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In situ intermediate-energy X-ray catalysis research at the advanced photon source beamline 9-BM

Paper ID Volume ID Publish Year Pages File Format Full-Text
54940 47032 2013 7 PDF Available
Title
In situ intermediate-energy X-ray catalysis research at the advanced photon source beamline 9-BM
Abstract

A specially-designed catalysis reaction cell was used for acquiring X-ray Absorption Near Edge Structure (XANES) with heating and gas treatment in an intermediate-X-ray energy regime (∼2.1–4 keV) at the Advanced Photon Source beamline 9-BM. In situ X-ray measurements in this energy range can be complicated due to absorption by cell components, the reaction gases themselves, air surrounding the reaction cell, and a host of other reasons. As a proof of concept, bimetallic palladium catalysts were examined from the Pd LII and LIII edges, at approximately 3.2 keV. The XANES edge position, the height of the “white line” peak, and the shape of the peak display significant changes with alloy formation and CO adsorption. This in turn shows that the Pd L-edge XANES are very sensitive to changes in the d-band density-of-states and can be used to derive rich information about how a supported Pd, or other 4d transition metal catalyst, behaves when under reaction conditions or upon alloy formation.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (188 K)Download as PowerPoint slideHighlights► A intermediate-energy XANES in situ reaction cell was designed. ► Pd L-edges were probed in a supported bimetallic PtPd catalyst. ► Pd L-edge XANES was compared to that of Pt under treatment with CO. ► In contrast to Pt, both the Pd LIII and LII edges participated in CO bonding. ► Pd LIII XANES is also sensitive to alloy formation in a suite of 4d-M catalysts.

Keywords
XAFS; XANES; Intermediate-energy; In situ; Catalysis; Pd L-edges XANES; Pt L-edge XANES; Alloy formation
First Page Preview
In situ intermediate-energy X-ray catalysis research at the advanced photon source beamline 9-BM
Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 205, 30 April 2013, Pages 141–147
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis