Thesis (Ph.D.)--Chulalongkorn University, 2012

The effort to develop the PEM fuel cell electrocatalyst by lowering the precious metal loading in the composition has been extensively addressed. The carbon supported core – shell structure catalyst structure is considered to be the interesting alternative for improving the catalyst properties and stability. In the preliminary stage of this work, the preparation of Ni[subscript core] – Pt[subscript shell]/C was studied. The results suggested that the synthesis method and type of stabilizer used in the synthesis process had an effect on the metal content in the composition, particle size and the EAS of the catalyst. For the synthesis of Ni[subscript core] – PtRu[subscript shell]/C catalyst with modified polyol method, the parameters concerning in the synthesis were investigated by FCC – 2⁴ experimental design. The results indicated that the atomic ratio of platinum to ruthenium, the mole ratio of Ni precursor to the PVP stabilizer, the reduction temperature for the PtRu alloy shell formation step and the interaction between the mole ratio of Ni precursor to the PVP stabilizer and the mole ratio of Ni precursor to the PVP stabilizer affected the EAS of the synthetic catalyst. In addition, heat treatment of the Ni core particle before adding PtRu alloy shell layer could improve the activity of the Ni[subscript core] – PtRu[subscript shell]/C. The durability study of the heat – treated Ni[subscript core] – PtRu[subscript shell]/C by potential cycling technique showed the higher stability compared to the commercial Pt/C.