of the phases that exist on the surface of the catalyst. To study about it, we synthesized FT catalysts at various variations of calcination temperature. Fe(NO3)3 as a precursor and Cu(NO3)2 as promoter (20:1) used in this study. The calcination temperature used are 300, 500, and 700°C. Characterization and analysis of catalysts were formed with XRD and SEM-EDX. Calcined catalysts were activated using CO2 and H2 gas and then re-characterized with XRD and SEM-EDX. Calcination results the formation of an iron oxide phase, while activation results the formation of iron carbide and zero Fe phases.

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Kim, Ki-Hwan, Emmanuel Lefeveure, Marc Châtelet, and Costel-Sorin Cojocaru. "Porous Alumina Template based Versatile and Controllable Direct Synthesis of Silicon nanowires." MRS Proceedings 1439 (2012): 11–16. http://dx.doi.org/10.1557/opl.2012.940.

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ABSTRACTHighly densely packed, self-organized silicon nanowires with very narrow diameter distribution were synthesized within porous anodic alumina templates with electrodeposited catalytic metal nanoparticles. For successful catalytic metal nanoparticle deposition, electrochemical-, and chemical barrier layer thinning process was investigated following anodization process. Controlled pulsed electrodeposition process was carried out for a volume calibration of desired catalytic metal nanoparticle deposition inside nanopore arrays using different metal-ion containing electrolyte. Not only single metal nanoparticles, but also multi metal nanoparticles layers were filled inside PAA to enhance metal filling aspect, and to control the volume of nanoparticles more precisely. Using multilayered metal nanoparticles resulted on different SiNW’s growth behavior depending on the types of underlying metal nanoparticles.SiNWs were successfully synthesized using hot-filament assisted chemical vapor deposition system. Although silicon precursor gas can generally be dissociated at relatively low temperatures, the use of a hot filament activation help decreasing process temperature, and also, highly activated atomic hydrogen generation via the tungsten hot filament placed at gas inlet helps preventing parasitic amorphous silicon deposition on either the alumina membrane surface or the pore wall which hinders appropriate growth of SiNWs in PAA by nanopores clogging. Such densely packed, self-organized SiNWs are of high interest in many application fields like nanoelectronics, optoelectronics, and energy storage/conversion devices etc.

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Akhanova, Nazym Yerlanovna, Dmitry Viktorovich Shchur, Anatoly Petrovich Pomytkin, Alexander Dmitrievich Zolotarenko, Anatoly Dmitrievich Zolotarenko, Natalia Afanasievna Gavrylyuk, Marzhan Ualkhanova, Wang Bo, and Ding Ang. "Methods for the Synthesis of Endohedral Fullerenes." Journal of Nanoscience and Nanotechnology 21, no. 4 (April 1, 2021): 2446–59. http://dx.doi.org/10.1166/jnn.2021.18971.

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In the present manuscript the authors show the progress recorded regarding the main synthesis methods of metal endo-fullerenes. Shown, that nowadays, the most productive and common method of producing endohedral fullerenes is the electric arc process due to the fact that (a) it is simple enough to introduce atoms into the plasma from solids and gases; (b) its performance is the highest among other methods; (c) gives a wide range of produced types of metallofullerenes in an inert atmosphere-mono-, di-, tri-metalfullerenes, metal carbide clusters, in a reactive atmosphere (N2, NH3)-metal nitride and cyanide clusters, heterofullerenes; (d) provides the greatest energy potential, which is likely to allow the introduction into the cells of fullerene molecules metal atoms with higher ionization energies than titanium (≥7 eV). The yield of metal endofullerenes is substantially higher than the “empty” fullerenes. In this case, the stabilization of both metal atoms and fullerene cells occurs. The quantitative and qualitative output of MEF is significantly affected by: (a) conditions of the process in the reactor: the gas pressure, its flow rate, temperature, amperage; the distance between the electrodes, and others, that is, those factors that determine the plasma temperature and the residence time of the reaction particles in it; (b) the composition of solid additives (salts, oxides, metal alloys) in the graphite anode and their quantitative (mol) ratio with carbon; (c) replacement of the inert atmosphere of the synthesis with the active one (helium-with nitrogen, ammonia, water vapor, CO and other gases).

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Kondratenko, V. A., U. Karimova, A. A. Kasimov, and E. V. Kondratenko. "Methane conversion into synthesis gas over supported well-defined Pt, Rh or Ru nanoparticles: Effects of metal and support." Applied Catalysis A: General 619 (June 2021): 118143. http://dx.doi.org/10.1016/j.apcata.2021.118143.

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Pour, Ali Nakhaei, and Seyed Majed Modaresi. "Methane Formation in Fischer-Tropsch Synthesis: Role of Nanosized Catalyst Particles." Journal of Nano Research 35 (October 2015): 39–54. http://dx.doi.org/10.4028/www.scientific.net/jnanor.35.39.

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Concepts of the surface excess energy in the present work have been applied to explain the methane formation in Fischer-Tropsch synthesis by iron catalysts. A series of iron oxide particles doped by adding copper and lanthanum were prepared as a catalyst via precipitation by microemulsion method. Size dependent kinetic expressions for methane formation were derived and evaluated using experimental results. Experimental results show that the methane formation is increased by decreasing the catalyst particle size. The value of surface tension energy (σ) for iron catalyst is calculated in range of 0.047-0.015 J/m2in methane formation mechanism. This value is lower than iron metal and is referred to the presence of iron carbide and gas phase in this catalytic reaction. With a series of complicated mechanisms, methane is produced on the surface of catalyst and in the gas phase as well, this would be elaborated by following paragraphs, thus we can conclude that surface tension of catalyst has less effect on these reactions.

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Storr, Bria, Deepa Kodali, Kallol Chakrabarty, Paul A. Baker, Vijaya Rangari, and Shane A. Catledge. "Single-Step Synthesis Process for High-Entropy Transition Metal Boride Powders Using Microwave Plasma." Ceramics 4, no. 2 (May 28, 2021): 257–64. http://dx.doi.org/10.3390/ceramics4020020.

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A novel approach is demonstrated for the synthesis of the high entropy transition metal boride (Ta, Mo, Hf, Zr, Ti)B2 using a single heating step enabled by microwave-induced plasma. The argon-rich plasma allows rapid boro-carbothermal reduction of a consolidated powder mixture containing the five metal oxides, blended with graphite and boron carbide (B4C) as reducing agents. For plasma exposure as low as 1800 °C for 1 h, a single-phase hexagonal AlB2-type structure forms, with an average particle size of 165 nm and with uniform distribution of the five metal cations in the microstructure. In contrast to primarily convection-based (e.g., vacuum furnace) methods that typically require a thermal reduction step followed by conversion to the single high-entropy phase at elevated temperature, the microwave approach enables rapid heating rates and reduced processing time in a single heating step. The high-entropy phase purity improves significantly with the increasing of the ball milling time of the oxide precursors from two to eight hours. However, further improvement in phase purity was not observed as a result of increasing the microwave processing temperature from 1800 to 2000 °C (for fixed ball milling time). The benefits of microwave plasma heating, in terms of allowing the combination of boro-carbothermal reduction and high entropy single-phase formation in a single heating step, are expected to accelerate progress in the field of high entropy ceramic materials.

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Krutskii, Yu L., T. S. Gudyma, K. D. Dyukova, R. I. Kuz’min, and T. M. Krutskaya. "Diborides of transition metals: Properties, application and production. review. Part 2. Chromium and zirconium diborides." Izvestiya. Ferrous Metallurgy 64, no. 6 (July 21, 2021): 395–412. http://dx.doi.org/10.17073/0368-0797-2021-6-395-412.

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The second part of the review considers properties, application and methods for producing chromium and zirconium diborides. These diborides are oxygen-free refractory metal-like compounds. As a result, they are characterized by high values of thermal and electrical conductivity. Their hardness is relatively high. Chromium and zirconium diborides exhibit significant chemical resistance in aggressive environments. They have found application in modern technology because of these reasons. Chromium diboride is used as a sintering additive to improve the properties of ceramics based on boron carbide and titanium diboride. Zirconium diboride is a component of advanced ultra-high temperature ceramics (UHTC) ZrB2 –SiC used in supersonic aircrafts and in gas turbine assemblies. Ceramics B4C–CrB2 and B4C–ZrB2 have high-quality performance characteristics, in particular, increased crack resistance. The properties of refractory compounds depend on the content of impurities and dispersion. Therefore, to solve a specific problem associated with the use of refractory compounds, it is important to choose the method of their preparation correctly, to determine the admissible content of impurities in the starting components. This leads to the presence of different methods for the borides synthesis. The main methods for their preparation are: a) synthesis from elements; b) borothermal reduction of oxides; c) carbothermal reduction (reduction of mixtures of metal oxides and boron with carbon; d) metallothermal reduction of metal oxides and boron mixtures; e) boron-carbide reduction. Plasma-chemical synthesis (deposition from the vapor-gas phase) is also used to obtain diboride nanopowders. Each of these methods is described.

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Собачкин, Алексей, Aleksey Sobachki, Александр Ситников, Alexandr Sitnikov, Владимир Яковлев, Vladimir Yakovlev, Марина Логинова, et al. "Gas-detonation sputtering of piston ring coatings for internal combustion engines by SVS-mechanocomposites based on titanium carbide." Science intensive technologies in mechanical engineering 2018, no. 6 (May 30, 2018): 31–37. http://dx.doi.org/10.30987/article_5b0e41129735e8.77479450.

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There are considered ecologically harmless technologies for nano-structural material obtaining by methods of mechanochemistry with carrying out a reaction of high-temperature synthesis in a metal matrix for the application of the powder material obtained in the course of gas-detonation coating processes which may substitute electroplate chromium coating. As a sputtered powder there was used SVS- mechanocomposite having Ti-C-NiCr in its composition. It is determined that the wear of piston rings with the developed coating is lower by 27%, than in similar rings with an electroplate chromium coating.

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Shishkova, M. L., and N. V. Yakovleva. "Catalytically active coatings for steam reforming systems: synthesis and catalytic properties." Voprosy Materialovedeniya, no. 2(94) (January 10, 2019): 96–105. http://dx.doi.org/10.22349/1994-6716-2018-94-2-96-105.

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The paper considers science and engineering aspects of catalytically active compositions creation as regards immobilized catalysts for reforming hydrocarbon raw materials into hydrogen fuel. The authors investigate synthesis of catalytic powder mixtures and manufacturing of functional coatings by supersonic cold gas dynamic spraying. Research results in the field of creation of catalysts for steam conversion of methane to hydrogenous fuel on the metal support (Cr15Al15 tape support) are given. Composite powder mixtures (Ni–Al–Al(OH)3– Ca(OH)2–Mg(OH)2) were used as starting materials.

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Kim, Tae Young, Seong Bin Jo, Jin Hyeok Woo, Jong Heon Lee, Ragupathy Dhanusuraman, Soo Chool Lee, and Jae Chang Kim. "Investigation of Co–Fe–Al Catalysts for High-Calorific Synthetic Natural Gas Production: Pilot-Scale Synthesis of Catalysts." Catalysts 11, no. 1 (January 13, 2021): 105. http://dx.doi.org/10.3390/catal11010105.

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Co–Fe–Al catalysts prepared using coprecipitation at laboratory scale were investigated and extended to pilot scale for high-calorific synthetic natural gas. The Co–Fe–Al catalysts with different metal loadings were analyzed using BET, XRD, H2-TPR, and FT-IR. An increase in the metal loading of the Co–Fe–Al catalysts showed low spinel phase ratio, leading to an improvement in reducibility. Among the catalysts, 40CFAl catalyst prepared at laboratory scale afforded the highest C2–C4 hydrocarbon time yield, and this catalyst was successfully reproduced at the pilot scale. The pelletized catalyst prepared at pilot scale showed high CO conversion (87.6%), high light hydrocarbon selectivity (CH4 59.3% and C2–C4 18.8%), and low byproduct amounts (C5+: 4.1% and CO2: 17.8%) under optimum conditions (space velocity: 4000 mL/g/h, 350 °C, and 20 bar).

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Shohoji, Nobumitsu, Fernando A. Costa Oliveira, Luis Guerra Rosa, José Cruz Fernandes, Teresa Magalhães, Manuel Caldeira Coelho, José Rodríguez, Inmaculada Cañadas, Carlos Ramos, and Diego Martínez. "Synthesising Carbo-Nitrides of some D-Group Transition Metals Using a Solar Furnace at PSA." Materials Science Forum 730-732 (November 2012): 153–58. http://dx.doi.org/10.4028/www.scientific.net/msf.730-732.153.

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Carbo-nitride synthesis was undertaken using a solar furnace at PSA in flowing N2/Ar gas mixture under total pressure 1 atm and processing temperatureT= 1600°C for some d-group transition elements (Ti; Zr, V, Nb, Mo, W) starting from 1.5G/M (graphite/metal powder mixture with mole ratio 1.5:1) compact to ensure co-presence of free carbon with the reaction product. Clear X-ray diffraction (XRD) evidence of formation of carbo-nitride was detected for Ti (IVa group metal) showing higher N content in the carbo-nitride synthesised in N2gas environment at partial pressurep(N2) = 1 atm than that atp(N2) = 0.5 atm. For M = V and Nb (Va group metals), formation of mono-carbide MC single-phase was detected in the N2environment showing no evidence of formation of carbo-nitride in spite of presence of N2in the environment. For M = Mo and W (VIa group metals), formation of higher carbide, among several options of carbide phases, appeared to be promoted in the N2gas environment although, like in cases with the Va group metals, no evidence of dissolution of N into the reaction product was detected. As such, atT= 1600°C in N2gas environment up top(N2) = 1 atm under concentrated solar beam, carbo-nitride formed from the 1.5G/M mixture only for IVa group metal (Ti) but not for Va and VIa group metals. Anyway, it seemed certain that N2gas affected somehow the reaction path between G and M to yield the carbide phase for M = V, Nb, Mo and W.

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Fan, Xiaoyuan, Peng Du, Xiaoxuan Ma, Ruyue Wang, Jingteng Ma, Yonggang Wang, Dongyu Fan, et al. "Mechanochemical Synthesis of Pt/Nb2CTx MXene Composites for Enhanced Electrocatalytic Hydrogen Evolution." Materials 14, no. 9 (May 6, 2021): 2426. http://dx.doi.org/10.3390/ma14092426.

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Production of hydrogen from water splitting has been considered as a promising solution for energy conversion and storage. Since a noble metal-based structure is still the most satisfactory but scarce kind of catalyst, it is significant to allow for practical application of such catalysts by engineering the heterogeneous structure and developing green and facile synthetic strategies. Herein, we report a mechanochemical ball milling synthesis of platinum nanoclusters immobilized on a 2D transition metal carbide MXene (Nb2CTx) as an enhanced catalyst for hydrogen evolution. After annealing at 600 °C, ultrafine Pt3Nb nanoclusters are formed on the Pt/Nb2CTx catalyst. As prepared, the Pt/Nb2CTx-600 catalyst demonstrates superior electrochemical HER activity and stability with an ultralow overpotential of 5 mV and 46 mV to achieve 10 mA cm−2 and 100 mA cm−2, respectively, in comparison with other Nb2CTx-based catalysts and commercial Pt/C catalysts. Moreover, the remarkable durability is also confirmed by accelerated durability tests (ADTs) and long-term chronoamperometry (CA) tests. The excellent HER performance was attributed to high Pt dispersion and more active site exposure by the mechanochemical process and thermal treatment. Such results suggest that the mechanochemical strategy provides a novel approach for rational design and cost-effective production of electrocatalysts, also providing other potential applications in a wide range of areas.

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Karim, Muhammad Arief, Heni Juniar, and M. Fitria Putri Ambarsari. "ADSORPSI ION LOGAM Fe DALAM LIMBAH TEKSTIL SINTESIS DENGAN MENGGUNAKAN METODE BATCH." Jurnal Distilasi 2, no. 2 (November 5, 2018): 68. http://dx.doi.org/10.32502/jd.v2i2.1205.

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Adsorption is a process occurs in a fluid, either it is liquid or gas, bonded in a solid or liquid (absorbent agent, adsorbent) and eventually creates a thin layer or film (adsorbed agent, adsorbent) on its surface. In this study, the writer did the process of the adsorption of Fe metal ion to the adsorbent of carbide waste that has been processed into tablet with 3x5 mm size, adsorption was done with Batch process by stirring 15gr or adsorbent into 100ml of synthetic waste with 50rpm stirring speed. There are two factors that influence the decrease of Fe metal concentration in synthesis waste which is the influence of pH and time. This study used variables of adsorption time (1; 2; 3; 4; 5; 6) hours with pH (2.5; 4.1) for each hour with an initial concentration of Fe 800g metal ions. This study was conducted to obtain the optimum value of pH and concentration of final Fe metal ions with the comparison of initial pH ratio and predetermined time. Seen from the matrix results of the study, it can be concluded that the longer the stirring time the more metal ions are absorbed by the adsorbent of carbide waste and pH value also rises.

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Panda, Atanu, Euisoo Kim, Yong Choi, Jihyun Lee, Sada Venkateswarlu, and Minyoung Yoon. "Phase Controlled Synthesis of Pt Doped Co Nanoparticle Composites Using a Metal-Organic Framework for Fischer–Tropsch Catalysis." Catalysts 9, no. 2 (February 5, 2019): 156. http://dx.doi.org/10.3390/catal9020156.

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Recently, metal nanoparticles embedded in porous carbon composite materials have been playing a significant role in a variety of fields as catalyst supports, sensors, absorbents, and in energy storage. Porous carbon composite materials can be prepared using various synthetic methods; recent efforts provide a facile way to prepare the composites from metal-organic frameworks (MOFs) by pyrolysis. However, it is usually difficult to control the phase of metal or metal oxides during the synthetic process. Among many types of MOF, recently, cobalt-based MOFs have attracted attention due to their unique catalytic and magnetic properties. Herein, we report the synthesis of a Pt doped cobalt based MOF, which is subsequently converted into cobalt nanoparticle-embedded porous carbon composites (Pt@Co/C) via pyrolysis. Interestingly, the phase of the cobalt metal nanoparticles (face centered cubic (FCC) or hexagonal closest packing (HCP)) can be controlled by tuning the synthetic conditions, including the temperature, duration time, and dosage of the reducing agent (NaBH4). The Pt doped Co/C was characterized using various techniques including PXRD (powder X-ray diffraction), XPS (X-ray photoelectron spectroscopy), gas sorption analysis, TEM (transmission electron microscopy), and SEM (scanning electron microscopy). The composite was applied as a phase transfer catalyst (PTC). The Fischer-Tropsch catalytic activity of the Pt@Co/C (10:1:2.4) composite shows 35% CO conversion under a very low pressure of syngas (1 MPa). This is one of the best reported conversion rates at low pressure. The 35% CO conversion leads to the generation of various hydrocarbons (C1, C2–C4, C5, and waxes). This catalyst may also prove useful for energy and environmental applications.

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Akopdzhanyan, T. G., E. A. Chemagina, and I. P. Borovinskaya. "Study into the feasibility of obtaining dense materials based on AlN-SiC solid solution in one stage by SHS gasostatiс processing." Izvestiya vuzov. Poroshkovaya metallurgiya i funktsional’nye pokrytiya, no. 3 (November 16, 2020): 34–40. http://dx.doi.org/10.17073/1997-308x-2020-3-34-40.

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The synthesis and sintering of the (AlN)x(SiC)1–x solid solution were studied under the conditions of SHS gasostatiс processing at high nitrogen gas pressures (up to 110 MPa). Phase formation during the combustion of aluminum and silicon carbide mixtures with the different amount of a combustible component (aluminum content is 35 to 60 wt.%) was studied. It was shown that the optimal amount of aluminum mixed with silicon carbide to obtain a single-phase solid solution (with the complete Al conversion to AlN and without SiC dissociation) is 45–50 wt.%. A mixture with 55–60 wt.% Al leads to excessively high temperatures, which in turn leads to the silicon carbide decomposition to Si + C elements. The optimal parameters for obtaining a dense material in one stage were determined. The measured porosity and density of materials obtained demonstrated that preforming is essential for the final density of samples containing 50 wt.% Al: maximum density was achieved at a preforming pressure of 10 MPa. It was found that the 5 wt.% yttrium oxide additive increases the material density by almost 10 %. A similar effect is also obtained by increasing the initial gas pressure from 80 to 110 MPa. The maximum density in this case reached 2.7 g/cm3, i.e. 83 % of the theoretical density. The total volumetric shrinkage of the material was 10 ± 0.5 %, and this indicator can be almost completely smoothed over by the 3 wt.% boron additive. The microhardness of samples was 2000 kg/mm2.

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Kim, Kyoung-Jin, Yeol-Lim Lee, Hyun-Suk Na, Seon-Yong Ahn, Jae-Oh Shim, Byong-Hun Jeon, and Hyun-Seog Roh. "Efficient Waste to Energy Conversion Based on Co-CeO2 Catalyzed Water-Gas Shift Reaction." Catalysts 10, no. 4 (April 12, 2020): 420. http://dx.doi.org/10.3390/catal10040420.

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Waste to energy technology is attracting attention to overcome the upcoming environmental and energy issues. One of the key-steps is the water-gas shift (WGS) reaction, which can convert the waste-derived synthesis gas (H2 and CO) to pure hydrogen. Co–CeO2 catalysts were synthesized by the different methods to derive the optimal synthetic method and to investigate the effect of the preparation method on the physicochemical characteristics of Co–CeO2 catalysts in the high-temperature water-gas shift (HTS) reaction. The Co–CeO2 catalyst synthesized by the sol-gel method featured a strong metal to support interaction and the largest number of oxygen vacancies compared to other catalysts, which affects the catalytic activity. As a result, the Co–CeO2 catalyst synthesized by the sol-gel method exhibited the highest WGS activity among the prepared catalysts, even in severe conditions (high CO concentration: ~38% in dry basis and high gas hourly space velocity: 143,000 h−1).

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Cui, Yan, Xinbo Lian, Leilei Xu, Mindong Chen, Bo Yang, Cai-e. Wu, Wenjing Li, Bingbo Huang, and Xun Hu. "Designing and Fabricating Ordered Mesoporous Metal Oxides for CO2 Catalytic Conversion: A Review and Prospect." Materials 12, no. 2 (January 16, 2019): 276. http://dx.doi.org/10.3390/ma12020276.

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In the past two decades, great progress has been made in the aspects of fabrication and application of ordered mesoporous metal oxides. Ordered mesoporous metal oxides have attracted more and more attention due to their large surface areas and pore volumes, unblocked pore structure, and good thermal stabilities. Compared with non-porous metal oxides, the most prominent feature is their ability to interact with molecules not only on their outer surface but also on the large internal surfaces of the material, providing more accessible active sites for the reactants. This review carefully describes the characteristics, classification and synthesis of ordered mesoporous metal oxides in detail. Besides, it also summarizes the catalytic application of ordered mesoporous metal oxides in the field of carbon dioxide conversion and resource utilization, which provides prospective viewpoints to reduce the emission of greenhouse gas and the inhibition of global warming. Although the scope of current review is mainly limited to the ordered mesoporous metal oxides and their application in the field of CO2 catalytic conversion via heterogeneous catalysis processes, we believe that it will provide new insights and viewpoints to the further development of heterogeneous catalytic materials.

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Pfeifer, Mirko, Thomas Schwarz, Pengfei Cao, and Klaus Stöwe. "Reaction Analyses Based on Quaternary Metal/Metal Oxide Catalyst Testing in Micro-Structured Reactors Using Combinatorial High-Throughput Methods for Power-to-Gas Applications." Catalysts 11, no. 1 (December 23, 2020): 6. http://dx.doi.org/10.3390/catal11010006.

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To optimize the Sabatier process, quaternary supported catalyst materials are synthesized and tested. The syntheses are performed by the industrially established, reproducible and automated methods of impregnation and sol–gel synthesis. The screening of the 588 quaternary catalysts is carried out in a specially designed 10-fold parallel gas flow micro-structured reactor as wall catalysts in sequential operation mode at a temperature of T = 573 K and a pressure of p = 15 bar. For the description of the activity, the reaction parameters CO2 conversion, CH4 yield, and CH4/CO2 selectivity are used. These are determined by analyses of the gas phase composition using µGC-FID. The catalysts with the highest activities are validated in a micro-structured reactor with similar characteristics as the screening reactor in the temperature range between T = 573–673 K and a pressure of p = 15 bar. Characterization by powder X-ray diffraction, Raman spectra, and scanning transmission electron microscopic images data on the phase and element distribution after calcination and reduction was conducted.

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Itkulova, Sholpan, Gaukhar Zakumbaeva, Aliya Mukazhanova, and Yerzan Nurmakanov. "Syngas production by biogas reforming over the Co-based multicomponent catalysts." Open Chemistry 12, no. 12 (December 1, 2014): 1255–61. http://dx.doi.org/10.2478/s11532-014-0571-x.

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AbstractThe new multicomponent Co-based catalysts with additives of group 8 metal and rare earth elements and supported on alumina have been tested in the dry and steam conversion of a model biogas. The processes were carried out in a flow quartz reactor under the following conditions: atmospheric pressure, a gas hourly space velocity of 1000 h−1 and temperatures of 300–800°C. The catalysts were characterised using electron microscopy, BET and X-ray analysis.The methane is almost completely converted in the dry reforming of biogas at T≤800°C. Synthesis gas with a ratio of H2/CO>1.0 is a main product of biogas reforming over the multicomponent catalysts studied. Adding steam in a feed composition increases both the methane conversion and the hydrogen yield at lower temperatures. Almost complete methane conversion occurs at T<750°C in the steam reforming of biogas. The catalysts are highly effective and exhibit stable activity throughout 100 h of continuous testing.

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Journal articles on the topic 'Gas conversion; Synthesis; Metal carbide'

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