NSF Award
0078635
This Small Business Innovation Research Phase II project addresses the development of highly dispersed Pt-Mo electrocatalysts for application as anodes in proton exchange membrane (PEM) fuel cells. Alternative anode electrocatalysts remain a critical development area for the cost reduction and performance enhancement of PEM fuel cells operating on reformate hydrogen fuel. Specifically, there is a need for catalysts that are tolerant to reformate by-products such as CO. Supported Pt-Mo is a leading candidate for the next generation of these catalysts. The Phase I research successfully produced highly dispersed Pt-Mo catalysts supported on Vulcan XC-72 using two distinct methods. The catalysts produced by both methods show excellent hydrogen oxidation characteristics in 0.5 M H2SO4. The performance of these materials in 100 ppm CO/H2 indicated high activity but did not, however, show the degree of CO-tolerance expected on the basis of results from bulk Pt-Mo alloys. These findings were surprising in light of voltammetric evidence that showed electrochemical interaction between Mo and Pt.<br/><br/>Phase II of this effort will develop a more comprehensive understanding of the nature of Pt-Mo interactions. The results from the Phase I research at T/J suggest that the promotion of enhanced H2 oxidation at lower potentials in CO/H2 fuel streams is critically dependent upon the nature of the Pt-Mo interaction. We intend to examine the influence of surface composition/coverage of Mo on solid Pt electrode surfaces in the presence of CO/H2 fuel streams as a function of potential using a rotating disk electrode (RDE) system. These fundamental studies of solid electrode surfaces will identify the basis of CO-tolerance. Based on these results, we will pursue rational development of supported Pt-Mo catalysts with the appropriate surface chemistry and structure using three novel dispersion methods. As a part of this work, we will conduct in-depth physicochemical characterization of the catalysts as well as more comprehensive electrochemical analysis. We intend to produce prototype membrane electrode assemblies (MEAs) for testing in fuel cells. In addition, we will supply catalyst materials for external evaluation by leading catalyst manufacturers. These companies have committed over $840,000 in follow-on funding for this SBIR project.<br/><br/>Low cost CO-tolerant catalysts developed under this SBIR project will enable the commercialization of high performance PEM fuel cells operating on reformed hydrogen. Reducing catalyst costs addresses a key obstacle hindering the commercialization of PEMFCs for vehicle propulsion and off-grid electric power generation.
