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Abstract
The goals of this research were to prepare cabon supported Pt
and Pt- Ru catalysts for methanol fuel cell and for
oxidation of acetaldehyde. The oxidation reaction of
acetaldehyde were carried out with a continous fix bed reactor
at 40℃and 520psig. Both fresh and the reacted catalysts were
characterized by CO chemisorption , fast Fourier transform
infrared (FFT-IR) spectroscopy, temperature programmed
reduction (TPR), atomic absorption spectroscopy (AA), and
extended X-ray absorption fine structure (EXAFS). Together
with the reaction and characterization results, the following
conclusions were obtained regarding the structure and catalytic
performance of the catalysts：
(1) The despersion of the catalyst was increased with decreasing
the amount of water used for the preparation because of the
hydrophorbic properties of carbon supports.
(2) The catalysts with the highest metal dispersion have the
metal particles with morphology characterizing three dimension.
(3) For the fresh carbon-supported Pt catalysts, the highest Pt
dispersion is the catalyst reduced at 200℃, the 300℃ in the
middle, the lowest is the catalyst reduced at 450℃.
However, the catalyst reduced at 300℃ presents the
best performance. The results is the compromise between Pt
metal dissoluted, metal migration and oxidation of metal
particles. (4)During the oxidation reaction, only
surface has been oxidized. (5)The main difference of
the catalytic performance between the Pt-Ru/C catalyst
with and without bimetallic interactions is over-oxidation
reaction ; the catalysts without bimetalic interactions has more
water yield.
(6) The addition of Ru to the Pt catalysts has no improvement in
metal dissoluted problem.
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