Thesis (Ph.D.)--Chulalongkorn University, 2015

This work was carried out to study the effect of metal oxide (MO2) on activity and stability of Pt-Co/C electrocatalyst. The investigated parameters were types of the metal oxides (TiO2, MoO2, and CeO2) and the loadings of the metal oxide (0.03 – 0.45 mg/cm2) and also compared the effect of TiO2 prepared by chemical vapor deposition and commercial TiO2. The experiment reported that the types of the metal oxide, quantity did not influence to the structure and the morphology of Pt-Co/C electrocatalyst. For the test of ORR activity in acid electrolyte and in PEM fuel cell, it was found that the addition of CeO2 and MoO2 provided the negative result, while adding the commercial TiO2 by 0.03 up to 0.06 mg/cm2 could increase the ORR activity test. The kinetic current density and current density at 0.6 V of the Pt-Co/C electrocatalyst were around 8.05 mA/cm2 and 435 mA/cm2, respectively when approximately 0.06 mg/cm2 of TiO2 were added. For the TiO2 prepared by the chemical vapor deposition technique, it provided a higher rate up to 20.24 and 454.80 mA/cm2, respectively. Regarding the stability, the CeO2 and MoO2 could not improve the stability of the Pt-Co/C electrocatalyst, while the TiO2 gave the positive effect.