Electro-oxidation of hydrazine on gold nanoparticles supported on TiO2 nanotube matrix as a new high active electrode

Au/titanium dioxide nanotubes (Au/TiO2-NTs) catalysts are prepared by a simple method using galvanic deposition of gold nanoparticles on TiO2-NTs as support. TiO2-NTs are fabricated by anodizing titanium foil in a dimethyl sulfoxide (DMSO) fluoride-containing electrolyte. Scanning electron microscope and energy-dispersive X-ray spectroscopy results indicate that nanotubular TiO2 layers consist of individual tubes of about 50–80 nm diameters and gold nanoparticles with a size range of 30–40 nm are well-dispersed on the surface of TiO2-NTs support. The electro-catalytic properties of Au/TiO2-NTs catalysts toward electro-catalytic oxidation of hydrazine are investigated by cyclic voltammetry. Compared to flat gold electrodes, Au/TiO2-NTs catalyst shows much higher electrochemical activity. This may be attributed to the uniform dispersion of gold nanoparticles on TiO2-NTs, smaller particle size and unique properties of TiO2-NTs support. In addition, the mechanism of hydrazine electrochemical oxidation catalyzed by Au/TiO2-NTs is investigated.

Cyclic voltammograms for Au/TiO2-NTs/Ti and bare gold electrodes in 0.1 M phosphate buffer–0.00085 M hydrazine aqueous solution. The current density for hydrazine oxidation on Au/TiO2-NTs/Ti electrode is greater than that observed for gold electrode. This result may also be attributed to the larger specific surface area of the Au/TiO2-NTs/Ti electrodes.Figure optionsDownload high-quality image (109 K)Download as PowerPoint slideResearch highlights▶ Au/TiO2-NTs/Ti catalysts with highly porous structure and excellent electro-catalytic property have been successfully fabricated by a two-step process consisting of anodizing titanium followed by electroplating of gold. ▶ Due to the uniform dispersion of gold nanoparticles on TiO2-NTs, smaller particle size and unique properties of TiO2-NTs support, Au/TiO2-NTs/Ti electrode have High current density and good stability toward electro-oxidation of hydrazine. ▶ The oxidation kinetic of hydrazine on Au/TiO2-NTs/Ti electrode was studied and results indicated that the oxidation process is diffusion controlled. ▶ This study provides a promising route for the simple, facile and cost-effective synthesis of Au/TiO2-NTs/Ti catalysts and the as-synthesized catalysts show great prospect in the applications of fuel cells.