Electrochemical behaviour of nano-faceted Ir(210)

摘要

Nano-faceted Ir(210) surfaces have been obtained by inductive heating and cooling in an oxygen-containing gas atmosphere. The behaviour of the nanostructured Ir(210) electrode in contact with 0.1 M H2SO4 has been studied by cyclic voltammetry and in-situ scanning tunnelling microscopy (STM). The nano-facets are found to be stable under electrochemical conditions, which is in agreement with theoretical predictions [P. Kaghazchi, W. Chen, H. Wang, I. Ermanoski, T.E. Madey, T. Jacob, ACS Nano 2 (2008) 1280]. A characteristic needle peak at -0.18 V in cyclic voltammograms for Ir(210) electrodes in sulphuric acid solution indicates the presence and quality of the faceted nanostructure. In-situ STM images show a homogenous distribution of small three-sided pyramids with an average size of ca. 30 nm. The nano-pyramids consist of facets with (311), (3 11) and (110) orientation. Adsorbed sulphate was observed by in-situ STM on the (110) facets. (C) 2008 Elsevier B.V. All rights reserved.