We would like to invite you to the talk
DIMENSION AND CHEMICAL STATE CHARACTERISATION USING NEW
VECTOR METHOD OF COPPER OXIDE NANOPARTICLES SUPPORTED
ON GRAPHITE BY X-RAY PHOTOELECTRON SPECTROSCOPY
Dr. Vincent Fernandez
Institute des Matériaux Jean Rouxel IMN, Nantes, Francie
on Thursday 3. 12. 2015, 11 am
(building 6, lecture hall F1 on ground floor, campus of Faculty of Science MU,
Kotlářská 2, Brno)
This talk will discuss an accurate determination of quantitative chemical
environment that is the main analysis field of XPS. In some rare trivial cases
reasonable input models will not significantly influence the fit result. But in
most cases, the accurate analysis of the chemical environment is completely
depends on several complex parameters such as the number of peaks,
component constraints and peak shape. The Informed Sample Model technique
(ISM), that we developed, allows forming a set of data to extract the peak
shape and the necessary number of components. ISM was applied to a real
sample consisting of graphite-supported ultra-small copper nanoparticles
catalysts used for the Meerwein arylation of pyrroles and 1,3-dipolar
cycloadditions. It is well known that the XPS analysis of copper nanoparticles is
a difficult case due to satellite peaks. One method to fit the data is to use
reference samples with the assumption that the peak shape is independent of
the particles size. We studied with the ISM technique the Cu 3p doublet to
measure the relative proportions of copper species Cu2O, CuO, Cu(OH)2 using
background subtracted components derived from Cu 3p. Both Cu 2p and Cu 3p
data are derived simultaneously by vector transformations of raw spectra. The
component model was capable of reproducing all Cu 3p spectra from a total of
twenty seven different samples without relaxation of any fitting constrains in
terms of position and shape