Structural studies of trigonal lamellar particles of gold and silver

Abstract

The results of detailed structural studies of trigonal lamellar particles of both gold and silver are presented. The particles have been characterized both in sol by means of optical spectroscopy and powder X-ray diffraction and ex sol using high resolution electron microscopy in both plan view and profile imaging modes. The results of these studies have indicated that the particles have a trigonal outline and are shortened along a ≺111≻ direction to give a plate-like morphology. The presence of small numbers of parallel {111} twin planes has also been confirmed and used to explain the presence of the formally forbidden ⅓{422} reflections observed in plan view. The precise structural requirements for the observation of such reflections has also been confirmed using multislice calculations. Possible growth mechanisms for these particles are also discussed.

Experimental and theoretical study on the synthesis of gold nanoparticles using ceftriaxone as a stabilizing reagent for and its catalysis for dopamine

“…On the nanometer scale metals (most of them are fcc) tend to nucleate and grow into twinned and multiple twinned particles with their surfaces bounded by the lowest-energy (111) facets [22]. Other morphologies with less stable facets have only been kinetically achieved by adding chemical capping reagents to the synthetic systems [23][24][25][26].…”

Preparation and Characterization of Different Shapes of Silver Nanostructures in Aqueous Solution

“…Xray diffraction (XRD) and energy dispersed X-ray (EDX) spectra [ Fig. (S1a,b), respectively] confirmed that the NFs consisted of Ag atoms [5,[44][45]. The Ag NFs exhibited strong extinction coefficients in the visible-IR region [from 400 to 1200 nm; Fig.…”

Mesoscopic Assembly and Other Properties of Metal and Semiconductor Nanocrystals

“…The successful synthesis of nanocrystals involves three steps nucleation, growth and termination by the capping agent or ligand [35][36][37]. Though the reaction temperature and reagent concentrations provide a rudimentary control of the three steps, it is often impossible to independently control them and so the obtained nanocrystals usually exhibit a distribution in size.…”

“…Though the reaction temperature and reagent concentrations provide a rudimentary control of the three steps, it is often impossible to independently control them and so the obtained nanocrystals usually exhibit a distribution in size. Typically, the distribution is log-normal with a standard deviation of 10% [37]. Given the fact that properties of the nanocrystals are size-dependent, it is significant to be able to synthesize nanocrystals of precise dimensions with minimal size-distributions.…”

“…The stabilizing agents employed include surfactants such as long chain thiols or amines or polymeric ligands such as polyvinylpyrrolidone (PVP). Reduction of metal salts dissolved in appropriate solvents produces small metal particles of varying size distributions [35][36][37][38]. A variety of reducing agents have been employed for the reduction.…”