A series of narrowly distributed nanoparticles with different sizes of platinum oxide stabilized by polyvinylpyrrolidone (PVP) were synthesized by hydrolytic decomposition of platinum chloride. The as-synthesized nanoparticles were characterized by UV-vis, TEM, and XPS examination. Studies on the parameters influencing the size of the as-synthesized platinum oxide nanoparticles were carried out. The pH of the solution was demonstrated to be the main factor affecting the particle diameter. The particles size also decreased with the increasing molar ratio of stabilizer (PVP):PtCl4. The influence of the concentration of sodium acetate on the rate of hydrolytic decomposition and the condensation reaction was studied. It was found that increasing the concentration of sodium acetate increased the rate of the condensation reaction nearly linearly. (c) 2006 Elsevier Inc. All rights reserved.