A new method for the preparation of Ru quasi single crystal surfaces

A new method for the preparation of Ru quasi single crystal electrode surfaces is described. Using the ‘forced deposition’ method followed by resistive heating in nitrogen, it is demonstrated that well-defined Ru films supported on Pt single crystal electrodes may be synthesised which, for the case of Pt{1 1 1} exhibit voltammetry similar to that reported for bulk single crystal Ru(0 0 0 1) electrodes. Moreover, systematic changes in the voltammetric response of the well-ordered supported Ru film upon varying the substrate surface crystallography from Pt{1 1 1} to Pt{1 0 0} (via a series of Pt n{1 1 1} × {1 0 0} and Pt n{1 0 0} × {1 1 1} stepped surfaces) demonstrate unequivocally the epitaxial nature of the films. For surfaces based on Pt{1 0 0} – (1 × 1) terraces, two sharp, intense peaks just positive of the potential of hydrogen evolution signify the presence of fcc Ru{1 0 0} terrace sites. This is significant because fcc {1 0 0} surface sites are not normally associated with hcp bulk phases. In addition, the voltammetric features usually ascribed to fcc {1 0 0} × {1 1 1} step sites and {1 1 1} terraces are clearly identified for the Ru films. The surfaces prepared by this method have been characterised by cyclic voltammetry (CV) in H2SO4. The most interesting facet of this new method is the ease of preparation of fcc Ru{h k l} surfaces relative to analogues derived from variously prepared single crystals of Ru.