Papers by Keyword: Catalyst Support

Abstract: Platinum (Pt), a noble metal, is known for its ability to regenerate and be recycled even without any reactivation procedure, and still demonstrated good stability. The cost of the noble metal can be reduced by incorporating the metal into the pores of catalyst support rather than using it individually. Hence, in this research study, 4 wt.% Pt supported on silica-alumina (SiO₂-Al₂O₃) and gamma-alumina (γ-Al₂O₃) was synthesized using wet impregnation method, then followed by catalyst calcination at 500 °C. The catalyst was then characterized using Thermogravimetric Analysis (TGA), Fourier-Transform Infrared Spectroscopy (FTIR), Brunauer–Emmett–Teller (BET), and particle size analyzer where catalyst with high surface area and pore volume demonstrated an excellent performance for the catalytic reaction of cellulose. Experimental results showed that catalyst Pt/SiO₂-Al₂O₃ with the highest surface area and pore volume (466.4 m²/g and 0.1157 cm³/g, respectively) exhibited the highest catalytic performance with the conversion of cellulose up to 65.8% and 30.9% levulinic acid (LA) yield produced at the reaction temperature of 200 °C in a semi-batch reactor for 8 hrs.

Abstract: Coconut tree fiber (CTF), representing a potentials feedstock from agricultural processing, was developed to porous carbon by microwave-assisted activation. CTF was transformed into CTF char before further activation. The CTF porous carbons (CTFCs) were obtained by the microwave-assisted activation using KOH as an activating agent at 700 W microwave radiation power. To investigate the effects of KOH on specific characteristics of CTFCs, the different ratios of KOH:CTFs char (i.e. 1:1, 1:2, 1:4, 1:8 w/w) were studied. CTFCs were extensively characterized on physicochemical properties including proximate & ultimate analysis, porous characteristics, and surface morphology. The porous carbon exhibits a combination of type I/type IV sorption isotherm representing the micro/mesopores in its pore structure. The optimal condition obtained the highest S_BET of 913.56 m²/g with total pore volume of 0.42 cm³/g. CTFC were potentially applied for metal catalyst support in various chemical reaction due to its high surface area and porosity to enhance the catalyst dispersion.

Abstract: The high interest in the synthesis of mesoporous catalyst demands that novel materials are developed with simple methods capable of improving process yields. In this work, a novel heterogeneous mesoporous catalyst support has been synthesized using mesoporous SBA-15 loaded with mixed bimetal oxides of CeO₂ and MgO. Formation of the SBA-15 was actuated in air at room temperature (25°C) and in oven conditions at 100°C after which cerium nitrate and magnesium nitrate precursors were then impregnated into the SBA-15 framework and calcined at 550°C for each of the air and oven crystallization processes. XRD peak patterns confirmed SBA-15 formation and dispersion of nanocrystallites of CeO₂ and MgO within the porous framework of SBA-15. Both the air and oven dried processes produced mesoporous MgO-CeO₂/SBA-15 catalysts with isotherms that exhibit typical H1 type hysteresis confirming that they possess open-ended cylindrical mesopores. The structural data extracted gave average pore size, pore volume and surface area values in the ranges of 3-5.2 nm, 0.600-2.500 cc/g and 400-500 m²/g respectively which is ideal for several industrial applications.

Abstract: PtRu or Pt catalysts were supported on four types of carbon nanomaterials with different shapes, sizes, and graphitic and electrical properties, and their resulting catalytic activities were evaluated by electrochemical methods. The carbon nanomaterials used included two types of particles: Arc Black (AcB) and Vulcan XC-72R (Vulcan), and two types of nanofibers: carbon nanocoils (CNC) and VGCF-X. Pt and Ru were loaded onto the nanomaterials by a reduction method using sodium borohydride. Transmission electron microscopy and X-ray diffraction (XRD) revealed the PtRu catalyst particles to be 4–6 nm in diameters. The shifts in the Pt (111) XRD peaks of the catalysts on CNC and VGCF-X were larger than those on AcB and Vulcan, indicating a higher degree of alloying between Pt and Ru. The diameters of the CNC-supported Pt and PtRu catalyst particles had the narrowest distributions and were constant within the range of catalyst loadings investigated. Electrochemical studies of the catalysts during methanol oxidation were carried out using cyclic voltammetry. The catalyst particles supported on CNC and VGCF-X exhibited higher catalytic activity than those on AcB and Vulcan. The effect of the surface area of the carbon nanomaterials on the catalytic activity is discussed.

Abstract: This paper aims at studying the porous cordierite ceramics prepared by using the non-stochiometric cordierite composition formulation (2.8MgO.1.5Al₂O₃.5SiO₂) by PU sponge impregnated method. The ceramic suspension were prepared with non-stoichiometric formulation of cordierite and sintered at 1250 °C, 1275 °C, 1285 °C, 1300 °C and 1325 °C. The phase transformation of non-stochiometric formulation cordierite was investigated by XRD. This paper also aims to compare the effect of linear shrinkage, porosity and density of 20 wt.% PEG treated PU sponge with untreated PU sponge respectively corresponding to different pore content (100 ppi, 80 ppi, 60 ppi, and 40 ppi). The pore structure was analyzed by SEM.

Abstract: Aluminium is found to play a key role in the process of forming a mechanically stable and highly porous and granular structure of 4H silicon carbide. The material is prepared by a high temperature reaction of the elemental constituents. The reactions are carried out under different background atmospheres, including nitrogen. Ternary carbides containing Al, Si and N, are formed in the process, and are believed to be responsible for the final outcome of the process, at the highest reaction temperatures, in the form of pure, well-connected grains of 4H-SiC forming a strong and rigid structure with high porosity. The Al containing compounds function as structural promoters for the 4H polytype recrystallization. This is expected - and partly shown - to take place through substitution with 4H-SiC and evaporation of all other constituents during the high temperature sintering step. When extruded into honeycomb structures prior to the sintering process this pure mesoporous SiC final product turns out to be ideal for a combined diesel particulate filter with support for catalysts in the pores.

Abstract: In low-temperature SCR, corn straws pyrolysis carbon (CS) was prepared as a catalyst support and activated carbon (AC) was a comparison. Manganese (7 wt.%) was loaded respectively on this two supports (Mn/AC and Mn/CS). In 50°C~300°C SCR experiment, the highest NO conversion by using CS is 36.6 Vol.% at 300°C, while AC 37.9 Vol.% at 200°C. After loaded the manganese element, NO conversion increases with the temperature. At 300°C, Mn/AC has the highest NO conversion (81.9 Vol.%), while Mn/AC is 65.3 Vol.%. The sulfur resistance performance test shows that NO conversion decreases with the increasing of SO₂ concentration. In the 400ppm SO₂ fuel gas at 300°C, using Mn/CS, NO conversion reduces 16.7 Vol.%, however, using Mn/AC, it reduces 22.6 Vol.%. It is promising to apply biomass pyrolysis carbon modified catalyst.

Abstract: Amorphous NiB supported on expanded vermiculite (EV) catalyst was prepared as an example to show the superior characteristics of EV as a novel carbon support material. EV and the prepared catalysts were characterized by ICP, SEM, TEM and SAED. The catalytic activity of prepared catalysts was tested by the hydrogenation of sulfolene to sulfalone, with the introduction of ultrasonication the NiB/EV-U catalyst performed very high catalytic activity.

Abstract: FeCrAl alloy powder is used to mix with an additive to prepare a powder mixed paste. FeCrAl alloy honeycombs are fabricated by extruding the powder mixed paste, then dried and sintered. While sintering at 1200°C, with sintering time increase, the volume of sintered honeycombs increase and density decrease. The structure parameters and properties of sintered honeycombs were obtained by measuring and calculating. Results show that wall thickness 0.18~0.23mm, cell number (1/in²) 316~339, clear cross section (%) 69~74, specific surface Sv (sq m/cu dm)2.35~2.52; specific heat capacity C_p(J/g.K) 0.60~0.70, heat conductivity κ (W/m.K) 6.52~6.78. SEM/XRD analysis shows that a large number of oxides formed on the surface of sintered honeycombs during sintering, such as Fe₂Cr₂0₄, Fe₂Si0₄, Al₂O₃.These oxides connect together to form film on surface of sintered honeycombs. By impregnating and baking test, the surface of sintered honeycomb can firmly adhere γ-Al₂O₃ catalytic washcoat. The oxide film formed on the surface sintered honeycombs is benefit for adhering and supporting the catalytic active components.

Abstract: NO_x is one of the most serious atmosphere pollutants, and how to control and remove NO_x is the hot research in the environmental field all over the world. SCR is considered as one of the most effective denitration methods at present. In SCR technology, catalyst is the core of the SCR system, and the performance of SCR catalyst mainly depends on the active component and catalyst support. Catalyst support can not only affect the choice of the active material and the catalyst promoter, but also affect the flue gas denitration efficiency. This paper mainly introduces four kinds of SCR catalyst supports: TiO₂, Al₂O₃, activated carbon and activated carbon fiber and ZSM-5 zeolite. The performance of the four types of catalyst supports are compared, and SCR activity test of Mn-Ce supported and V₂O₅ supported on different catalyst supports are conducted respectively. Finally, for Mn-Ce supported and V₂O₅ supported catalysts, this paper puts forward that TiO₂ is the most widely used and effective catalyst support.