Preparation and characterization of metal nanoparticles on a diamond surface

The deposition of metal nanoparticles (such as Ag, Cu, Au, Pd, and Pt) on boron-doped, polycrystalline diamond thin films grown on silicon substrates was investigated using Raman spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction. Nanometer-size metal particles with preferred crystalline textures can be spontaneously deposited on the diamond thin film after a simple immersion in an acidic solution containing metal ions or metal complex ions. The size and distribution of metal deposits can be controlled by adjusting the metal ions concentration, the solution acidity, and the deposition time. The diamond/silicon interfacial ohmic contact was found to be the critical factor for achieving the observed spontaneous metal deposition on the diamond surface. Significant enhancement of hydrogen evolution activity was observed on a diamond electrode modified by 9% coverage of Pd nanoparticles. The results demonstrate a novel route for depositing nanometer-size metal catalysts on a highly corrosion resistant and dimensionally stable polycrystalline diamond support.