Electrochemical faceting of single crystal platinum electrodes

Changes in real surface area, crystallographic orientation and morphology of platinum electrodes caused by periodic potential treatments: phenomenological approach

“…The SEM images of the treated surface ( Fig . 9b-d) show the formation of a metal platinum layer with a symmetric distribution compatible with the (111)-type preferred orientation [14] (Fig . 9b,c) .…”

“…The polyfaceted se platinum spheres were prepared by melting the end of 0 .5 mm diameter platinum wires with a small oxygen-gas torch flame, followed by cooling in air . The symmetry and distribution of the principal crystallographic poles of the resulting surfaces were followed through optical microscopy and SEM images [14,15] . The potential of the working electrode was measured against a RHE in acid electrolyte .…”

“…6c) with the characteristic fourfold macroscopic symmetry around the flat [100] crystallographic poles ( Fig . 6b) as already described for single crystal platinum surfaces [14,15] . should be noticed that for f = 0 .25 kHz a net increase in R can be observed only after ca.…”

Electrochemical faceting of polycrystalline gold in 1 M H2SO4

“…Recently electrochemical faceting was investigated more extensively for different solid metal electrodes by employing either single-crystal or polycrystalline electrodes in order to learn about the kinetics and mechanism of the process and the conditions needed to achieve reproducible electrode surfaces both in terms of orientation and roughness [5-131. In this direction, several electrochemical procedures were developed recently for producing electrochemical faceting at metal electrode surfaces through the application of relatively fast periodic potential perturbations covering a certain preset range of potentials and frequencies [5][6][7]10,12,13]. One of these procedures [5,6,10] consists in the application of a square wave potential function at frequencies of the order of 1 kHz or more within the potential range of H-and 0-adatom electroadsorption and electrodesorption at the submonolayer or monolayer level. This procedure was applied to promote (lOO), (110) and (111) faceting of polycrystalline and single-crystal platinum specimens.…”

STM/SEM correlative study of facetted gold

“…The frequency of the a.c. signal used in the etching, about 0 . 8 kHz, produces a preferred orientation with various features (terraces, steps, pyramids) depending on facet orientation (Canullo et al, 1986). The sample, after this treatment, present two well-defined zones, as can be seen in the SEM image (Fig.…”