Metallic multilayered films electrodeposited over titanium as catalysts for methanol electro-oxidation

Electrochimica Acta Volume: 105 Pages: 578-583 Published: 2013

AFM images. (a) Fresh titanium used as substrate; (b) Ti/Pt; (c) Ti/Pt/Ir; (d) Ti/Pt/Ir/Pt.

Writers: Alana A. Zulke; Roberto Matos; Ernesto C. Pereira

Keywords: Metallic multilayer; Electrocatalysis; Titanium modified electrode; Methanol oxidation reaction

Abstract: Multilayered Pt/Ir/Pt films were electrodeposited over titanium substrates, controlling the film thickness by the deposition charge. Two probe molecules were used to perform the evaluation of catalytic activity, CH3OH and CO. Using a 22 factorial design with a central point, optimized intrinsic catalytic activity was obtained over the Ti/Pt25mC/Ir6mC/Pt electrode. An enhancement of the current density of up to 2.76 times was observed for the methanol oxidation reaction (MOR) compared with the reference sample (Ti/Pt electrodes), even though both samples had the same electroactive area. In addition to the methanol oxidation voltammetry, CO stripping voltammetry suggests that MM-like systems are less susceptible to the catalyst-poisoning phenomenon compared to the Ti/Pt ones. Impedance spectroscopy was mainly used to monitor the charge transference resistance (Rct), whose results showed a clear Rct reduction for the MOR process over MMs compared with Ti/Pt electrodes, corroborating the previous observations regarding the general catalytic improvement.

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DOI: 10.1016/j.electacta.2013.05.027

Robson Lima
Sobre Robson Lima 87 Artigos
Atua no Centro de Desenvolvimento de Materiais Funcionais.