Nanostructured metal films: Fabrication and catalytic properties

Thin nanostructured films consisting of monodispersive and amorphous Cu, Ni, or Pd nanoparticles were prepared by means of laser electrodispersion technique. These films were deposited on dielectric (thermally oxidized silicon) or semiconductor (naturally oxidized Si) supports, and the resulting particle surface density was closely controlled by the time of deposition. The nanoparticle size was 5 nm for Cu, 2.5 nm for Ni, and 2 nm for Pd. In all cases, the relative particle size dispersion was less than 10%. The most important common feature of the fabricated catalysts is their unusually high activity, which has been observed in several test reactions including chlorohydrocarbon conversions (Cu and Ni) and hydrogenation (Ni and Pd). The observed strong dependencies of the catalytic activity on the particle surface density and on the nature of the support clearly indicate that alongside with small particle size and their amorphous state, inter-particle interactions or particle interaction with the support play decisive role in determining the catalytic activity.