Extraordinary Stability of IrO(110) Ultrathin Films Supported on TiO(110) under Cathodic Polarization.

Down to a cathodic potentials of -1.20 V versus the reversible hydrogen electrode, the structure of IrO(110) electrodes supported by TiO(110) is found to be stable by in situ synchrotron-based X-ray diffraction. Such high cathodic potentials should lead to reduction to metallic Ir (Pourbaix diagram).

studies of the cathodic stability of single-crystalline IrO(110) ultrathin films supported on RuO(110)/Ru(0001) in an acidic environment.

We investigate with in situ surface X-ray diffraction (SXRD) and X-ray reflectivity (XRR) experiments the cathodic stability of an ultrathin single-crystalline IrO2(110) film with a regular array of mesoscopic rooflike structures that is supported on a RuO2(110)/Ru(0001) template. It turns out that the planarity of the single-crystalline IrO2(110) film is lost in that IrO2(110) oxide domains delaminate at a cathodic potential of -0.18 V.

Growth of Ultrathin Single-Crystalline IrO(110) Films on a TiO(110) Single Crystal.

The growth of a flat, covering, and single-crystalline IrO(110) film with controlled film thickness on a single-crystalline TiO(110) substrate is reported. The preparation starts with a deposition of metallic Ir at room temperature followed by a post-oxidation step performed in an oxygen atmosphere of 10 mbar at 700 K. On this surface, additional Ir can be deposited at 700 K in an oxygen atmosphere of 10 mbar to produce a IrO(110) layer with variable thicknesses.