| Summary: | 碩士 === 國立成功大學 === 化學工程學系碩博士班 === 98 === A new type of catalyst support, hollow spheres of N-doped mesoporous carbon, was synthesized via pyrolysis of silica hollow spheres/polyaniline composite. The surface morphology and the size of N-doped mesoporous carbon particles was found to be influenced by altering the ratio of aniline/silica. The ratio of N/C was controlled by changing the composition of aniline and APS, and the temperature of carbonization. A possible structural evolution of the N-doped mesoporous carbon is proposed based on the results obtained from a variety of characterization techniques. The sample P850 appears the more appropriate property for application in fuel cells.
N-doped carbon-supported platinum nanocatalyst was prepared by chemical reduction using ethylene glycol. The images of TEM showed that platinum nano-particles are well-distributed on the surface of the N-doped carbon support. ESCA showed that pyrrolic, pyridinic and Quaternary types of nitrogen atoms existed in the functionalized carbon. The electrochemical active surface area is 87 m2/g Pt which is 8 times higher than that (11 m2/g Pt) of the raw hollow mesoporous carbon spheres.
In the direct methanol fuel cell operation, we obtained a power density of 25.2 mW/cm2 by using the platinum supported on hollow spheres of N-doped mesoporous carbon (P851) as the cathode, which is 19% higher than E-TEK 20%Pt/C (21.2 mW/cm2), and 2.7 times higher than the cell by using hollow mesoporous carbon spheres supported Pt catalyst (9.2 mW/cm2) as the cathode. In comparison, the power density of the cell by using the platinum reduced in base environment supported on hollow spheres of N-doped mesoporous carbon which was after calcination (P852(cal.)) as the anode is 24.0 mW/cm2. The successful advancement in this N-doped nanostructured carbon for fuel cell catalyst presents a significant achievement in both the scientific and engineering fields.
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