Aa. Elshafei, STUDY OF NICKEL UPD AT A POLYCRYSTALLINE PT ELECTRODE AND ITS INFLUENCE ON HCOOH OXIDATION IN ACIDIC AND NEARLY NEUTRAL MEDIA, Journal of electroanalytical chemistry [1992], 447(1-2), 1998, pp. 81-89
The nickel underpotential deposition (upd) process at a Pt electrode w
as studied using the cyclic voltammetric technique. In strong acidic m
edium, Ni upd takes place in the hydrogen adsorption-desorption region
. The maximum coverage was found to be approximate to 0.55 monolayer a
t 10(-3) M Ni2+ ions in phosphate buffer (pH approximate to 6.85). The
estimation of the electrosorption valence gave a value of ca. 2 with
a replacement of one adsorbed hydrogen atom by each deposited Ni atom.
The Ni upd coverage was found to depend on the surface structure of t
he Pt electrode. The oxidation of HCOOH was inhibited by Ni upd and th
e inhibition effect became more pronounced as the pH increased. (C) 19
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