title: Solving the structure of reaction intermediates by time-resolved synchrotron x-ray absorption spectroscopy.
abstract: We present a robust data analysis method of time-resolved x-ray absorption spectroscopy experiments suitable for chemical speciation and structure determination of reaction intermediates. Chemical speciation is done by principal component analysis (PCA) of the time-resolved x-ray absorption near-edge structure data. Structural analysis of intermediate phases is done by theoretical modeling of their extended x-ray absorption fine-structure data isolated by PCA. The method is demonstrated using reduction and reoxidation of Cu-doped ceria catalysts where we detected reaction intermediates and measured fine details of the reaction kinetics. This approach can be directly adapted to many time-resolved x-ray spectroscopy experiments where new rapid throughput data collection and analysis methods are needed.
authors.affiliation: Physics Department, Yeshiva University, New York, New York 10016, USA.
authors.forename: Qi
authors.initials: Q
authors.lastname: Wang
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Hanson
authors.forename: Anatoly I
authors.initials: AI
authors.lastname: Frenkel
mesh_terms: D000042:Absorption; D002563:Cerium / Q000737:chemistry; D003300:Copper / Q000737:chemistry; D008956:Models, Chemical; D010084:Oxidation-Reduction; D025341:Principal Component Analysis; D013057:Spectrum Analysis; D017356:Synchrotrons; D013997:Time Factors; D014965:X-Rays
chemical_list: D002563:Cerium; C030583:ceric oxide; D003300:Copper