Chemical imaging of single catalyst particles with scanning μ-XANES-CT and μ-XRF-CT. Issue 1 (14th November 2014)

• Record Type: Journal Article
• Authors: Price, S. W. T.; Ignatyev, K.; Geraki, K.; Basham, M.; Filik, J.; Vo, N. T.; Witte, P. T.; Beale, A. M.; Mosselmans, J. F. W.
• Is Part Of: Physical chemistry chemical physics. Volume 17:Issue 1(2015)
• Page Start: 521
• Page End: 529
• Publication Date: 2014-11-14
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c4cp04488f
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : Representative Pt L3 edge XANES spectrum and sample reconstructed fluorescence maps during a XANES tomography experiment. Abstract : The physicochemical state of a catalyst is a key factor in determining both activity and selectivity; however these materials are often not structurally or compositionally homogeneous. Here we report on the 3-dimensional imaging of an industrial catalyst, Mo-promoted colloidal Pt supported on carbon. The distribution of both the active Pt species and Mo promoter have been mapped over a single particle of catalyst using microfocus X-ray fluorescence computed tomography. X-ray absorption near edge spectroscopy (XANES) and extended X-ray absorption fine structure revealed a mixed local coordination environment, including the presence of both metallic Pt clusters and Pt chloride species, but also no direct interaction between the catalyst and Mo promoter. We also report on the benefits of scanning μ-XANES computed tomography for chemical imaging, allowing for 2- and 3-dimensional mapping of the local electronic and geometric environment, in this instance for both the Pt catalyst and Mo promoter throughout the catalyst particle.