Education

B.S., Chemical Engineering (2008)
North Carolina State University

Research Project: Effects of particle size on stability and oxide growth in platinum dissolution studies of PEMFCs

Research Summary: Platinum dissolution is an effect of potential cycling that limits fuel cell lifetime in automotive applications. Several mechanisms and models have been developed to explain platinum dissolution. Continued progress in these areas will help develop mitigation techniques and be applicable to studies in similar areas.

The goal of this work is to analyze the effects of surface energy on platinum stability throughout the lifetime of a PEMFC for different particle sizes. By utilizing the PDF method, particle size effects will be monitored as a function of potential cycles. Preliminary experiments show how bond strain changes as a function of particle size for particles ~2 – 10 nm in diameter. This study will be extended to subnanometer platinum particles.

Additionally, this project will incorporate the modeling of oxide growth on platinum into current dissolution studies. We aim to provide a fundamental, physical model that describes long potential holds, oxygen penetration in the lattice, and incomplete coverage of surface oxides. Model results will be verified with experimental data.

Meeting both goals of the project will contribute to a total dissolution model, providing insight to conditions which minimize platinum loss. Analytical tools that will be used include a high energy x-ray synchrotron to obtain PDF data, standard crystallographic methods, and electrochemical measurements.