Self-ordered titania nanotubes and flat surfaces as a support for the deposition of nanostructured Au–Ni catalyst: Enhanced electrocatalytic oxidation of borohydride

Gold aggregates with particle size of a few nanometers have been fabricated on the anodized titania nanotube arrays and flat surfaces by a two-step process which involves nickel electroless deposition followed by spontaneous galvanic displacement of Ni by Au from its chloro-complex solution. The structure, morphology and composition of the fabricated catalysts have been characterized using scanning electron microscopy and energy dispersive X-ray analysis. The catalytic activities of the nanostructured Au(Ni) catalysts preformed on the TiO2 nanotube arrays and flat surfaces have been investigated towards borohydride oxidation in an alkaline medium by cyclic voltammetry and chrono-techniques. The nanostructured Au(Ni) catalysts on the titania nanotube arrays and flat surfaces exhibit enhanced electrochemical activity and stability towards oxidation of BH4− ions in an alkaline medium as compared to that of bulk Au.

► Self-ordered titania nanotubes and flat surfaces as a support for catalysts. ► Electrocatalysts for the oxidation of borohydride. ► Catalyst fabrication by galvanic displacement of nickel layer by gold enables growth of nano-sized metal particles. ► Nano-Au(Ni)/TiO2-NTs and nano-Au(Ni)/TiO2-flat are efficient electrocatalysts for borohydride oxidation.