Synthesis and characterization of ruthenium nanoparticles

We report work on the synthesis of ruthenium nanoparticles in a polymer support and, for the first time, characterization of the particles in this support is performed using the scanning tunneling microscope (STM). Ruthenium nanoparticles are prepared from the alcoholic reduction of Ru+3, in the presence of 10 nm polyvinyl pyrrolidone nanoparitcles (PVP). UV visible absorption measurements are used to track the stepwise reduction of Ru +3 into Ru+2, Ru+1 and Ru0. Ru+3 is characterized by a broad absorption spectra between 300 and 470 nm. The maximum absorption wavelength changes from 357 nm to 346 nm upon the reduction of Ru+2 to Ru+1. The spectrum of the ruthenium nanoparticles is characterized by a high baseline, associated with light scattering by the nanoparticles, and a broad absorption band below 350 nm. The PVP nanoparticles are changed into rods in the synthesis process. The PVP derived rods are about 46.1 nm long and 21.5 nm in diameter. Ruthenium nanoparticles are detected on the rods surfaces in scanning tunneling electron microscopy measurements. Electron tunneling current measurements as a function of bias voltage of the particles on the PVP surface reveal three independent bands associated with the stepwise ionization of Ru into Ru+, Ru+2 and Ru+3. No significant results about the mechanism by which PVP particles prevent the agglomeration of ruthenium nanoparticles was found in FTIR measurements.