Carbon Monoxide Oxidation on Nanostructured Pt Thin Films Synthesized by Pulsed Laser Deposition: Insights into the Morphology Effects

Fatma Saidani,Mohamed Mohamedi,Dominic Rochefort

doi:10.1155/2010/143684

Abstract

Nanostructured Pt thin film catalysts of various morphologies have been synthesized by pulsed laser deposition and studied towards enhancing their tolerance to CO poisoning, a reaction of critical issue to liquid fuel cells. It was discovered that Pt film deposited under 5 Torr of He background pressure showed the highest electroactive surface area and the lowest onset potential of CO oxidation demonstrating an enhancement of the CO poisoning resistance. The reason for such enhanced electrocatalytic activity is ascribed to the high roughness of Pt surface. This study further provides a methodology for the proper design of electrocatalysts that might be considered to be developed by the pulsed laser deposition technique.

Highlights

Carbon monoxide (CO) oxidation is one of the most investigated heterogeneous reactions, being scientifically and industrially essential, principally for removal of CO from exhaust streams and preferential oxidation in fuel-cell applications
SEM images of Figure 1 show the remarkable differences in the morphology between the pulsed laser deposition (PLD)-synthesized Pt under vacuum (Figure 1(a)) and those under increasing He background pressures (Figures 1(b)–1(f))
The crystallographic orientation was studied by recording the Selected Area Electron Diffraction (SAED) patterns (Figure 2(c)) demonstrates the polycrystalline nature of the Pt deposit

Summary

Introduction

Carbon monoxide (CO) oxidation is one of the most investigated heterogeneous reactions, being scientifically and industrially essential, principally for removal of CO from exhaust streams and preferential oxidation in fuel-cell applications. Within this quest, Direct Alcohol Fuel Cell (DAFC) is a promising technology for transportation and portable electronic devices, and both methanol and ethanol are strong contenders for such low-temperature fuel cells because they are hydrogen-rich liquids, they possess high energy density, and they can be produced in great quantities from biomass [1]. Because of their small size and large surface-to-volume ratio, nanoparticles (NPs) may lead to an increase in the catalytic efficiency, and in the mean time allow very low loading Pt catalyst to be employed

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Conclusion