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Reduction Study of Iron-Alumina Binary Oxide Fe2-xAlxO3

Jóźwiak W. K., Maniecki T. P., Mierczyński P., Bawolak K., Maniukiewicz W.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 12

2153-2162

EN

The comparative study of iron-aluminum binary oxides Fe2-xAlxO3 (where x = 2/3, 1, 4/3) reduction behavior was investigated and the obtained bi-oxides were characterzed by TPR, TG-DTA, BET and XRD methods. In hydrogen atmosphere three step reduction path way for iron-aluminum binary oxide was found. Such reduction behavior appeared reasonably analogical to that characteristic of hematite type iron(III) oxide reduction 3Fe2O3 rightwards arrow 2Fe3O4 rightwards arrow 6FeO rightwards arrow 6Fe. The reduction for unimolar bi-oxide Fe2-xAlxO3 (x = 1) can be expressed in following way: 4FeAlO3 rightwards arrow 2Fe2AlO4 rightwards arrow 2FeAl2O4 + 2Fe rightwards arrow 4Fe but the last step of reduction was not accomplished below 1000°C. In air FeAlO3 bi-oxide decomposes above 1300°C, whereas exothermal dissociation 2FeAlO3 rightwards arrow alfa-Al2O3 and alfa-Fe2O3 above 770°C was con firmed in argon atmosphere.

2

Methanol Synthesis from CO2 and H2 Mixture over 60 per cent Cu/support (FeAlO3, ZnAl2O4) Catalysts

Maniecki T. P., Mierczyński P., Bawolak-Olczak K., Jóźwiak W. K.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 9

1653-1662

EN

The aim of this work was to determine the correlation between catalytical activity of copper supported catalysts 60 per cent Cu/support (FeAlO3, ZnAl2O4) in methanol synthesis and their physicochemical properties. Surface area measurements (BET), X-ray diffraction (XRD) and temperature-programmed reduction (TPR-H2) techniques were used to study the physicochemical properties of Cu/support catalysts. The activity tests in methanol synthesis were carried out over copper catalysts in the temperature range 180–260 graduate C at elevated pressure (4 MPa) in a fixed bed reactor. Monometallic supported catalyst 60 per cent Cu/FeAlO3 was more active, but less selective in comparison with 60 per cent Cu/ZnAl2O4 catalyst in methanol synthesis. The XRD results confirmed the presence of binary oxide (ZnAl2O4 and FeAlO3), copper oxide, alfa-Fe2O3 and ZnO for appreciate copper supported catalysts. A reduction study of copper catalyst confirmed two step of copper oxide reduction (Cu2+ rightwards arrow Cu+rightwards arrow Cu0).

3

Characterization of Cu-(Ag, Au)/CrAl3O6 Methanol Synthesis Catalysts by TOF-SIMS and SEM-EDS Techniques

Maniecki T. P., Mierczyński P., Bawolak K., Leśniewska E., Rogowski J., Jóźwiak W. K.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 9

1643-1651

EN

Characterization of bimetallic Cu-Ag and Cu-Au catalytic systems supported on CrAl3O6 was carried out by TOF-SIMS, XRD and SEM-EDS techniques. The evidence of alloying of copper and second metal was observed during catalyst reduction as well as methanol syntheis reaction. The promoting effect of noble metal catalysts on copper catalyst was noticed. Modification by gold or silver improves activity up to ten times.

4

Methanol Synthesis from Mixture of CO, CO2 and H2 under Atmospheric Pressure over Au, Ag-Cu/FeAlO3 Supported Catalysts

Maniecki T. P., Mierczyński P., Maniukiewicz W., Bawolak K., Gebauer D., Jóźwiak W. K.

Polish Journal of Chemistry

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2008

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Vol. 82, nr 12

2379-2388

EN

The influence of copper and noble metal (Ag, Au) addition on the physicochemical properties of support FeAlO3 and supported metal catalysts was studied. The reaction of methanol formation in the temperature range 200-380 graduate C under atmospheric pressure over a series of Cu and M-Cu catalysts (where M = Ag, Au) has been investigated. The presence of spinel like type structures FeAlO3, Fe2AlO4 and FeAl2O4 was confirmed by XRD technique. The physicochemical properties of supports and supported copper and bimetallic Ag, Au-Cu/FeAlO3 catalysts were examined by BET, TPR, and XRD methods.

5

Gold as Promoter of Nickel Supported Catalysts for Semi Combustion of Methane

Maniecki T. P., Bawolak K., Mierczyński P., Jóźwiak W. K.

Polish Journal of Chemistry

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2008

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Vol. 82, nr 12

2389-2399

EN

The gold influence on catalytic activity, stability and carbon deposition of supported nickel based catalysts was studied. The monometallic 5%Ni/Al2O3 and bimetallic 5%Ni-x%Au/Al2O3 (x = 2, 1, 0.5, 0.25, 0.1) systems were prepared by wet impregnation. The catalytic tests in partial oxidation of methane at 25-900 graduate C and long term stability tests at 900 graduate C during 24 h were carried out. The CH4 dissociative decomposition and CO disproportionation processes were run at the same temperature range. Carbon deposition was studied by TG analysis and catalysts investigations by TPR and XRD measurements. The results indicated that gold addition improved both catalytic activity and resistance towards carbon deposition.

6

Characterization of Au-Cu, and Au-Ni Spinel Supported Catalysts for Partial Oxidation of Methane and Methanol Synthesis

Maniecki T. P., Mierczyński P., Bawolak K., Gebauer D., Maniukiewicz W., Jóźwiak W. K.

Polish Journal of Chemistry

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2008

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Vol. 82, nr 12

2367-2378

EN

The aim of this work was the determination of the effect of support and gold promotion on physicochemical properties, and catalytic activity in partial oxidation of methane and methanol synthesis. The kind and amount of coke deposition formed during partial methane oxidation (POM) and methanol synthesis (MS) were determined. The influence of gold addition on physicochemical properties of mono- and bimetallic (Cu, Fe, Ni) spinel (MgAl2O4, FeAlO3, ZnAl2O4, CrAl3O6) supported catalysts was determined. It was found that modification by gold-copper or nickel supported catalysts have no strong influence on their reducibility. Catalytic activity almost does not change before and after gold introduction for POM reaction and increases significantly for MS reaction. In both cases gold promotion decreases coke formation and makes easier its oxidation.