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Fe-Co/MgO is one of the most common catalyst mix applied to carbon nanotubes (CNTs) growth in chemical vapor deposition process. Therefore, here we present detailed study on the preparation and characterization of Fe-Co/MgO. The precursors of Fe and Co are iron (II) acetate and cobalt acetates, correspondingly. The molar ratio of the catalyst mix is Fe:Co:MgO=1:1:100. Initially, thermogravimetric analysis (TGA) of the mixture was performed. TGA analysis of it indicated the stepwise mass losses which pointed out the crucial thermal conditions for the changes in the elemental composition, morphology, crystallographic structure and vibrational properties. In current state of the art the lowest growth temperature for singlewalled carbon nanotubes is 550°C in CVD technique and here the characterization of the catalyst mix strongly suggest that this temperature can be decreased what would enhance the compatibility of CNT growth with current complementary metal-oxide-silicon (CMOS) technology for CNTs-based nanoelectronics. The morphology, crystallographic structure, elemental composition of the samples and its spectroscopic properties were performed via high resolution transmission electron microscopy (TEM), X-ray diffraction (XRD) and Infrared spectroscopy (IR), respectively.
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Pd-Ni/Al2O3 systems were investigated in the reaction of hydrogen oxidation in terms of their possible application as catalysts used in passive autocatalytic recombiners (PARs) used in nuclear power plants. Testing experiments were carried out in a flowing system at different temperatures and humidity of the reaction mixture. The bimetallic catalysts exhibited higher response to the increase of temperature and higher resistance to inhibit water than the monometallic palladium catalyst. They showed excellent stability during a few tens of hours, similarly, like their monometallic counterpart. Our bimetallic catalysts of hydrogen oxidation can be used as cheaper alternatives to catalysts based on the precious metals in the hydrogen oxidation without loss of their activity over time.
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A simple, low cast and efficient solvent-free procedure for the preparation of bis(in -dolyl)methanes via condensation of indoles with aldehydes as well as ketones in the presence of catalytic amount of magnesium sulfate (MgSO4) is described. The reactions proceed rapidly in high yields at 50°C.
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The largest amount of air pollutants is produced by the combustion of fossil fuels (coal, lignite, petroleum, natural gas, etc.). Such combustion releases huge amounts of greenhouse gases into the atmosphere (including carbon oxides (CO, CO2), sulphur oxides (SO2, SO3), nitrogen oxides (NO, NOx)) and dust, ashes and soot. Transportation is a significant share of the air pollution, mainly wheel-based transportation. The combustion process in diesel engine is very complex physico-chemically and varies in time. The process is accompanied by simultaneous exchange of heat and mass and chemical reactions. The development of internal combustion engines is made towards meeting of the increasingly stringent requirements for toxic exhaust emissions, reduction of fuel consumption, and preservation of Earth's natural resources. The problem to solve in modern diesel engines is the emission of toxic compounds. One way to reduce emissions is to use a catalytic converter positioned directly in the combustion chamber of an internal combustion engine. The aim of this analysis is assessment of toxic emissions of a diesel engine with an internal catalyst. Qualitative assessment of engine emissions was determined by comparing test results of an engine with ceramic-ally coated valves against one with just conventional valves (commercial valves - without a ceramic coating). The study utilized a fourcylinder 1.9 TDI VW engine. It was expected that the use of glow plugs with an active coating would reduce the release of toxic compounds.
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In the present work there have been shown the results of initial researches concerning heat release process in the spark ignition engine with inner catalyst. There has been presented the calculative model of heat release process and calculative methodology leading to obtaining temperature course, combustion function and its derivative because of measured course of combustion pressure. The pressure courses, which are necessary for calculations, were obtained on the measure seat with AD 1600 engine that is load with eddy- current brake. The engine was equipped with spark plug with miniature pressure sensor f-my Kistler, and the courses of pressure were recorded by the use of f-my Smetec apparatus. The courses of heat release process were analysed in rotations of n=1500 rotations/min and n=3000 rotations/minute and load of 50 Nm and 70 Nm. The analysis was made comparatively for the system with the catalyst and without catalyst. In the work there have been presented the results of experimental and model researches which aim was the analysis of the issue of influencing the catalytic active surfaces placed in the spark ignition engine combustion space. Those surfaces, catalysing the process of creating combustible mixture and its combustion, influence the combustion process course and, simultaneously, have impact on the engine work parameters and the heat release course.
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CuO nanoflakes were successfully synthesized by microwave irradiation, using copper(II) sulphate and sodium hydroxide (NaOH) as the starting materials and ethanol as the solvent. The CuO nanoflakes were characterized by using techniques such as X-ray powder diffraction, field emission scanning electron microscopy, and UV-visible absorption spectroscopy, Fourier transform infra-red spectroscopy. The synthesized CuO nanoflakes were found to have morphology like nanoflakes with narrow size distribution and high purity. Moreover, the synthesized CuO nanoflakes were used as an efficient catalyst for synthesis of a series of dihydropyridine derivatives. Optimization studies with different catalysts and solvents reveal that CuO nanoparticle in the water/ethanol mixture is efficient catalyst/solvent system for the synthesis of dihydropyridine derivative.
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This work presents the research results of the influence of modification deSONOx type catalyst of the sulfur dioxide emissions in the process of the hard coal combustion. The addition of zeolite catalysts modified by transition metal ions: V, Mg, activated by zinc sorbent with or without graphite addition caused the deeper burning of coal grains. The addition of the deSOx catalysts to the coal resulted in lowered sulphur dioxide emission. The addition of unmodified zeolite to coal during combustion reduced sulphur dioxide emission at about 5%. The modification of the support by both V and Mg reduced the amount of sulphur dioxide significantly. The obtained results of SO2 removal from exhaust gases were from 34.5% for Sip/Mg to 68.3% for Sip/V.
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Content available remote Złoto jako katalizator reakcji chemicznych
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Content available Studies of catalytic coal gasification with steam
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One of the promising processes, belonging to the so-called clean coal technologies, is catalytic coal gasification. The addition of a catalyst results in an increased process rate, in which synthesis gas is obtained. Therefore, the subject of this research was catalytic gasification of low-ranking coal which, due to a high reactivity, meets the requirements for fuels used in the gasification process. Potassium and calcium cations in an amount of 0.85, 1.7 and 3.4% by weight were used as catalytically active substances. Isothermal measurements were performed at 900°C under a pressure of 2 MPa using steam as a gasifying agent. On the basis of kinetic curves, the performance of main gasification products as well as carbon conversion degree were determined. The performed measurements allowed the determination of the type and amount of catalyst that ensure the most efficient gasification process of the coal ‘Piast’ in an atmosphere of steam.
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Content available remote Synteza ozonu w skojarzonym układzie wyładowanie ciche-UV-katalizator
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In this study, pyrolysis of shredded waste tire was carried out thermally and catalytically in a fixed bed reactor. Thermal pyrolysis was performed at temperatures of 330 °C, 430 °C, 530 °C, and 630 °C under Ar. flow rate of 0.5 L/min as a carrier gas and retention time of 15 min catalytic pyrolysis was carried out at temperature of 530 °C. The effects of temperature and two types of catalysts (CaCO3 and SiO2/Al2O3) were studied on the yield of pyrolysis products. Fourier transform infrared spectroscopy (FTIR) and Gas chromatography mass spectrometry (GC-MS) analysis for the oil products that were obtained by thermal and catalytic pyrolysis at 530 °C for chemical characterization. Oil, solid, and gas products yield by thermal pyrolysis at 530 °C were 50 wt. %, 35.6 wt. %, and 14.4 wt. % respectively, when the CaCO3 catalyst was used, the products distribution was 52 wt. %, 38.5 wt. %, and 9.5 wt. % respectively. While using SiO2 /Al2O3 the pyro oil, and char, and gas were decreased to 47 wt. %, 38 wt. %, and 15 wt. % respectively. The chemical composition of pyrolysis oil mainly included hydrocarbons compounds, predominantly Limonene which was represented by Cyclohexene, 1-methyl-4-(1-methylethenyl).
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To make clear the feasibility and influence factors of diesel fuel autothermal reforming to hydrogen, PdCeCr-FeCu/Al2O3 catalyst was prepared by equivalent-volume impregnation method. Experimental facility based on an adiabatic tubular reactor with preheating section was designed and set up, the behaviors of diesel reforming to hydrogen with straight-run diesel as a raw material according to the analysis of the components were studied. Diesel oil reforming over a catalyst for hydrogen production was analyzed using an adiabatic tubular reactor with a preheating section that was designed and built in-house. The operating conditions were optimized. Under the suitable operating conditions, viz., catalyst bed inlet temperature of 700°C, diesel liquid space velocity of 0.24 h–1, water-carbon ratio of 20, and oxygen-carbon ratio of 0.6, the hydrogen yield reached 28.3 (mol/mol).
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Content available remote Katalizatory procesu oksyetylenowania
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The aim of this research is to determine the minimum number of uncorrelated dimensions which can describe national competitiveness (NC). NC is thought of as the ability of a nation to provide a conducive environment for its firms to prosper. It is shown that the environment affects national productivity catalytically through the interactions with the production factors while itself remaining unchanged. Selected World Economic Forum’s indicators are used for determining the components of the environment. The Principal Component Analysis has revealed three orthogonal dimensions of NC. Countries are represented by the points in the three-dimensional space. The weighted Euclidean distance from the origin to the ith point is proposed as a novel measure of the ith country’s level of NC.
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In this study, carbon based bimetallic materials (Pd–Ni/C) were synthesized by polyol method in order to increase the hydrogen peroxide reduction catalytic activity of Pd using Ni metal. Hydrogen peroxide reduction and sensing properties of the prepared catalysts were measured by electrochemical methods. As a result, we have established that the addition of Ni at different ratios to Pd has a considerable electrocatalytic effect on H2O2 reduction. This work provides a simple route for preparation of Pd–Ni catalysts to create a very active and sensible electrochemical sensor for H2O2 sensing.
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Application of active coating inside of an self-ignition engine may have an important impact on several stages of combustion process: fuel cracking, fore-flame phase, combustion phase and secondary combustion phase [7]. Investigations of such construction are very rare in the literature - especially of hydrocarbons emission. Polycyclic aromatic hydrocarbons (PAHs) are known to have mutagenic and carcinogenic effect on humans [2, 6, 7]. One of the most important anthropogenic sources of these substances is motorization (especially diesel engines). The paper presents results of measurements of PAHs emissions from SB3.1 self-ignition engine with Pt active coating application inside. The catalyst was applied on engine valves surface. Zirconium ceramic was chosen as a coating for catalyst application (also because of its thermo-insulating properties). Because of unstable parameters of self-ignition engine work (pressure and temperature jumps), PAHs were extracted from two phases: gas phase and solid phase (particle matter - PM). A chromatographic method of PAHs identification and analysis, because of their low level of concentration in exhaust gases, needed to be supported by sample purification and enrichment stages [40]. It has been found that a significant decrease of total toxic polycyclic aromatic hydrocarbons concentration in engine exhaust gases for engine with Pt catalyst application. The catalyst application causes also changes in relative concentrations of polycyclic aromatic hydrocarbons.
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Industrial topics include SASOL alumina manufacturing processes, properties of boehmite aluminas derived from alkoxides aluminas and their catalyst uses, activated aluminas for fluid bed and pollution control catalysts, and silica-aluminas and hydrotalcites as acidic and basic support materials.
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