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Local Structure and Speciation of Platinum in Fresh and Road-Aged North American Sourced Vehicle Emissions Catalysts: An X-ray Absorption Spectroscopic Study

DOI: 10.1021/es404974e DOI Help

Authors: Peter W. Ash (Johnson Matthey) , David A. Boyd (Johnson Matthey) , Timothy I. Hyde (Johnson Matthey) , Jonathan L. Keating (Johnson Matthey) , Gabriele Randlshofer (International Platinum Metals Association) , Klaus Rothenbacher (European Precious Metals Federation) , Gopinathan Sankar (University College London) , James J. Schauer (University of Wisconsin-Madison) , Martin M. Shafer (University of Wisconsin-Madison) , Brandy M. Toner (University of Minnesota)
Co-authored by industrial partner: Yes

Type: Journal Paper
Journal: Environmental Science & Technology , VOL 48 (7)

State: Published (Approved)
Published: March 2014
Diamond Proposal Number(s): 5737

Abstract: Given emerging concerns about the bioavailability and toxicity of anthropogenic platinum compounds emitted into the environment from sources including vehicle emission catalysts (VEC), the platinum species present in selected North American sourced fresh and road-aged VEC were determined by Pt and Cl X-ray absorption spectroscopy. Detailed analysis of the Extended X-ray Absorption Fine Structure at the Pt L3 and L2 edges of the solid phase catalysts revealed mainly oxidic species in the fresh catalysts and metallic components dominant in the road-aged catalysts. In addition, some bimetallic components (Pt–Ni, Pt–Pd, Pt–Rh) were observed in the road-aged catalysts from supporting Ni-, Pd-, and Rh-K edge XAS studies. These detailed analyses allow for the significant conclusion that this study did not find any evidence for the presence of chloroplatinate species in the investigated solid phase of a Three Way Catalyst or Diesel Oxidation Catalysts.

Journal Keywords: Pt Speciation; EXAFS; Xanes; Vehicle Emissions Catalysts

Subject Areas: Chemistry, Environment, Energy


Instruments: B18-Core EXAFS

Other Facilities: Advanced Photon Source Synchrotron Radiation Centre, University of Madison Wisconsin