X-ray absorption spectroscopy and heterogeneous catalysis

X-ray absorption spectroscopy and heterogeneous catalysis In order to afford a deeper understanding of heterogeneous catalysts activity, an accurate correlation of the catalytic performances with the depiction of the active sites is required. Located at the catalyst surface, the active sites exhibit very precise geometry that determines the catalytic properties (conversion, selectivity). One of the best-suited technique able to describe these structures is X-ray absorption spectroscopy (XAS, including XANES and EXAFS) that allows assessing the electronic properties (the oxidation state) and the geometry (qualification and quantification of neighbouring entities) of the absorbing atom. The recent development of in situ and operando time-resolved XAS setups permits now to access the aforementioned features in working conditions both during the activation of the catalyst and during the reaction itself. This article points out the potentialities of XAS through the presentation of typical studies representing various fields of catalysis and covering the successive life steps of a catalyst, i.e. from its synthesis to the genesis of the active phase by activation, till its evolution during reaction. Finally, recent developments are considered involving the study of model catalytic systems with new XAS applications and new spectral interpretation approaches by ab initio modelling.