TUNING THE ACTIVITY OF PLATINUM ELECTROCATALYSTS VIA SIZE, SHAPE AND CAPPING POLYMER

Ceren Susut* and YuYe Tong (PhD Mentor)

Department of Chemistry, Georgetown University, Washington DC 20057

*Current Address: National Institute of Standards and Technology, 20899

The high cost and the low catalytic activity of the anode catalysts are two major obstacles in the development of the direct-methanol fuel cell. Platinum (Pt)-based catalysts are considered the best anode catalysts for methanol electro-oxidation reaction and their catalytic activity is highly dependent on their surface structure. At nanoscale, the major determinants of the surface structure are the shape and size of the catalyst particles.  

This poster will outline the results of a detailed investigation on the shape and size dependent electro-catalytic activities of Pt nanoparticles. During the course of the investigation, simple synthetic procedures for the concomitant control of the shape and size of the Pt nanoparticles were developed and the trends in the electro-catalytic activity of the synthesized catalysts were correlated to the size and shape. The intermediate species generated during the methanol electro-oxidation reaction on the catalysts were studied by an in-situ tool; surface-enhanced infra-red absorption spectroscopy. Additionally, the first evidence on the enhancing effect of the capping polymer polyvinylpyrrolidone on the activity of Pt nanocatalysts for several electrochemical reactions was obtained.  The results of this overall investigation has interesting implications for the development of potential approaches, in fuel-cell related electro-catalysis research, that combine the effect of shape, size and capping polymer  to tune the activity of Pt electro-catalysts.