| Summary: | 博士 === 國立中央大學 === 物理學系 === 103 === In this thesis, the electrocatalyst nanocomposites, prepared from metal
nanoparticles and graphene, have been studied for performance of their
electrocatalysis. There are two synthetic methods employed in preparation: one is
the green synthesis in 2-hydroxyethanaminium formate ionic liquid with microwave
assistance; the other is the hydrothermal synthesis with metal precursor and modified
graphene in one pot. The ionic liquid and microwave assisted synthesis produced
cubic Pt nanoparticles on graphene sheet (cubic Pt/G), which were evaluated with
performance on methanol oxidation reaction (MOR). The one-pot hydrothermal
method produced the PDDA-modified graphene with metal nanoparticles on it
(PtAu/PDDA-G, PtNi/PDDA-G, PtFe/PDDA-G or Ni-NiO/PDDA-G). These
nanocomposites were examined with transmission electron microscopy (TEM) for
morphology and also for nanoparticle sizes. Nanoparticles on the cubic Pt/G are
about 5-20 nm in size and those of PtM/PDDA-G and Ni-NiO/PDDA-G are about ~5
nm in size. From the X-ray diffraction analysis, nanoparticles on the PtNi/PDDA-G
are a single alloy, to apply to the MOR electrocatalysis. The results of ESCA
analysis revealed that nanoparticles on the PtNi/PDDA-G are in elemental
environments on the graphene surface. The thermal gravimetric analysis (TGA) was
employed for evaluation of amounts of the metal deposited on graphene.
As electrocatalyst, the MOR performance of cubic Pt/G is no better than that of
commercial Pt on carbon (60wt% Pt/C). However, the anti CO-poisoning capability
and the unit mass performance of cubic Pt/G is better those of 60wt% Pt/C. The
PtNi/PDDA-G is one of the candidates for anode electrocatalysis for use in direct
methanol fuel cells. The Ni-NiO/PDDA-G is also an candidate for fuel cell cathode
electrocatalysis in oxygen reduction reaction (ORR) utilization. In addition, the formic
acid oxidation reaction utilizating of PtAu/PDDA-G was also investigatied in this
thesis.
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