Fabrication of Efficient Gold-Nickel-Supported Titania Nanotube Electrocatalysts for Sodium Borohydride-Hydrogen Peroxide Fuel Cells

Here we report the optimization of the fabrication conditions for AuNi bimetallic catalysts supported on self-ordered titania nanotube arrays (AuNi-TiO(2)ntb). A series of efficient AuNi-TiO(2)ntb catalysts with small amounts of Au in the range of 1.74 to 15.7 mu g(Au)center dot cm(-2) have been fabricated by anodization, electroless Ni plating, and galvanic displacement techniques. The electrocatalytic activity of the catalysts has been evaluated for BH4- ion oxidation in an alkaline medium using cyclic voltammetry and chronoamperometry. The performance of a NaBH4-H2O2 fuel cell with Ni-TiO(2)ntb and AuNi-TiO(2)ntb anode catalysts has been investigated at different temperatures. It was found that the electrocatalytic activity of AuNi-TiO(2)ntbs catalysts was improved remarkably when the Ni layer of 100 and 400 nm was used for the deposition of Au crystallites. The Ni-TiO(2)ntb catalyst generates the maximum power density values of ca. 85-121 mW center dot cm(-2) at a temperature of 25-55 degrees C, whereas the AuNi-TiO(2)ntb catalysts that have the Au loading of 3.07 and 15.7 mu g(Au)center dot cm(-2) achieve the power density values of ca. 104-147 and 119-170 mW center dot cm(-2), respectively, at a temperature of 25-55 degrees C.