title: Synthesis of colloidal dispersions of rhodium nanoparticles under high temperatures and high pressures.
abstract: Colloidal dispersions of rhodium (Rh) nanoparticles have been synthesized by the reduction of Rh ions (III) in high-temperature and high-pressure water, ethanol, or water-ethanol mixture under the existence of the protective polymer of poly(N-vinyl-2-pyrrolidone). The possibility of the regulation of the particle size and size distribution has been tested under several solvents at various temperatures and pressures. At 473 K and 25 MPa, particularly, concentrated colloidal dispersions of Rh particles of 2.5+/-0.5 nm were synthesized from the ionic solution of ethanol ([Rh]=15 mM) within a few seconds. Dilute colloidal dispersions of Rh particles were also synthesized from the dilute ionic solution ([Rh]=1.5 mM) with a diameter of 2.0+/-0.4 nm. From the water solution, Rh particles tended to form aggregates, especially for the lower concentration solution. In the case of solutions in water and ethanol mixture, the average diameter of Rh particles tended to be larger than in ethanol solution, and their distribution became broad.
authors: Department of Textile and Apparel Science, Faculty of Human Life and Environment, Nara Women's University, Nara 630-8506, Japan. harada@cc.nara-wu.ac.jp
authors: Masafumi
authors: M
authors: Harada
authors: Daisuke
authors: D
authors: Abe
authors: Yoshifumi
authors: Y
authors: Kimura
mesh_terms: D003102:Colloids / Q000138:chemical synthesis* / Q000737:chemistry; D000431:Ethanol / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D010316:Particle Size; D010984:Platinum / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011312:Pressure; D011760:Pyrrolidinones / Q000737:chemistry; D012238:Rhodium / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013052:Spectrometry, X-Ray Emission; D013056:Spectrophotometry, Ultraviolet; D013499:Surface Properties; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D003102:Colloids; D011108:Polymers; D011760:Pyrrolidinones; D014867:Water; D000431:Ethanol; D010984:Platinum; C042670:N-vinyl-2-pyrrolidinone; D012238:Rhodium