Estudos da deposição em subtensão de cádmio sobre ouro policristalino na presença de diferentes ânions co-adsorvidos

Abstract

Cadmium UPD on Au was studied by voltammetric and microgravimetric measurements. In the oxide formation/reduction potential region, a mass increasing/decreasing of 32 ng cm-2 was associated to incorporation/elimination of one oxygen per active site. The modifications promoted in the voltammetric and mass profiles by 10-5 M Cd(ClO4)2 are restricted to potentials more negative than 0.4 V. After a 120 s potential delay at 0.05 V, the positive sweep reveals an anodic peak with charge of 40 μC cm-2 and mass decrease of 22 ng cm-2, associated to Cdads dissolution. Sulphate or chloride was added to the solution without significant influence, due to the low coverage with Cd or anions.