One Step Metal Particle Deposition and Solubilization of Single Wall Carbon Nanotubes for fuel cell applications

摘要

Research on direct methanol fuel cells (DMFC) has increased in recent years both from a fundamental and an application point of view.1'2 Most of the studies have been focussed on the development of Pt nanoparticles within the size regime of 3-5 nm.3 But there are very critical issues that need to be adressed as far as Pt nanoparticles are concered with regard to the poisoning effect. The intermediates like CO and HCOO, that are formed on the surface of the catalyst act as a poison and hinder the catalytic activity of the Pt surface.4 An alternative approach is to use nanoparticles of Au. The synthesis of monodisperse, stable gold nanoparticle of the order of 3-8 nm has been well studied in the literarture.5'6 The gist of the procedure involves the transfer of the AuCU" from aqueous to organic solution by using a phase transfer catalyst followed by the reduction in presence of a capping agent. In our present study, we have used tetraoctyl ammonium bromide (TOAB) as the capping agent. Maye's group have foccused their attention on using core shell assembled gold or other metal nanoparticles for reactions that are important for fuel cell applications (methanol, CO, oxidation reactions) and they indicate promising activity.7'8 Another area of increasing attention is the use of fullerenes and carbon nanotubes in fuel cells with special emphasis on methanol oxidation and oxygen reduction reactions.9'10'"'12 In this study, we focus on Au nanoparticles and Au-CNT nanoparticle composites for fuel cell reactions, We can cast these Au-CNT nanoparticle composites on an electrode surface in a single step using electrophoretic deposition. We have probed the electrochemical activity of SWCNT/Au electrodes for methanol oxidation and oxygen reduction reactions (ORR).