| dc.description.abstract | Platinum is the most effective electrocatalysts for use in Direct Methanol Fuel Cell (DMFC), both anode and cathode, because of its’ high catalytic activity for methanol oxidation and oxygen reduction reactions (ORR). Another advantage for using platinum is it has very high stability and good corrosion resistant under acidic operating medium. Even though other metals have similar activity capabilities but fail to perform in acidic condition. However, platinum is too expensive for use in DMFC and finding an alternative much cheaper catalyst is desirable towards the realization of DMFC. Another problem in using platinum at the cathode is the methanol crossover problem. Methanol crossover to the cathode created both over-potential and active site poisoning problems when Pt is used. The search for more active and less expensive non-platinum based catalysts for oxygen reduction reaction (ORR) is one of the most important issues towards the commercialization of DMFC.
This thesis explores the possibility of using palladium, instead of platinum, as the basic component of the DMFC cathode catalyst. In order to boost the performance of Pd, Co was added to form a binary catalyst (PdCo/C). Furthermore, ternary PdCoW, PdCoAu and PdCoMo catalysts were also studied. The effect of preparation method, activation method and catalyst formulations towards ORR activity and methanol tolerance were explored in this thesis. Catalyst performance were studied using Rotating Disk Electrode (RDE) and Cyclic Voltammetry (CV). Results in this study revealed that PdCo based catalyst have good tolerance in methanol. The ORR activity, with and without added methanol, decreases in the following order: PdCoMo/C > PdCoAu~PdCoW > PdCo. Futhermore, all PdCo based catalysts have higher activity than commercial Johnson Matthey Pt/C catalysts in the presence of methanol. Catalysts prepared with Pd(CH3CO2)2 as the Pd precursor have better activity over PdCl2 precursor.
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