Platinum-Ruthenium Mixed Metal/Metal Oxides: ReaxFF for Fuel Cell Application


The best direct methanol fuel cell is currently used Pt-Ru alloys on a proton exchange membrane. In hydrogen fuel cell Ru also significantly improves the CO tolerance of Pt. However, there are still controversies on the nature of the promotion mechanism: a potential-dependent XPS confirmed the presence of Ru oxide species [RuO2 and RuO3] in the PtRu(1:1) electrode at potentials relevant to fuel cell anode catalysts (where Pt remains metallic) and proposed that Ru acts as oxygen transfer promoting agent; another XPS study, however, suggested that the presence of a metallic Ru is a prerequisite for active catalysts and RuOx species act as a catalytic de-enhancer rather than as a promoter.
 
Little is also known about the optimal Pt-Ru surface concentration, Pt-Ru distribution and the surface structure of active Pt-Ru electrocatalysts. We are currently developing a reactive force field (ReaxFF) for Pt/Ru alloys and their oxides to generate plausible surface structures of Pt-Ru electrocatalysts that will be used in further quantum mechanical calculations of reaction mechanisms.

Personnel: Dr. Yun-Hee Jang

This project is in collaboration with Dr. Adri van Duin