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High throughput cell for X-ray absorption spectroscopy applied to study the effect of Au on Rh-catalyzed partial oxidation of methane

Paper ID Volume ID Publish Year Pages File Format Full-Text
43076 45954 2009 10 PDF Available
Title
High throughput cell for X-ray absorption spectroscopy applied to study the effect of Au on Rh-catalyzed partial oxidation of methane
Abstract

A parallel reactor cell for catalytic in situ X-ray absorption spectroscopy (XAS) measurements was developed. The cell facilitates the simultaneous catalytic and structural investigation of six catalysts under different feed gas conditions. A two-dimensional X-ray sensor was used for spectra collection. Gas compositions were measured by on-line mass spectrometry. The potential and limitations of the high throughput XAS cell are discussed. The heterogeneously catalyzed partial oxidation of methane (CPO) was chosen as a test reaction. Alumina-supported Rh and Au/Rh catalysts with different metal loadings (0.5–2.5 wt%) were applied and prepared via different preparation routes using flame spray pyrolysis (fsp) and colloid adsorption (col). For comparison the same catalysts were also investigated in a fixed-bed capillary reactor heated by a gas blower (also for XAS measurements) and in an eight-fold parallel gas phase reactor using similar reaction conditions (6% CH4–3% O2–He, 250–500 °C). Similar catalytic results were obtained in all three reactor types, confirming the suitability of the parallel reactor XAS cell for catalytic measurements. The catalysts showed different activity, selectivity and reducibility depending on metal loading, preparation route and Au/Rh ratio. The analysis of the catalytic data, STEM images and the in situ XANES experiments of the various catalysts indicated the following characteristics for the CPO reaction: sufficient heat production by combustion of methane, total conversion of oxygen, and reduction of a certain fraction of the catalyst. The overall catalytic behavior was in line with a two-zone model of the catalyst bed where catalytic combustion dominates in the front zone and reforming reactions become favored in the second part of the catalyst bed.

Graphical abstractThe effect of gold addition, metal loading and preparation route of alumina-supported rhodium catalysts on their catalytic behavior in the partial oxidation of methane is studied in a parallel in situ X-ray absorption spectroscopy (XAS) cell designed for simultaneous catalytic and structural investigation of six catalysts under different feed gas conditions. Potential and limitations of the high throughput XAS cell are discussed. Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
X-ray absorption spectroscopy; High throughput technology; In situ spectroscopy; Partial oxidation of methane; Gold; Rhodium; Alumina; Flame spray pyrolysis
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High throughput cell for X-ray absorption spectroscopy applied to study the effect of Au on Rh-catalyzed partial oxidation of methane
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volume 353, Issue 1, 31 January 2009, Pages 36–45
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us