title: In situ site-selective transition metal K-edge XAS: a powerful probe of the transformation of mixed-valence compounds.
abstract: We present herein the first in situ site-selective XAS experiment performed on a proof-of-principle transformation of a mixed-valence compound: the calcination of the K0.1Co(II)4[Co(III)(CN)6]2.7·20H2O Prussian Blue analogue (containing Co(2+) and Co(3+) ions in two different Oh sites) into Co3O4 (containing Co(2+) ions in a Td site and Co(3+) in an Oh site). By recording the Co K-edge X-ray absorption spectra using a spectrometer aligned at the Co Kβ1,3 emission line, the evolution of each species was singly monitored from 20 °C up to the oxide formation. The experimental spectrum of the Co(2+)(Td) and Co(3+) (Oh) species in Co3O4 is reported for the first time. Our results demonstrate the possibilities offered by site-selective XAS for the investigation of chemical transformations and the study of materials under working conditions whenever the chemical element of interest is present in several states and/or sites.
authors.affiliation: ICMMO, Université Paris-Sud, UMR CNRS 8182, Equipe de Chimie Inorganique, Rue du doyen Georges Poitou, 91405 Orsay Cedex, France. amelie.bordage@u-psud.fr.
authors.forename: Amélie
authors.initials: A
authors.lastname: Bordage
authors.forename: Virgile
authors.initials: V
authors.lastname: Trannoy
authors.forename: Olivier
authors.initials: O
authors.lastname: Proux
authors.forename: Hugo
authors.initials: H
authors.lastname: Vitoux
authors.forename: Robinson
authors.initials: R
authors.lastname: Moulin
authors.forename: Anne
authors.initials: A
authors.lastname: Bleuzen