TiO2 nanotube-supported amorphous Ni-B electrode for electrocatalytic oxidation of methanol

Amorphous Ni-B/TiO2 electrodes were successfully prepared by electroless plating. Highly ordered TiO2 nanotube arrays fabricated by anodic oxidation were employed as substrate and loaded with Ni-B alloy by electroless plating. The phase formation, microstructures and catalytic activity of electrodes were investigated by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and electrochemistry analyzer, respectively. The results show that Ni-B/TiO2 electrodes with an average particle size of 200 nm present a typical amorphous structure of Ni and B, and have high catalytic activity for methanol electrooxidation in alkaline medium. The peak current density in cyclic voltammetry (CV) curves reaches 360 mA cm(-2) in the solution with 0.5 mol L-1 methanol, much higher than that of Ni-B/Ti electrode. With the methanol concentration increasing to 1.5 mol L-1, the peak current density increases to 488 mA cm(-2), after which it remains almost constant. The Ni-B/TiO2 electrodes are relatively stable according to catalytic lifetime test; the peak current density remains 72.1% of the original value after 1300 times cycles. The amorphous Ni-B/TiO2 electrode should be a promising candidate for direct methanol fuel cell. (C) 2010 Elsevier B.V. All rights reserved.