Oxidation of ferrocene derivatives at a poly[Ni(saltMe)] modified electrode

• Tipo: Artigo em Revista Científica Internacional
• Data: 2002

Autores

Vilas Boas, M (Autor) Outra; Pereira, EM (Autor) Outra; Freire, C (Autor) FCUP; Hillman, AR (Autor) Outra

Revista

A Revista está pendente de validação pelos Serviços Administrativos.

Título: JOURNAL OF ELECTROANALYTICAL CHEMISTRY

Vol. 538

Páginas: 47-58

ISSN: 0022-0728

Indexação

ISI Web of Knowledge - 23 Citações

Scopus - 22 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Química

Outras Informações

ID Authenticus: P-000-M2A

DOI: 10.1016/s0022-0728(02)01097-5

Abstract (EN): The characterisation of film permeability and mediation properties of poly[Ni(saltMe)] modified electrodes were evaluated by studying the oxidation of ferrocene and 1,1'-dimethylferrocene at these electrodes by rotating-disk voltammetry. The effects of varying the substrate and its solution concentration, film thickness, rotation speed and electrode potential on the limiting current density were analysed using the model of Albery. Both substrate oxidations show two mechanisms, according to the applied potential. The first, direct reaction on the underlying electrode is controlled by substrate transport through the film (Et-S case). The second, polymer-mediated reaction occurred at higher potentials, and was the only substrate oxidation process observed for thick films. Mechanistic analysis for polymer-mediated oxidation revealed some dependence of the reaction zone on the substrate and its concentration. For the highest ferrocene concentrations, oxidation occurs in a thin reaction layer away from both interfaces (LRZt(e)t(S) case). However, for the highest concentrations of 1,1'-dimethylferrocene, the mediated reaction is controlled by substrate transport through the film and occurs close to the underlying electrode interface (LEtS case). As both substrate concentrations decrease, the heterogenous rate constants for the modified electrode, k'(ME), become essentially independent of film thickness and are consistent with rate limiting electron transfer at or near the film \ solution interface (Sk' or LSk cases).

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 12