(58af) Combination of Sea and ED Methods for Preparation of Active Bimetallic Catalysts for Direct Methanol Fuel Cells

Direct methanol fuel cells (DMFCs) have received widespread attention because of their potential applications in transportation and portable electronic devices. Platinum (Pt) catalysts are effectively able to catalyze the oxidation of methanol to carbon dioxide in this system. The main drawback for Pt-based catalysts is that the CO intermediate chemisorbs strongly on Pt surface; even traces of CO will lead to a severe poisoning of Pt catalysts, which prevents further catalyst turnovers. From previous studies, bimetallic catalysts composed of platinum (Pt) and a second metal such as Ru or Ni are more active for the oxidation of methanol compared to catalysts composed only of Pt. In addition, the stability and activity of catalysts depend directly on the architecture, which is greatly affected by both the composition and preparation methods [1]. In this study, nanometer sized Pt-Ru and Pt-Ni particles on a carbon support are prepared by combining the methods of strong electrostatic adsorption (SEA) and electroless deposition (ED).

The method of SEA has been used to form supported Pt nanoparticles with high dispersion and narrow size distributions. Catalysts prepared by SEA are then used as seed nuclei for addition of a secondary metal (Ru or Ni) using Electroless Deposition (ED). Thus, two series of carbon- supported bimetallic catalysts were prepared containing controlled and variable coverages of Ru or Ni on Pt surfaces, which were then characterized and evaluated for methanol oxidation reactions. These sets of catalysts show higher activity towards methanol oxidation in comparison to the analogous, commercial catalysts.

References

1. Ehteshami, S.M.M. and S.H. Chan, A review of electrocatalysts with enhanced CO tolerance and stability for polymer electrolyte membarane fuel cells. Electrochimica Acta, 2013. 93: p. 334-345.