Mathiyarasu, J. and Remona, A.M. and Mani, A. and Phani, K.L.N. and Yegnaraman, V. (2004) Exploration of electrodeposited platinum alloy catalysts for methanol electro-oxidation in 0.5 M H2SO4: Pt-Ni system. Journal of Solid State Electrochemistry, 132 (8). pp. 968-975. ISSN 1432-8488

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Abstract

In this work, we examine the electrocatalytic activity of electrodeposited Platinum (Pt)-Nickel (Ni) alloy layers on an inert substrate electrode for methanol oxidation reaction. Analyses using energy-dispersive fluorescent X-ray analysis and powder X-ray diffractometry confirm alloying of Pt with Ni in a range of compositions. Steady-state polarisation measurements in 0.5 M methanol+0.5 M H2SO4 solutions clearly show that the onset of electro-oxidation shifts to less anodic potential values (approximately 160 mV), while also exhibiting current enhancements up to 15 times the currents obtained for the pure Pt electrodeposit. A linear relationship between the cyclic voltammetric peak (oxidation) current and [MeOH] is observed at a scan rate of 50 mVs)1, thus indicating reduced influence of adsorbed CO (COads) surface poison. A critical composition, Pt (92%)/Ni (8%) [denoted Pt-Ni(3) alloy] is found to exhibit maximum electrocatalytic activity, beyond which the activity drops, whereas pure Ni does not catalyse the reaction. While the promotion of electrooxidation is understood to be largely due to the alloy catalyst, surface redox species of Ni oxide formed during the electro-oxidation process may also contribute to the oxygenation of COads, thereby enhancing the oxidation current. Plausible mechanisms of methanol oxidation on Pt/ transition metal alloy electrocatalysts are discussed in terms of electron transfer (in the alloy) and the role of Ni oxide species.

Item Type:	Article
Uncontrolled Keywords:	Platinum-nickel; Electrodeposition; Cyclic voltammetry; Methanol oxidation
Subjects:	Electrodics and Electrocatalysis
Divisions:	UNSPECIFIED
Depositing User:	ttbdu cecri
Date Deposited:	06 Apr 2012 05:26
Last Modified:	06 Apr 2012 05:26
URI:	http://cecri.csircentral.net/id/eprint/981

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