BN crystal, basic structure of boron nitride nanotubes.

boron nitride (BN) crystal, assigned to an orthorhombic space group (No. 31, 2), is reported here. This new BN crystal exhibits a 'linear' morphology for high-resolution transmission electron microscopy (HRTEM) and a (non-hexagonal) 'diagonal' electron-diffraction pattern, which have been experimentally demonstrated in this article.

Dispersion of Cobalt Nanoparticles on Nanowires Grown on Silicon Carbide-Alumina Nanocomposites.

Silicon carbide-alumina nanocomposite supports including a nanowire architecture for a high dispersion of cobalt nanocatalysts were fabricated using a modified sol–gel process and paste extrusion process to form cylindrical shape beads, followed by thermal treatment. Well-developed aluminosilicate nanowires were formed on a nanoporous support, which are grown from a catalytic metal seed at the nanowire growth tips during heat treatment at 1,100 °C for 1 h under nitrogen gas flow. Cobalt oxide precursors were highly dispersed on the nanowires grown on the surface of the nanoporous bodies through a supercritical carbon dioxide fluid-assisted wet-impregnation process.

Effect of Tungsten Addition on Nickel-Based Catalyst for Combined Steam and CO2 Reforming of Methane.

In this study, we investigated the effect of tungsten addition on Ni-based catalyst in methane steam-CO₂ reforming. All the catalysts were prepared by the co-impregnation method with varied tungsten loading. The as-prepared catalysts were characterized by inductively coupled plasma atomic emission spectrometer, X-ray diffraction, temperature-programmed reduction and thermogravimetric analysis.

Nickel Supported on Mesoporous Alumina for Dry Reforming of Methane: Combustion Method.

Ni catalysts supported on ordered mesoporous alumina (OMA) were prepared by EISA method and calcined under air and Ar atmospheres. Both catalysts showed stable performance for the dry reforming of methane for 24 h, however the catalytic activity of Ar calcined catalyst was relatively lower than that in the air calcined one. It was found that the carbon (C β ) layer around nickel particles was observed for the Ar calcined catalyst after dry reforming of methane.

Raman Radial Mode Revealed from Curved Graphene.

One of the unsolved fundamental issues of graphene is establishing an appropriate way to discern layers of graphene structures. We report a simple methodology to analyze graphene structures using Raman signals in the range of ∼100 to ∼500 cm comprising clear 118 or 175 cm peaks. We demonstrate that the low-energy signals on Raman spectra of plasma-seeded grown graphene sheets originated from nanocurvature (c) of mono- (175 and 325-500 cm signals) (c ≈ 1 nm) and bilayer (118 cm peak) (c ≈ 2 nm) graphene with Raman simulations, based on Raman radial mode (RM) Eigen vectors.

The Nature of Metastable AA' Graphite: Low Dimensional Nano- and Single-Crystalline Forms.

Over the history of carbon, it is generally acknowledged that Bernal AB stacking of the sp carbon layers is the unique crystalline form of graphite. The universal graphite structure is synthesized at 2,600~3,000 °C and exhibits a micro-polycrystalline feature. In this paper, we provide evidence for a metastable form of graphite with an AA' structure.

The Effect of Fe in Perovskite Catalysts for Steam CO2 Reforming of Methane.

In this work, La0.95Sr0.05Ni(1-x)Fe(x)O3 catalysts were prepared by modified EDTA-cellulose method and the catalysts were characterized by various techniques such as N2 physisorption, TPR, XRD, SEM, TEM-EDS and TG analysis.

Studies on the Role of Nitrogen in the Feed for Fischer-Tropsch Synthesis Under Fixed-Bed Reactor System.

In this study, Co/Al203 catalyst for Fischer-Tropsch synthesis was prepared via slurry impregnation method and the catalyst was characterized by various techniques such as TPR, XRD, TGA and N2 physisorption. To dissolve the wax, after-reaction catalyst was dewaxed using n-Hexane at 60 *C. The experiments were performed in a bench-scale fixed-bed reactor, under the reaction condition of 230 degrees C, 20 bar and feed volume ratio of H2:CO:N2 = 2:1:0.

Glycerol Steam Reforming Over Ni-Fe-Ce/Al2O3 Catalyst: Effect of Cerium.

In this work, hydrogen production from glycerol by steam reforming was studied using Ni-metal oxide catalysts. Ni-based catalyst becomes deactivated during steam reforming reactions because of coke deposits and sintering. Therefore, the aim of this study was to reduce carbon deposits and sintering on the catalyst surface by adding a promoter.

Carbon Deposition Onto Ni-Based Catalysts for Combined Steam/CO2 Reforming of Methane.

The present study was performed to suppress carbon deposition by Ce and Fe onto Ni-based catalysts in combined steam/CO2 reforming of methane (CSCRM), which is a process for producing synthesis gas (H2:CO = 2:1) for gas-to-liquids (GTL). The catalytic reaction was evaluated at 900 degrees C and 20 bar with a reactant feed ratio CH4:CO2:H20:Ar = 1:0.8:1.

Kinetic Study on the Effect of Chromium Addition to Ni-Based Catalysts for the Steam-CO2 Reforming of Methane.

In the present work, the kinetic effects of Ni-based catalysts containing various amounts of Cr on the steam-CO2 reforming (SCR) of methane were studied. Kinetic expressions for the SCR of methane over the Ni-based catalysts have been proposed using the power-law rate expression, based on the kinetic data obtained. In addition, the Arrhenius equation was used for calculating the activation energy.

Hydrogenolysis of Glycerol to 1,2-Propanediol Over Clay Based Catalysts.

1,2-propanediol (1,2-PDO) is one of the promising product among the valuable products derived from glycerol and it can be obtained by the catalytic hydrogenolysis of glycerol. Copper-supported clay-based catalysts were prepared with different pore sizes using various ratios of kaolin, Mg, and Al by coprecipitation and applied in the selective hydrogenolysis of glycerol to 1,2-PDO. In recent research, variations of pore volume and pore size could affect the diffusion of reagents within the catalyst due to the collision between reagents or pore wall and reagents.

Effect of Bimetallic Ni-Cr Catalysts for Steam-CO2 Reforming of Methane at High Pressure.

The present work was to carry out the development of high performance Ni-based catalyst for Steam-CO2 reforming of methane (SCR) which is suitable for Fischer-Tropsch synthesis of GTL- FPSO (floating, production, storage and offloading) process. The bimetallic Ni-Cr catalysts were prepared by co-impregnation method. The Ni and Cr loading amount were fixed at 12 wt% and 3~7 wt%, respectively.

Kinetics for Steam and CO2 Reforming of Methane Over Ni/La/Al2O3 Catalyst.

Kinetic studies of mixed (steam and dry) reforming of methane on Ni/La/Al2O3 and Ni/La-Co (1, 3 wt%)/Al2O3 catalysts were performed in an atmospheric fixed-bed reactor. Kinetic parameters for the mixed reforming over these catalysts were obtained under reaction conditions free from heat and mass transfer limitations. Variables for the mixed reforming were the reaction temperature and partial pressure of reactants.

Formation and Characterization of Ni Nanofiber Catalysts on Nickel Metallic Foam by Electrospinning Process.

We report the fabrication of nickel nanofiber catalysts supported on nickel metallic foam using a modified electrospinning with a grounded rotor and sequential reduction process. The robust deposition of aligned Ni nanofibers with a uniform morphology on the highly porous surfaces of the metallic foam could be achieved by controlling electrospinning parameters such as applied voltage, tip-collector-distance (TCD), concentration of polymer, and humidity. The diameters of the obtained nanofibers decreased with increasing voltage and TCDs.

Ni/MgO-MgAl2O4 Catalysts with Bimodal Pore Structure for Steam-CO2-Reforming of Methane.

The bead type MgO-MgAl2O4 catalyst supports with bimodal pore structures were fabricated via an extrusion molding of gels derived from the precursor mixture of mesoporous MgO particles and aluminum magnesium hydroxide, followed by heat treatment. To investigate the effect of macro pore structures on the catalytic activity of the Ni/MgO-MgAl2O4 catalysts in the steam and carbon dioxide reforming of methane (SCR), two kinds of the catalysts with largely different macro pore volumes and sizes but nearly the same meso pore volume and size were compared. The bimodal catalyst with a large macro pore size and volume exhibited a highly enhanced CO2 conversion from 22.

Modified Nano-Perovskite Catalysts for the Steam and CO2 Reforming of Methane.

This paper describes the synthesis and characterization of La0.8Sr0.2NiO3 nano-perovskite type catalyst for steam-CO2 reforming (SCR) and CO2 reforming (DR) of methane.

Steam Reforming of Glycerol Over Nano Size Ni-Ce/LaAlO3 Catalysts.

In this work, hydrogen production from glycerol by Steam Reforming (SR) was studied by Ni-Ce catalysts supported on LaAlO3 perovskite in order to effect of the cerium loading amount and the reaction conditions. Nano size Ni-Ce/LaAlO3 catalysts were prepared by precipitation method. The structure of the catalysts was characterized by XRD analysis.

The Influence of Promoter on Ni(15)/La(5)/γ-Al2O3 Catalyst in CO2-Steam Reforming of Methane to Syngas at High Pressure.

Catalysts were investigated with respect to catalytic activity and coke formation in combined steam and carbon dioxide reforming of methane to develop a highly active and stable catalyst for gas to liquid processes. Ni/La-X/Al2O3 (X = Co, Ce, Mo) catalysts were prepared by an impregnation method. The combined steam and carbon dioxide reforming of methane reaction were studied as a function of high pressure (20 bar) in a fixed bed reactor system.

Methanol Synthesis Over Cu-ZnO-Al2O3 Catalyst at Low Pressure.

A series of Cu-ZnO-Al2O3 catalysts were prepared by coprecipitation method. The pH of solution was adjusted from 6 to 8 by using Na2CO3 solution. The prepared catalysts were evaluated for methanol synthesis from syngas (H2, CO and CO2) at lower temperature and pressures.

The Effect of Cobalt Loading on Fischer Tropsch Synthesis Over Silicon Carbide Supported Catalyst.

A series of Co (5-30 wt%) based SiC supported catalysts were prepared by impregnation method and investigated for FTS reaction. The FTS reaction was carried out in a fixed bed reactor system with the H2/CO molar ratio of 2, reaction temperature of 230 degrees C and reaction pressure of 20 bar for 120 h. All catalysts were characterized by N2 physisorption, XRD, TPR, SEM and TEM techniques.

Carbon Deposition from the CO2-Steam Reforming of Methane Over Modified Ni/γ-Al2O3 Catalysts.

The aim of this work is to study the catalytic activity and suppression of carbon deposition in the CO2-Steam reforming of methane (SCR) to develop a high performance catalyst for GTL-FPSO application which is required to high pressure (20 bar) for F-T synthesis. Ni/La-X(6)/Al2O3 (X = Ce, Mg, Zr) catalysts were prepared by the impregnation method. The catalytic reaction was studied in a fixed bed reactor system at high pressure.

Synthesis and characterization of SiC nanocomposite catalyst supports with self-formed nanowires.

Nickel-loaded SiC-alumina structural catalysts containing nanowires were facilely fabricated via modified sol-gel process mediated by supercritical carbon dioxide, followed by thermal-treatment. The nanowires were formed by metal-catalyzed growth on the outer and inner parts of SiC-alumina nanocomposite beads containing more than 3 wt.% of the metal seed at a moderate temperature of 1,100 degrees C under nitrogen gas flow.

Synthesis and characterization of magnesium oxide supported catalysts with a meso-macropore structure.

Nanostructured magnesium oxide catalyst support materials with controlled morphology and size were synthesized from a supercritical carbon dioxide/ethanol solution via chemical reaction of soluble precursors and subsequent thermal decomposition. Leaf-like magnesium hydroxide precursors with high specific surface area were formed by a low-temperature chemical reaction at below 140 degrees C, while magnesium carbonate cubes with a very low surface area less than 3.3 m2/g were formed by temperature-induced phase transition from a loose to a dense structure during carbonation reaction at above 150 degrees C.

Preparation and characterization of Cu-based catalysts for methanol synthesis in MeOH-FPSO process.

A series of Cu-ZnO based catalysts have been synthesized by the wet impregnation method at different pH, and after calcinations, have been evaluated for the synthesis of methanol in the temperature range 220 to 260 degrees C at 35 bar with space velocity of 3,000 h(-1) and feed molar ratios of H2/CO = 2. The catalysts have been characterized by XRD, SEM, elemental analysis, surface area and porosity measurements. It is found that the catalyst synthesized at pH 7 is most active with a CO conversion of 35.