Electrodeposition of Pdnanoparticles on C@TiO2 nanoarrays: 3D electrode for the direct oxidation of NaBH4

Abstract

A newly designed and fabricated electrode with three-dimensional structures is reported. The electrode consists of a conducting nanoarray substrate and Pd nanoparticles. The substrate is an array of TiO₂ nanowires with a carbon coating layer prepared via a thermal evaporation method. Pd nanoparticles were electro-deposited on the substrate surfaces by the potentiostatic pulse method. The morphology of the electrode is observed by scanning electron microscopy and transmission electron microscopy, and its structure is analyzed using an X-ray diffractometer. The catalytic performance is evaluated by cyclic voltammetry and chronoamperometry. The electrode exhibited excellent catalytic performance for NaBH₄ electro-oxidation. The current density for NaBH₄ electro-oxidation at the electrode reported in this work (524 mA mg⁻¹) is about 5 times of that at conventional Pd/C (100 mA mg⁻¹). This enhanced performance is likely to be due to the improved mass transport of NaBH₄, good electronic conductivity and high Pd utilization of the electrode.