Metal Oxide/Pt Based Nanocomposites as Electrocatalysts for Oxygen Reduction Reaction

Fuel cells have been hailed as an important power source for the future because of their high energy conversion efficiency and low environmental pollution. Fuel cells are attractive power sources for both stationary and electric vehicle applications due to their high conversion efficiencies and low pollution. Many difficulties have prevented the widespread usage of fuel cells including high content of high cost platinum as the most familiar electro-catalyst, oxygen sluggish 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 is focused 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 increase stability.In this study, Pt catalyst was precipitated on Vulcan XC-72R containing 10 wt.% NiO and 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 size and 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 CoO and NiO. The electrocatalytic activity of electrocatalysts was examined by using cyclic voltammetry techniques. The enhanced electrocatalytic performance and the long-term cycle durability of electrocatalyst are attributed to the strong interaction between Pt, NiO and CoO and the formation of small Pt crystals. Cyclic voltammetry and linear sweep voltammetry were recorded to evaluate ORR performance and electrochemically stability.