ON THE CONDITIONS AND MECHANISM OF PTO2 FORMATION IN THE PHOTOINDUCEDCONVERSION OF H2PTCL6

X-ray photoelectron spectroscopy (XPS) and UV-visible absorption spect roscopy were used to investigate the conditions and mechanism of PtO2 formation during the photoinduced conversion of PtCl62- in a Pt/CdS aq ueous dispersion. The experimental results indicate that the critical factors affecting PtO2 formation are the pH value of the dispersion an d the initial H2PtCl6 concentration. At pH13 and an initial H2PtCl6 co ncentration of 10(-2) M, the deposits detected on the illuminated Pt/C dS surface were PtO2 and Pt(OH)2. It is suggested that PtO2 is formed by the photoinduced oxidation of the hydrolysate of PtCl62- (i.e. Pt(O H)4Cl22-) on the Pt/CdS surface. The formation of oxygen was also obse rved in the process.