Palladium Nanostructures and Nanoparticles from Molecular Precursors on Highly Ordered Pyrolytic Graphite

Abstract

Nanostructures and nanoparticles of palladium assembled on highly ordered pyrolytic graphite (HOPG) by the adsorption of palladium molecular precursors (MPs), in dichloromethane solutions, have been prepared. Self-assemblies of palladium nanostructures on HOPG were characterized by scanning electron microscopy (SEM), Auger electron spectroscopy (AES), transmission electron microscopy (TEM), and atomic force microscopy (AFM) techniques. In this work, palladium rings had a wide variety of sizes in the nanometer range, and the ring/tube structures were preserved after a reductive process in which palladium metallic nanoparticles were formed. Noncircular structures were observed at HOPG defects and atomic step sites, as well. It is proposed that the observed ring formation of the palladium molecular precursors on HOPG substrates is related to the functional groups in the MPs, van der Waals interactions between particles and between particle-substrate, as well as the wetting properties of the solvent. In the present work, we illustrate several examples of the formation and characterization of palladium complex tubes and the resulting palladium rings, via the reduction process.

Solid-state synthesis of embedded single-crystal metal oxide and phosphate nanoparticles and in situ crystallization

“…The molecular precursor route to nanostructured materials both in solution [16][17][18] or in the solid-state [19,20] is an unconventional, yet suitable, way to obtain metallic, metal-oxidic and semiconducting nanoparticles and nanostructures. Organometallic derivatives, both cyclic and polymeric phosphazenes, are emerging as useful precursors of metallic nanostructured materials.…”

Nanospiral Formation by Droplet Drying: One Molecule at a Time

“…Nanorings have been generated by lithography (microcontact printing [18], electron beam [19], and AFM tips [20]), template-based synthesis (using droplets [21], viruses [22], and DNA [23]), self-assembly [24-27], selective dewetting on patterned surfaces [28-30], and evaporation-driven dewetting [27,31-33]. There have been fewer reports on nanospirals [34-37].…”

PdCo Nanoparticles Formation at HOPG and High Surface Area Carbon Support Vulcan XC-72R

“…The SEM image for the deposition of 0.5 mM CoPd 2 precursor solution on HOPG surface at 70 %RH shows circular structures with different diameter sizes (Figure 2A). The interaction between precursor-solvent-substrate and the evaporation process play an important role in the rings structure self-formation [8,9]. On the other hand, Figure 4B shows the modified HOPG surface with 0.4 mM CoPd 2 precursor at 80 %RH.…”

“…It has the entire surface covered with circles of sizes seemed and completely covered surface. In other similar works, results were observed using palladium and palladium-copper precursor but the control of the structures was not studied [8,11,12]. The interaction between precursor-solvent-substrate and the evaporation process play an important role in the rings structure self-formation [8,9].…”