COPPER-RUBY MONOLITHS BY THE SOL-GEL PROCESS

Preparation and properties of uniformly dispersed Cu metal nanocluster s embedded in bulk silica an described. Clear gels were prepared from Cu(NO3)(2), H2N(CH2)(2)NH(CH2)(3)Si(OCH3)(3) (DAMO), and acid hydrolyz ed Si(OC2H5)(4) (TEOS). The role of DAMO to immobilize Cu2+ in silica network is studied. The appearance of a strong surface plasmon band of Cu colloids at 562 nm was observed after heat treatment of the gels a t 900 degrees C in 5%H-2-95%N-2 gas atmosphere. At this stage very uni form ruby-red color of the sample was established due to the formation of copper nanocrystals of mean diameter 15 nm, as confirmed by X-ray diffraction (XRD) and transmission electron microscopy (TEM).