Metal Oxide/Pt Based Nanocomposites as Electrocatalysts for OxygenReduction Reaction

Fuel cells have been hailed as an important power source for the future because of their highenergy conversion efficiency and low environmental pollution. Fuel cells are attractive powersources for both stationary and electric vehicle applications due to their high conversionefficiencies and low pollution. Many difficulties have prevented the widespread usage of fuelcells including high content of high cost platinum as the most familiar electro-catalyst, oxygensluggish kinetics caused by CO-like species poisoning effect and the formation of –OH species at+0.8 V, which inhibits further reduction of oxygen.Recently, much of the research work isfocused on the system of combining metal oxides to reduce the catalytic loading of the materials(cost reduction), to improve the electrochemical activity for the cathodic reaction and to increasestability.In this study, Pt catalyst was precipitated on Vulcan XC-72R containing 10 wt.% NiOand CoO using NaBH4 as a reducing agent. The prepared catalyst was heat-treated at 400-700 ○C.XRD and SEM characterizations were carried out to determine the crystalline phase, particle sizeand morphology of the catalysts. XRD patterns of sample showed peaks characteristic of Pt(111), (200), (220) and (311). The diffraction peaks are also observed for cubic phases of CoOand NiO. The electrocatalytic activity of electrocatalysts was examined by using cyclicvoltammetry techniques. The enhanced electrocatalytic performance and the long-term cycledurability of electrocatalyst are attributed to the strong interaction between Pt, NiO and CoO andthe formation of small Pt crystals. Cyclic voltammetry and linear sweep voltammetry wererecorded to evaluate ORR performance and electrochemically stability

کلیدواژه ها:

Fuel cells ، Oxygen Reduction Reaction ، Electrocatalysts ، Metal Oxide ، Platinum