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

摘要

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 cycliv oltammetry and in-situ STM in 0.1 M H_2SO_4. 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 oxgyen during cooling induces surface defects and leads to rough surfaces. Cooling inpure N_2 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 advantaeuos 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.