Session: Advances in Spectroscopy:

The overproduction of greenhouse gases highlights the need for renewable energy sources. One viable candidate for this is the direct methanol fuel cell (DMFC). Multi-walled carbon nanotubes (MWCNTs) have proved to be effective support material for expensive metal catalysts such as Pt to electrocatalytically act in DMFCs. Carbon monoxide (CO) is formed at the interface and disables the catalyst surface reducing DMFC efficiency. To understand the role that alloying the nanostructures supported by MWCNTs affects the CO poisoning on the surface of the electrocatalysts, metal nanostructures PtZn-MWCNTs and Pt-MWCNTs are studied. According to our electrochemical analysis results, the current density for methanol oxidation on the bimetallic structure is at least 5 times larger than that of the single Pt metal catalyst in 2M methanol and 0.1M H₂SO₄ solution. This indicates a better electrocatalytic behavior of the bimetallic alloy structures compared to single Pt nanoparticles on MWCNTs. The in situ spectro-electrochemical studies enable us to probe the molecules at the interface and investigate the intermediates formed. We report infrared measurements of CO binding to the electrode surface under electrochemically controlled conditions. Specifically, we show the potential dependent behavior of methanol oxidation reaction intermediates on Pt-MWCNT and PtZn-MCWNT electrode surfaces. Results from this study contribute to the greater understanding of DMFC and the applications in renewable energy.

Mr. Ramin Ordikhani Seyedlar

PhD Candidate, The University of Iowa

Appearances