Kinetical study about the cobalt electrodeposition onto polycrystalline platinum

Abstract

Recebido em 2/10/12; aceito em 25/2/13; publicado na web em 24/5/13An electrochemical study of Co electrodeposition onto polycrystalline Pt from an aqueous solution containing 10 −2 M CoCl 2 + 1 M NH 4 CI (pH = 9.3) was conducted at overpotential conditions. The current density transients showed two maxima that corresponded to two nucleation and growth processes. The entire transient behavior was adequately predicted considering the contribution to the total current of four different processes: a Langmuir-type adsorption process, a diffusion-controlled twodimensional instantaneous nucleation, and two three-dimensional nucleation and growth processes.

Theoretical quantum study about the adsorption of BH4 - onto X(100) where (X = Cu, Ag and Au)

“…The greatest extension value of HOMO, calculated at B3LYP/LANL2DZ level, was observed on hollow positions; see Figure 3a, 3b and 3c for copper, silver and gold respectively. These results are consistent with the previously reported in literature [15][16][17]. Note the BH 4…”

“…A second one consists in increasing the cluster size until the electronic properties do not change in the center of the cluster. For Cu(100) the varia- tion in the charge values in the center of the cluster is less to 3% when the cluster size is bigger than four unit cells [16,17]. Similar results have been obtained for gold and silver.…”

“…The orientation (100) was selected because it is the main crystallographic face exhibited by fcc metals [57]. In present work we employed the electronic unit cell (EUC) [15][16][17]. An EUC is defined as the minimal number of atoms maintaining a structural (crystallographic) pattern that is capable to model a particular electronic property of certain solids or surfaces [15][16][17].…”

“…However, it is important to consider that an adsorption process may change the electronic properties of the surface including its oxidation potential. It has been reported that Cu, Ag and Au show a periodic pinpoint distribution of the electrophilic actives sites [15][16][17]. Thus, it is possible to suggest the BH 4…”

A Semiempirical PM6 Study of Some Aminopyrimidine Derivatives and their Interaction with an Iron Surface

“…We used crystallographic parameters for their construction (26). The electronic unit cell (EUC), defined as the minimal number of atoms maintaining a structural (crystallographic) pattern that is capable to model a particular electronic property of certain solids or surfaces was obtained following the methodology reported previously by our group (27,28). In order to investigate the effect of the corrosion inhibitor, we analyzed from semiempirical PM6 study the redistribution of active sites on iron surface occasioned by 2-aminopirimidyne, 2,4-diaminopirimidyne and 2,4,6-triaminopyrimidine inhibitors, see Figure 1.…”