Temperature‐Programmed Reduction and Oxidation1A list of symbols used in the text is provided at the end of the chapter.

Knözinger, Helmut

doi:10.1002/9783527610044.hetcat0056

Cited by 6 publications

References 93 publications

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Catalyst Characterization—Heterogeneous

Stavitski

Beale

Weckhuysen

2010

Encyclopedia of Catalysis

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The study of catalysts under in‐situ conditions enables the catalyst scientist to identify and understand the important steps, e.g., the formation of important reaction intermediates and active sites, and stages in a catalyst?s lifetime, such as activation/deactivation. The development of characterization methods as well as the design and construction of appropriate in‐situ cells and reactor probes are inevitable in order to obtain such insight. Both spectroscopic and scattering techniques have been used in attempt to understand quantitative structure/composition‐activity/selectivity relationships in catalysis. Armed with such detailed knowledge about the catalyst, it is then possible for scientists to design, in a more rational way, new and efficient catalysts for sustainable production of bulk and fine chemicals as well as for the removal of harmful compounds in industrial catalytic processes. This chapter provides an overview of the in‐situ characterization techniques available for investigation of catalytic materials. The possibilities and limitations of the methods are discussed and illustrated with numerous case studies.

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Catalyst Characterization—Heterogeneous

Stavitski

Beale

Weckhuysen

2010

Encyclopedia of Catalysis

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Structure–Activity Relationships of Nickel–Hexaaluminates in Reforming Reactions Part I: Controlling Nickel Nanoparticle Growth and Phase Formation

Roussière

Schelkle

Titlbach³

et al. 2014

ChemCatChem

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Water‐in‐oil‐in‐water (W/O/W) and water‐in‐oil (W/O) emulsions of paraffin oil were prepared with sorbitan monooleate (Span 80)/polyoxyethylene sorbitan monooleate (Tween 80) or polyethylene glycol monostearate (SG‐6), respectively. The physical characteristics and the absorption of toluene gas in these emulsions were investigated to evaluate the influence of the emulsifier dosage and the oil/water ratio. Both investigated W/O/W emulsions provided high stabilities and low viscosities. The absorption of toluene gas was excellent, with little foam occurring during the absorption. Although the W/O emulsions with 2–5 % SG‐6 were of high stability, their high viscosities strongly limited their application as volatile organic compound absorbents. Stable emulsions consisted of small and uniform droplets and some emulsions underwent mild demulsification after the absorption.

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Cu‐Based Catalyst Resulting from a Cu,Zn,Al Hydrotalcite‐Like Compound: A Microstructural, Thermoanalytical, and In Situ XAS Study

Kühl

Tarasov

Zander

et al. 2014

Chemistry A European J

105

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A Cu-based methanol synthesis catalyst was obtained from a phase pure Cu,Zn,Al hydrotalcite-like precursor, which was prepared by co-precipitation. This sample was intrinsically more active than a conventionally prepared Cu/ZnO/Al2O3 catalyst. Upon thermal decomposition in air, the [(Cu0.5Zn0.17Al0.33)(OH)2(CO3)0.17]⋅mH2O precursor is transferred into a carbonate-modified, amorphous mixed oxide. The calcined catalyst can be described as well-dispersed "CuO" within ZnAl2 O4 still containing stabilizing carbonate with a strong interaction of Cu(2+) ions with the Zn-Al matrix. The reduction of this material was carefully analyzed by complementary temperature-programmed reduction (TPR) and near-edge X-ray absorption fine structure (NEXAFS) measurements. The results fully describe the reduction mechanism with a kinetic model that can be used to predict the oxidation state of Cu at given reduction conditions. The reaction proceeds in two steps through a kinetically stabilized Cu(I) intermediate. With reduction, a nanostructured catalyst evolves with metallic Cu particles dispersed in a ZnAl2 O4 spinel-like matrix. Due to the strong interaction of Cu and the oxide matrix, the small Cu particles (7 nm) of this catalyst are partially embedded leading to lower absolute activity in comparison with a catalyst comprised of less-embedded particles. Interestingly, the exposed Cu surface area exhibits a superior intrinsic activity, which is related to a positive effect of the interface contact of Cu and its surroundings.

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Temperature‐Programmed Reduction and Oxidation1A list of symbols used in the text is provided at the end of the chapter.

Abstract: The sections in this article are Introduction The TPR Experiment Kinetics and Mechanism of Reduction Mathematical Treatment of TPR Profiles and Influence of Experimental Parameters Examples Conclusion

Cited by 6 publications

References 93 publications

Catalyst Characterization—Heterogeneous

Catalyst Characterization—Heterogeneous

Structure–Activity Relationships of Nickel–Hexaaluminates in Reforming Reactions Part I: Controlling Nickel Nanoparticle Growth and Phase Formation

Cu‐Based Catalyst Resulting from a Cu,Zn,Al Hydrotalcite‐Like Compound: A Microstructural, Thermoanalytical, and In Situ XAS Study

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