Pt/MnO₂ nanostructured catalysts were synthesized by a facile method. Effects of reaction conditions on the particle size, size distribution and dispersity of Pt nanoparticles were studied by changing the reduction time, the reaction temperature, the amount of polyvinylpyrrolidone (PVP) and the loading amount of Pt. A series of Pt/MnO₂ nanostructured catalysts with different MnO₂ supports and Pt loadings were synthesized under optimal conditions. The as-prepared MnO₂ supports and Pt/MnO₂ nanostructured catalysts were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Experimental results showed that Pt nanoparticles of small size and high dispersion were obtained on the MnO₂ supports when the reduction time, the reaction temperature, the amount of PVP was 1 h, 80 ℃, and n(PVP)∶n(Pt)＝20∶1, respectively. The particle size of Pt nanoparticles first increases, and then decreases with increase of the Pt loading. The loading process of Pt nanoparticles did not influence the crystal form and morphology of the MnO₂ supports. The particle size of Pt nanoparticles was not influenced but the distribution density of Pt nanoparticles was influenced by varying MnO₂ support.

Key words: Pt nanoparticle, particle size, MnO₂ support, Pt/MnO₂ nanostructured catalysts