The enhanced catalytic activity of Au nanoparticles has recently attracted particular attention of scientists in various disciplines such as surface chemistry and heterogeneous catalysis. It was suggested that the Au-oxide (Au(III)) is at the interface of metallic Au nanoparticles and oxide supports and the Au(III) species contribute to stabilize Au nanoparticles on the surface. The formation of thin oxide films on gold coated quartz crystal electrode in 0.1 mol dm^-3 NaClO4 solution at pH 5.45 has been investigated by means of nanogravimetry using an electrochemical quartz crystal nanobalance which provides a new dimension for such studies. Anodic oxide film nucleation, growth and reduction processes were also investigated using cyclic voltammetry and potentiostatic chronoamperometric techniques. The oxide film nucleation kinetics was explained through a 3D nucleation mechanism with diffusion controlled growth and nucleation parameters were determined. Characterization of the oxide layer and the structural composition of the gold surface were examined by X-ray photoelectron spectroscopy and observed XPS spectrum were characteristic for Au(III) species. In addition to XPS, photoelectrochemical method was also used to characterize the surface. Anodically formed oxide film on gold acted as n-type semiconductor.

Kemija,Kemijsko inženjerstvo