Synthesis of polymer-stabilized nanosized rhodium particles in the interlayer space of layered silicates

Rhodium nanoparticles were prepared by homogeneous nucleation in aqueous polymer solution and by heterogeneous nucleation on the interlayer space of layered montmorillonite and kaolinite minerals by reduction with NaBH4 in aquatic dispersion. Rhodium particles were stabilized by polymers and by the lamellae of layered silicates. The effect of the molecular mass and the concentration of polymers on the size of the particles formed was studied using neutral polyvinylpyrrolidone, cationic poly(diallydimethylammonium chloride), and anionic poly(sodium 4-styrenesulfonate). The effect of the concentration of the rhodium precursor was also examined; reduction of rhodium ions was controlled by X-ray photoelectron spectroscopy. Interlamellar incorporation of nanoparticles was monitored by X-ray diffraction and small-angle X-ray scattering verified by transmission electron microscopy. Average particle size fell within the range of 1-3 nm, depending on the stabilization method used and the concentration of precursor rhodium ions.