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Magnetic recykling of complex catalysts immobilized on thiol-functionalized polymer supports

Abstract

In this work, the application of the thiol-functionalized epoxy resin encapsulated on magnetic core as supports for palladium catalysts is reported. The study focuses on obtaining of heterogeneous catalysts which can be separated by magnetic field. Palladium complex catalyst [PdCl2(PhCN)2] has been heterogenized by anchoring to these supports via ligand exchange reaction. The characterization of polymeric supports and heterogenized palladium catalysts has involved research methods like time-of-flight secondary ion mass spectrometry (TOF-SIMS), scanning electron microscopy (SEM) and nitrogen BET surface area measurements. The activity and stability during long-term use of the investigated catalytic systems were tested in a Heck and hydrogenation reaction. The influence of the type of thiols used as epoxy hardeners and the morphology of the supports on the catalytic properties of epoxy-supported palladium catalysts was discussed.

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Spectroscopic studies of alumina supported nickel catalysts precursors: Part II - catalysts prepared from alkaline solutions

Spectroscopic studies of alumina supported nickel catalysts precursors: Part II - catalysts prepared from alkaline solutions

Nickel alumina supported catalysts were prepared from alkaline solutions of hexaamminenickel nitrate by CIM and DIM methods (classical and double impregnation, respectively). The catalysts exhibited different nickel species due to the existence of various metal-support interaction strengths. As a consequence, the reducibility and other surface properties changed as a function of the preparation method. The aim of this work was to study the interaction between the metal precursor and alumina surface by means of FT-IR (Fourier transform infrared) and FT-IR/PAS (FT-IR photoacoustic spectroscopy).

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Synthesis and characterization of Pt/CeOx systems for catalytic CO oxidation reaction

Synthesis and characterization of Pt/CeOx systems for catalytic CO oxidation reaction

Four different ceria supported catalyst were prepared by impregnation method with Pt(NO3)2 solution. The two supports are commercially available (MaTeck) and the other two were prepared by precipitation and microwave assisted hydrothermal method (MAH) respectively. The phase composition and average crystallite size of the catalysts were characterised with XRD technique. Finally the catalytic activity in CO oxidation reaction were determined in plug flow reactor in temperature range 300-900 K with 1 K resolution. The catalysts obtained in both precipitation and MAH methods exhibit catalytic activity at room temperature whereas catalysts obtained on MaTeck supports are not active at those conditions. In turn, catalysts based on MaTeck support are more active in temperature range 420-700 K. The different activities are attributed to difference in average crystallite sizes and in support morphology.

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Synthesis of multi-walled carbon nanotubes with controlled inner and outer diameters by ethylene decomposition over Ni/MgO and Co/MgO catalysts

Abstract

In this work, multi-walled carbon nanotubes (MWCNTs) with significantly different mean diameters were produced by catalytic CVD over Ni and Co-based supported catalysts. Our results indicate that Ni nanoparticles in the Ni/MgO catalyst are responsible for controlling the inner diameters of the carbon nanotubes. Contrary, Co nanoparticles in the Co/MgO catalyst control the outer diameters of MWCNTs. The “base-growth” mechanism and smaller diameters of the MWCNTs grown on the Ni/MgO catalyst are associated with a strong metal-support interaction (SMSI) resulting from NixMg1−xO mixed oxide formation. The concept of the weak metal-support interaction (WMSI) between Co nanoparticles and MgO for the Co/MgO catalyst confirms the “tip-growth” mechanism of the MWCNTs.

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Promoted cobalt oxide catalyst on the metallic structured reactor filling for VOC combustion as an alternative to noble metal catalysts

Promoted cobalt oxide catalyst on the metallic structured reactor filling for VOC combustion as an alternative to noble metal catalysts

VOC combustion is a demanding process for both the reactor and the catalyst design. As we have proved in recent papers the diffusional limitation of reaction rate that occurs during combustion may be overcome by designing the metallic microstructures used as reactor internals. Their application on an industrial scale depends on the development of an efficient method of catalyst layering on metallic supports and the optimisation of a fine catalyst structure which would not change the elaborated microstructure geometry. In this study we propose the Langmuir-Blodgett (LB) film method to deposit various metals (Al, Co) in the form of catalyst organic precursors. The film forming abilities of the precursors were checked by surface pressure measurements upon film compression, Brewster Angle Microscopy and by the monolayers stability measurements. The amount of the deposited materials was controlled by the LB parameters and verified by the TG measurements. The catalyst obtained in this way were characterized at various stages of the preparation by SEM/XFS, XPS, AFM and RM methods and tested in n-hexane combustion. Oxidation of the Al washcoat precursor led to the formation of γ-Al2O3 improving the properties of the Al2O3 layer (α phase) developed on the pre-calcined CrAl carrier. Oxidation of cobalt stearate deposited on the CrAl produced dispersed Co3O4 spinel. The cobalt catalysts were active in combustion showing resistance to sintering. Compared to standard Pt supported catalyst it demonstrated twice as low activation energy (50 kJ/mol).

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ToF-SIMS studies of the surface of Pd/ZrO2-TiO2 catalyst used in the hydrodechlorination process

References Grams J., Szynkowska M. I.: Applications of Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) to Investigations of Metal/Support Catalysts, in Norris C.P. (Ed.), Focus on Surface Science Research, Nova Science Publishers, p. 69 - 97, 2005 . Grams J., Góralski J., Kleczewska J., Szczepaniak B., Sobczak I., Kusior A.: Selected Examples of an Application of Time-of-Flight Secondary Ion Mass Spectrometry to Surface Investigations of Catalysts Utilized in the Environment Protection, Pol. J

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Scientific co-operation with professor Nazimek

). D. Nazimek, J. Ryczkowski, Influence of the crystallite size of platinum on the course of the hydrogenolysis and isomerization of n-butane over Pt/Al 2 O 3 catalysts, React. Kinet. Catal. Lett. , 40, 137 (1989). D. Nazimek, J. Ryczkowski, Influence of the crystallite size of platinum on the course of the hydrogenolysis of ethane and propane over Pt/Al 2 O 3 catalysts, React. Kinet. Catal. Lett. , 40, 145 (1989). J. Ryczkowski, D. Nazimek, Influence of organic reagents on nickel alumina supported catalysts. I

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Catalytic oxidation of organic pollutants

Catalytic oxidation of organic pollutants

The paper presents the results of the measurements of the catalytic activity of V2O5/TiO2 and MoO3/TiO2 catalysts (8,10,12 and 15 wt % of V2O5 or MoO3 on TiO2 - anatase, respectively), prepared in our laboratory, in the complete oxidation (combustion) process of chosen volatile organic pollutants of the air such as methanol and n-butyl acetate. The activity of these catalysts was compared with the activity of industrial catalysts: supported platinum - Pt-p (0.15 wt % of Pt on γ-Al2O3) and MCA (15 wt % of CuO and 6 wt % of ZnO on γ-Al2O3). The investigations were carried out in the kinetic region (powder of the catalysts with the diameter in the range of 1.02-1.2·10-4 m) and for the chosen catalysts also in the diffusion region (the grains of the catalysts having the diameter of 2.5·10-3 m). On the basis of the obtained results the analysis of the process was performed.

It has been stated that reaction rate is well-described by the first order equation in relation to the methanol or n-butyl acetate concentration. On the basis of the obtained results in the kinetic region for all the applied catalysts the parameters of Arrhenius equation were determinated.

The comparison of the results for the kinetic region with the results for the diffusion region for the chosen catalysts allowed the calculation of the effective coefficients of diffusion. The parameters of Arrhenius equations as well as the effective coefficients of diffusion show a good correlation with the values obtained for the catalytic combustion of other organic pollutants of the air.

The measurements were carried out using a flow tubular reactor. The flow rate of the reaction mixture was kept constant 20 dm3/h (5.56·10-6 m3/s) in each test, using the space velocity of 20 s-1. It has been stated that the use of the applied catalysts led to the almost total oxidative destruction of both pollutants. Only H2O and CO2 were found as the final products of the reaction. The complete oxidation of the methanol process runs at the lower temperature than that of the complete oxidation process of n-butyl acetate. The most active at the combustion of methanol was the Pt-p catalyst. It demonstrates a comparable activity to molybdenum - titanium catalysts and the slightly lower activity than vanadium - titanium catalysts in the combustion of the n- butyl acetate process. The MCA catalyst was less active than the others in the oxidation of both compounds. The structures of the catalysts were tested using the X -ray analysis (XRD), infrared spectroscopy and scanning microscopy (SEM).

The results of the investigations show that V2O5/TiO2 and MoO3/TiO2 catalysts, especially the most active of them the 8% V2O5/TiO2 catalyst can be used in industrial systems for the purification of the air and industrial waste gases with VOCs, replacing the more expensive noble metals supported catalysts.

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Application of catalysts in the treatment of selected waste chloroorganic compounds

of toxic organic compounds occurring in industrial wastes with application of catalysts, Pol. J. Chem. Technol. , 2002 , 4, 8. Kułażyński M., Van Ommen J. G., Trawczyński J., Walendziewski J.: Catalytic combustion of trichloroethylene over TiO 2 -SiO 2 supported catalysts, Appl. Catal. B: Environmental , 2002 , 36, 239. Żarczyński A., Gorzka Z., Paryjczak T., Kaźmierczak M., Szczepaniak B.: Dioxins in the process of 1,1,2,2-tetrachloroethane oxidation with the application of monolithic catalysts, Pol. J

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Montmorillonite as the catalyst in oxidation of limonene with hydrogen peroxide and in isomerization of limonene

.10.006. 12. Nagendrappa, G. (2011). Organic synthesis using clay and clay-supported catalysts. Appl. Clay Sci. 53, 106–138. DOI: 10.1016/j.clay.2010.09.016. 13. Stekrova, M., Kumara, N., Aho, A., Sinev, I., Grünert, W., Dahl, J., Roine, J., Arzumanov, S.S., Mäki-Arvela, P. & Yu. Murzin, D. (2014). Isomerization of α-pinene oxide using Fe-supported catalysts: Selective synthesis of campholenic alde-hyde. Appl. Catal. A: General. 470, 162–176. DOI: 10.1016/j.apcata.2013.10.044. 14. Comelli, N., Avila, M.C., Volzone, C. & Ponzi, M. (2013). Hydration of α

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