Tungsten trioxide (WO3) nanorods have been prepared by a simple pyrolysis of surfactant encapsulated tungsten oxide clusters. These nanorods are characterized by XRD, Raman, electron microscopic techniques and cyclic voltammetry. Platinum nanoparticles have been supported on these WO3 nanorods. The electrocatalytic activity and stability of platinum loaded WO3 nanorods towards methanol oxidation have been studied and compared with that of platinum supported on bulk WO3 and commercial 20% Pt-Ru/C (J.M.) using electrochemical measurements. The results demonstrated that alteration of the morphology of the WO3 from bulk to 1D nanorods have resulted in comparable methanol oxidation activity as that of the commercial 20% Pt-Ru/C catalyst. © 2007 Elsevier B.V. All rights reserved.

Janarthanan Rajeswari

Balasubramanian Viswanathan

Thirukkallam Kanthadai Varadarajan

Cyclic voltammetry

Methanol

oxidation

Platinum

Tungsten compounds

X ray diffraction analysis

Electrochemical techniques

Methanol Oxidation

TUNGSTEN TRIOXIDES

nanorods

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Materials Chemistry and Physics

Methanol offers certain specific advantages over hydrogen; it is cheap, plentiful, and renewable from wood alcohol, and since it is a liquid, it is easily stored, transported, and distributed. A lower ionomer content limits the ionic conduction in the catalyst layer, while a higher ionomer content reduces the mass transport. Although the ionomer content controls the DMFC performance, the amount of ionomer used depends on the preparation method of the MEA. Therefore, the catalyst surface in the DMFC will be poisoned by many surface intermediates. Consequently, a suitable electrocatalyst must be developed that can resist poisoning by the surface intermediates created by partial oxidation. High efficiencies may be achieved because of the unique properties of nanomaterials, particularly vectorial transfer of charge in dimensionally modulated supports;90 additional benefits include the possibility of high surface areas, sufficient chemical resistivity, and superior mechanical strength.

Chemical Reviews

Anode catalysts for direct methanol fuel cells in acidic media: Do we have any alternative for Pt or Pt-Ru?

In this paper, carbon supported noble metal nanoparticles synthesized by using Keggin type polyoxometalate (POM), silicotungstic acid (STA), were effectively utilized as electrodes in an effort to improve the efficiency of electrochemical energy conversion processes related to direct methanol fuel cells. The excellent electron transfer and strong adsorption abilities of STA have been well exploited for the reduction of metal ions as well as the modification of carbon support to form Pt and Pt-Ru metal nanoparticles supported on carbon nanostructure composites (Pt/STA-C and Pt-Ru/STA-C) under microwave irradiation. Transmission electron microscopy results indicated that well-dispersed metal nanoparticles were formed on the carbon support. The electrocatalytic properties of Pt/STA-C and Pt-Ru/STA-C were analyzed by cyclic voltammetry and chronoamperometry through the methanol oxidation reaction for fuel cell applications. As compared with the commercial Pt-Ru/C (Johnson Matthey) and Pt/C and Pt-Ru/C electrocatalysts prepared by using the common hydrogen reduction method, the STA containing Pt/STA-C and Pt-Ru/STA-C synthesized by the method developed in this work exhibited lower onset potential, high activity with enhanced stability, and better tolerance toward poisoning by CO for the methanol oxidation reaction. ©2009 American Chemical Society.

Journal of Physical Chemistry C

Silicotungstic acid based carbon supported noble metal electrodes for energy conversion application

Platinum supported on high surface area tungsten trioxide (WO3) has received intensive attention in recent years, mainly because of its improved tolerance towards carbon monoxide (CO) poisoning during methanol oxidation and its enhanced electrocatalytic activity. However, the chemical instability of WO3 in acid medium is a major issue that hinders its application in fuel cell electrodes. In the present work, the stability of WO3 is shown to be improved by suitable Ti4 substition in the WO3 framework. However, the improvement in the stability of WO3 in acid medium was found to be significant only at lower amounts of Ti4 in the framework. On the other hand, the electrocatalytic activity of Pt loaded W1-xTixO3/C (x = 0.0, 0.05, 0.09 and 0.17) for methanol oxidation, evaluated by cyclic voltammetry, in acid medium follows the order: Pt-W0.83Ti017O3/C &gt; Pt-WO 3/C &gt; Pt-W0.91Ti0.09O3/C ∼ Pt-W0.95Ti0.05O3/C. The trend in the activity observed correlates well with that of the increase in the ohmic resistance of the electrode determined by electrochemical impedance spectroscopy. © 2004 Elsevier B.V. All rights reserved.

Journal of Power Sources

Synthesis, characterization and electrochemical studies of Ti-incorporated tungsten trioxides as platinum support for methanol oxidation

The template carbonization of polyphenyl acetylene yielded well aligned, cylindrical, mono disperse carbon nanotubes (CNT), which are effectively utilized to load Pt, Pt-Ru, and Pt-WO3 nano particles. The nanoparticles are effectively dispersed inside the tube with the particle sizes of around 1.2, 1.6, and 10 nm for Pt, Pt-Ru, and Pt-WO3, respectively. The electrochemical surface area of the CNT-based electrode was higher compared to the Vulcun XC 72R carbon, graphite, and glassy carbon (GC) electrodes. The X-ray photoelectron spectroscopic measurements revealed that the Pt and Ru are in metallic state and W is in +VI oxidation state. The higher activity of GC/CNT-Pt-WO3-Nafion for methanol oxidation compared to GC/CNT/Pt-Ru-Nafion and GC/CNT/Pt-Nafion suggests the better utilization of the catalytic particles. The stability of the electrode for methanol oxidation polarized at +0.6 V follows the order of GC/CNT/Pt-Ru-Nafion &gt; GC/CNT/Pt-WO3 &gt; GC/CNT/Pt-Nafion, and for the electrodes polarized at +0.4 V, the order is GC/CNT/Pt-WO3-Nafion &gt; GC/CNT/Pt-Ru-Nafion &gt; GC/CNT/Pt-Nafion. The differences in the stability possibly suggest the better tolerance of the adsorbed species of methanol oxidation for the GC/CNT/Pt-WO3-Nafion electrode (when it is polarized at +0.4 V).

Journal of Physical Chemistry B

Carbon nanotubes generated from template carbonization of polyphenyl acetylene as the support for electrooxidation of methanol

Electrochemistry Communications

Electrooxidation of methanol on carbon nanotubes supported Pt–Fe alloy electrode

An electrocatalyst for methanol oxidation based on tungsten trioxide microspheres and platinum

Carbon

Carbon nanofibers supported Pt–Ru electrocatalysts for direct methanol fuel cells

Tungsten trioxide nanorods as supports for platinum in methanol oxidation

Journal	Materials Chemistry and Physics
ISSN	02540584
Open Access	No