Synthesis And Characterization Of Platinum Group And Their Oxide Nanoparticles By Bydrothermal Method

The hydrothermal syntheses of the nanoparticles of platinum group metals and their oxides were studied and the effect of reaction parameters on the sizes, morphologies and dispersions was investigated.PtO₂ nanoparticles were prepared by hydrolytic condensation of H₂PtCl₆ in alkaline aqueous solution with cetyltrimethylammoniumbromide (CTAB) as a stabilizer in the presence of appropriate amount of NaAc by means of hydrothermal method. The products were characterized by UV-vis spectroscopy, TEM and XRD. The effects of reaction parameters on PtO₂ nanoparticles were investigated. Rod-like PtO₂ nanoparticles with a length of 1.5μm, a cross diameter of 0.4μm, and the aspect ratio of 3.75 were synthesized under the condition of a molar ratio of 30/3/1 of NaAc/CTAB/H₂PtCl₆. The formation mechanism of the rod-like PtO₂ nanoparticles was explored preliminarily.The hydrothermal synthesis of PdO nanoparticles was studied by hydrolytic condensation of H₂PdCl₄ with PAA as a stabilizer in alkaline environment and the products were characterized by UV-vis spectroscopy, TEM and XRD. The effects of the temperature, the amount of PAA and NaOH on PdO nanoparticles were investigated. PdO nanoparticles with some morphologic aspect were synthesized at 100°C for 10h under the condition of a molar ratio of 40/15/1 of PAA/NaOH/H₂PdCl₄ and the average diameter was about 9.1nm.The PtO₂ nanoparticles were synthezed with hydrolytic condensation of H₂PtCl₆ in the presence of PVP and CTAB by means of hydrothermal method. The products were characterized by UV-vis spectroscopy, TEM, XRD and XPS. The effects of CTAB, NaOH and PVP on the preparation of PtO₂ nanoparticles were investigated. The results showed that ball-chain PtO₂ nanoparticles with uniform size, well dispersion and an average diameter of 40.8 nm were obtained at 120°C for 6 h under the condition of a molar ratio of 1/5/12/100 of H₂PtCl₆/CTAB/NaOH/PVP.Without any reducing agent, the Pd nanoparticles was synthesized with octadecyl dimethyl benzylammonium chloride (1827) as a stabilizer by decomposition of H₂PdCl₄ via a hydrothermal route. The products were characterized by UV-vis spectroscopy, TEM and XRD. The effects of the reaction time, the amount of 1827 and KOH on Pd nanoparticles were investigated. Polyhedral Pd nanoparticles with an average diameter of 26.5 nm were obtained at 160°C for 10 h under the condition of a molar ratio of 10/4/1 of 1827/KOH/H₂PdCl₄.