Loreta Tamasauskaite-Tamasiunaite

Investigation of Electrocatalytic Activity of the Nanostructured Au-Cu Catalyst Deposited on the Titanium Surface towards Borohydride Oxidation

Sodium borohydride (NaBH4) is characterized by interesting options for electrochemical power generation as a source of hydrogen or anodic fuel for direct borohydride fuel cells (DBFC) and batteries. In recent years the DBFCs are being developed especially for portable power supply. An active search for costeffective catalysts is still in progress. A simple way for fabrication of the nanostructured Au(Cu)/Ti catalysts by a two-step process which involves electroless copper deposition followed by a spontaneous Au displacement from the chloro-complex solution is presented herein. The morphology and composition of fabricated catalysts were characterized using field-emission scanning electron microscopy (FESEM) and energy dispersive X-ray spectroscopy (EDAX). The electrochemical behavior of the fabricated nano-Au(Cu)/Ti and Cu/Ti catalysts was examined by means of cyclic voltammetry (CV). The electrocatalytic activity of the catalysts towards the oxidation of BH4 ions was compared with that of bare Au electrode. Well-adherent gold-coated copper films (Au/Cu), with particles of a few nanometers in size have been fabricated on the titanium surface by immersion of Cu/Ti electrode into the gold-containing solution for various time periods as testified in Fig. 1. Electroless copper deposited on the titanium surface produced a layer of polycrystalline copper with the average size of crystallites ca. 1 μm. Notably the thickness of the electroless copper layer was about 1.5 μm. The Au particles appear as bright crystallites of cubic form of 10 up to 50 nm in size and are homogeneously dispersed on the copper surface (Fig. 1, b-d).