A modified electrode with vanadium hexachloroplatinate (VptCl(6)) film has been fabricated directly from the mixing of V2+ and ptCl(6)(2-) ions, and its electrochemical behavior was investigated. The deposition of a VptCl(6) film occurred when pt(IV)Cl(6)(2-) was electrochemically reduced to pt(II)Cl(6)(2-) and V3+ to V2+. The electrochemical quartz crystal microbalance (EQCM), ultraviolet-visible absorption spectroscopy, stopped-flow, chronoamperometry, and cyclic voltammetry techniques were used to study the deposition and growth mechanism of the above film. In the EQCM studies, the reversibility of the vanadium (II/III) hexachloroplatinate film during cycling and the corresponding frequency change was found to be good, and the V2+ ion exchange obviously occurred in the redox couple. For the surface morphological analysis, the film was further electrochemically deposited on a transparent semiconductor indium tin oxide (ITO) electrode for scanning electron microscopy and atomic force microscopy studies. It was found that the deposited VPtCl6 film formed as a film with platinum and vanadium particles on ITO. To validate the electroanalytical properties, a VPtCl6-modified glassy carbon electrode was applied for the electrocatalytic reduction of the NAD(+) (beta-Nicotinamide adenine dinucleotide) and sulfur oxoanions, and the results showed a quite effective electrocatalytic reduction for the corresponding substances. (C) 2008 The Electrochemical Society.