Nano-structured Pt-Cr anode catalyst over carbon support, for direct methanol fuel cell

摘要

In this study, several lands of carbon were used as the support for the Pt-based catalyst of the direct methanol fuel cell (DMFC). Mesoporous carbons with large BET surface area and a commercial carbon were used as the support for the anode catalyst. The maximum current densities of the catalysts were compared by cyclic voltammogram. The catalyst supported on Vulcan XC-72, the commercial carbon support, showed the highest catalytic activity because of its high electric conductivity in spite of small BET surface area. Transition metals such as Cr, Mn, Y, or Zn were impregnated simultaneously with a Pt precursor on Vulcan XC-72, respectively, and then the catalytic activity was tested. The Pt-Cr/C catalyst showed the highest catalytic activity among this catalyst series, and was more active than the Pt/C catalyst. Furthermore, in order to improve the activity of the Pt-Cr/C catalyst, sintering of active metals by thermal reduction during the preparation should be avoided. Therefore, alkaline aluminum leaching method was applied for the purpose of decreasing the particle size of the active metals by reducing the sintering of Pt and Cr. Aluminum precursor was introduced together with Pt and Cr precursors into the commercial carbon support in the preparation process. After reduction of the sample, aluminum species were selectively leached out. The catalyst showed a much improved activity as expected and characterized by H_2 chemisorption and TEM analyses.