Investigation of Carbon Supported Nanostructured PtAu Alloy as Electrocatalyst for Direct Borohydride Fuel Cell

Carbon supported bimetallic PtAu electrocatalysts for sodium borohydride electrooxidation are prepared by a modified citrate stabilized NaBH4 reduction process at different pH and temperature values. The physical properties of the materials are characterized by X-ray diffraction spectroscopy, energy dispersive spectrometry, X-ray photoelectron spectroscopy and transmission electron microscopy. Nano sized electrocatalysts have narrow size distributions and are uniformly dispersed on the surface of carbon support. Electrochemical performances of catalysts for sodium borohydride electrooxidation are tested with 25 cm(2) single fuel cell. The highest performance is obtained at a peak power density of 161 mWcm(-2) with 20 wt. % PtAu/C catalyst of 7.03 nm. Impact of the fuel cell operation parameters including concentration of NaBH4, flow rates of oxidant and fuel, and fuel cell operation temperature are investigated. The best operation parameters are obtained at 1 M NaBH4 concentration, 3 cm(3) min(-1) NaBH4 flow rate, 0.2 dm(3) min(-1) oxygen flow rate and 65 degrees C fuel cell temperature.