Abstract
The electrodeposition of Cu from diluted CuSO 4 in 0.5 M H 2SO 4 on columnar structured Pt electrodes was studied through voltammetry. For a constant set of experimental conditions, as the Pt electrode roughness is increased, bulk Cu electrodeposition tends to disappear, the amount of electro-adsorbed H atoms increases, and the coverage of Pt by 2-D Cu domains decreases. This means that under non-equilibrium conditions for diluted Cu 2+-ion-containing solutions and highly rough Pt substrates, 3-D Cu nuclei, and 2-D Cu and free Pt domains are simultaneously present at the initial stages of the process. In these cases, bulk Cu can be detected when the degree of Pt surface coverage by Cu atoms exceeds 0.5.
Highlights
There are a number of systems for which a complete 2-D monolayer of Me on a foreign substrate can be formed at potentials more positive than the reversible potential (E,)of the corresponding Me/Me+ redox couple[ 141
The early stages of Cu electrodeposition on a foreign metal substrate are interesting for understanding the mechanism of electrocrystallization of metals, including the transition from 2-D submonolayers to bulk Me deposits
The voltammograms recorded for different electrodispersed Pt electrodes (EDPtE) in 0.5 M H2S0, (Fig. 1) at u = 0.1 V s-’ exhibit the cathodic and the anodic 0-electrosorption current peaks located at 0.75 V and 0.7-1.4V, respectively
Summary
There are a number of systems for which a complete 2-D monolayer of Me on a foreign substrate can be formed at potentials more positive than the reversible potential (E,)of the corresponding Me/Me+ redox couple[ 141. Data on Cu[9] and Ag electodeposition[lO] on polycrystalline Pt at potentials (Ed)more negative than E, showed that the nucleation and 3-D metal overlayer growth involves a 2-D to 3-D rearrangement at growing sites Under those conditions the electrodeposited Me monolayer becomes unstable, and during a certain initial period of the electrodeposition process, free substrate and 2-D Me domains can coexist with 3-D Me nuclei. The influence of surface roughness on both underpotential (upd) and overpotential (opd) electrodeposition of Ag has been studied on columnar structured Pt electrodes[ll] The structure of these electrodes has been solved through the application of STM at the nanometre level[ 12,131 and their use is attractive for detecting surface rearrangements and other dynamic aspects of the Me surface at the early stages of electrocrystallization. The Cu/Cu*+ electrode reactions in the upd and opd ranges on EDPtEs were studied through voltammetry from 0.05 to 1.45 V in the 0.02-0.1 V S-I potential sweep (u) range
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call