Kinetic analysis of carbon monoxide and methanol oxidation on high performance carbon-supported Pt–Ru electrocatalyst for direct methanol fuel cells | Health & Environmental Research Online (HERO)

Health & Environmental Research Online (HERO)

Print Feedback Export to File

This record has one attached file:

Citation
Tags

HERO ID

741452

Reference Type

Journal Article

Title

Kinetic analysis of carbon monoxide and methanol oxidation on high performance carbon-supported Pt–Ru electrocatalyst for direct methanol fuel cells

Author(s)

Velázquez-Palenzuela, A; Centellas, F; Garrido, JA; Arias, C; Rodríguez, RM; Brillas, E; Cabot, PL

Year

2011

Is Peer Reviewed?

Yes

Journal

Journal of Power Sources
ISSN: 0378-7753

Publisher

Elesevier Science B.V., P.O. Box 211 Amsterdam 1000 AE Netherlands

Volume

196

Issue

Page Numbers

3503-3512

DOI

10.1016/j.jpowsour.2010.12.044

Web of Science Id

WOS:000289325000017

URL

http://linkinghub.elsevier.com/retrieve/pii/S0378775310022500
Exit

Abstract

The kinetic parameters of carbon monoxide and methanol oxidation reactions on a high performance carbon-supported Pt-Ru electrocatalyst (HP 20% 1:1 Pt-Ru alloy on Vulcan XC-72 carbon black) have been studied using cyclic voltammetry and rotating disk electrode (RDE) techniques in 0.50 M H sub(2)SO sub(4) and H sub(2)SO sub(4) (0.06-0.92 M) + CH sub(3)OH (0.10-1.00 M) solutions at 25.0-45.0 degree C. CO oxidation showed an irreversible behaviour with an adsorption control giving an exchange current density of 2.3 x 10 super(-6) A cm super(-2) and a Tafel slope of 113 mV dec super(-1) ( alpha = 0.52) at 25.0 degree C. Methanol oxidation behaved as an irreversible mixed-controlled reaction, probably with generation of a soluble intermediate (such as HCHO or HCOOH), showing an exchange current density of 7.4 x 10 super(-6) A cm super(-2) and a Tafel slope of 199 mV dec super(-1) ( alpha = 0.30) at 25.0 degree C. Reaction orders of 0.5 for methanol and -0.5 for proton were found, which are compatible with the consideration of the reaction between Pt-CO and Ru-OH species as the rate-determining step, being the initial methanol adsorption adjustable to a Temkin isotherm. The activation energy calculated through Arrhenius plots was 58 kJ mol super(-1), practically independent of the applied potential. Methanol oxidation on carbon-supported Pt-Ru electrocatalyst was improved by multiple potential cycles, indicating the generation of hydrous ruthenium oxide, RuO sub(x)H sub(y), which enhances the process.

Keywords

Pt-Ru nanoparticles; Electrocatalysis; Methanol oxidation reaction; Temkin isotherm; Kinetic parameters