H. Narumi, THEORETICAL EXPLANATION OF THE HYDROGEN WAVE ON A PLATINUM SINGLE-CRYSTAL ELECTRODE, Bulletin of the Chemical Society of Japan, 70(8), 1997, pp. 1777-1785
Voltammograms observed on basal planes of a Pt single crystal electrod
e in 0.1 M HClO4 were analyzed theoretically. Adsorbed hydrogen atoms
were assumed to form 2-dimensional (111), (100), and (110) lattices. T
hese lattices were treated by applying the Huckel method to an element
ary domain consisting of 400x200 lattice points with periodic boundary
conditions. Results explained the essential aspects of the butterfly
at Pt(111) and the hydrogen waves at Pt(100) and Pt(110). The lateral
interactions of the adsorbed hydrogen atoms were attractive in all cas
es and their values were estimated. The value at Pt(110) reproduced th
e previous one derived from the adsorption isotherm analysis. The squa
re-shaped wave observed at Pt(111) in a potential range of 0.05-0.35 V
was explained by an entirely different model for a freely moving part
icle. The analysis suggested that the square wave is due to electrons
which move freely in the adsorption layer. The Huckel method was furth
er applied to S-dimensional lattices having 2 to 3 layers. Results sug
gested a striking effect of the absorbed hydrogen beneath the surface
on the hydrogen wave.