Supported monometallic gold and bimetallic gold-silver nanoparticles on different substrates are prepared by reactive deposition of Au(acac)Me-2 and Ag(cod)(hfac) from supercritical carbon dioxide. Among others such supported metallic nanoparticles are suitable as catalysts for chemical reactions, e.g. CO oxidation. The influence of the substrate properties on the resulting mean particle size, distribution, particle structure and metal loading with focus on the provided surface area was investigated. The obtained mono- and bimetallic nanoparticles were characterized by transmission electron microscopy, electron dispersive X-ray spectroscopy, optical emission spectrometry with inductively coupled plasma and UV-Vis spectroscopy. The mean particle size varied between 2 and 26 nm for monometallic gold and between 4 and 28 nm for bimetallic gold-silver nanoparticles depending on the used substrate (mean particle size on BP2000

Keywords:Carbon dioxide;Supercritical fluid reactive deposition;Supported gold-silver nanoparticle;Intermetallic phase;Binary alloys