Dj. Caruana et Jv. Bannister, SURFACE-PROPERTIES OF FRACTURED AND POLISHED PLATINUM MICROELECTRODES, Journal of electroanalytical chemistry [1992], 424(1-2), 1997, pp. 197-205
An investigation of the surface properties related to the method of mi
croelectrode fabrication is presented and discussed. The voltammetric
response in acidic media (sulphuric and formic acids) of fractured 25
mu m diameter wire which had been sealed in soft glass was used to inv
estigate the surface microstructure. SEM studies showed that the cryst
allite size of the fractured wire, which had previously been sealed in
glass, was large, and that a single crystallite may be exposed to the
solution surface. The effect of sealing the wire in glass on the bulk
properties of the wire is related to the voltammetric response in aci
d media. Thus, the surface of a polished platinum microelectrode seale
d in glass cannot be considered as truly polycrystalline. The response
s of fractured platinum wire sealed in soft glass in sulphuric acid an
d formic acid are predominantly Pt(111), when compared by non-linear r
egression and congruent analysis with the three low index faces of pla
tinum in the same acidic medium under the same conditions. This is exp
lained by the process of slip deformation, which involves the slipping
of Pt(111) planes (close packed planes or planes of highest atomic de
nsity) forming steps with the exposed surface predominantly Pt(111).