In-situ STM characterisation of the surface morphology of platinum single crystal electrodes as a function of their preparation

A systematic study of the surface morphology of Pt(111) and Pt(100) electrodes as prepared by flame-annealing and cooling in different atmospheres (air, N-2, H-2 + N-2 and CO + N-2) is presented. The electrodes were characterised by cyclic voltammetry and in-situ STM in 0.1 M H2SO4. Preliminary voltammetric results for Pt(110) are also shown. In this case, Cu upd served as a structure sensitive probe. It was observed that the presence of oxygen during cooling induces surface defects and leads to rough surfaces. Cooling in pure Nz preserves the reconstructed Pt(100) and Pt(110) surfaces, while cooling in H-2 + N-2 or CO + N-2 lifts the reconstruction. The use of CO as the cooling gas turned out to be advantageous for the preparation of clean and well-ordered (1 x 1)-surfaces. The stability of reconstructed Pt surfaces in an electrochemical environment is discussed. For H-2 + N-2-cooled Pt electrodes, a clear influence of the H-2-concentration on the surface morphology was observed. (C) 2000 Elsevier Science S.A. All rights reserved.