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Journal of Spectroscopy
Volume 2014, Article ID 480102, 7 pages
http://dx.doi.org/10.1155/2014/480102
Research Article

In Situ Dispersive EXAFS in Electrocatalysis: The Investigation of the Local Structure of IrOx in Chronoamperometric Conditions as a Case Study

1Dipartimento di Chimica, Università di Pavia, Via Taramelli 16, 27100 Pavia, Italy
2Dipartimento di Chimica, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy

Received 22 October 2014; Revised 16 December 2014; Accepted 18 December 2014; Published 31 December 2014

Academic Editor: Davidson Sajan

Copyright © 2014 Elisabetta Achilli et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

An in situ study with dispersive EXAFS (Extended X-Ray Absorption Spectroscopy) at the Ir- edge is performed to characterize Electrodeposited Iridium Oxide Films (EIROF) under chronoamperometric conditions. The technique monitors the local chemical environment and electronic structure of iridium during the oxidation of Ir(III) to Ir(IV) with a time resolution of milliseconds. The study is performed in both acidic and basic media. The Fourier transforms of the time-resolved EXAFS signals clearly show that the short-range structure of Ir is similar to that of rutile-type IrO2 and is maintained during the reaction, thus accounting for the flexibility of the structure of the electrode material in accommodating different oxidation states. From a more general point of view, the work demonstrates the capabilities of in situ experiments based on state-of-the-art dispersive EXAFS in clarifying the mechanistic aspects of electrochemical processes.