Influence of reduction mechanism on the morphology of cobalt nanoparticles in a silica-gel matrix

Abstract

Cobalt-chloride- and dextrose-containing silica gels were reduced in situ under nitrogen atmosphere in the temperature range of 600 to 950 °C. Analysis of kinetic data on the in situ reduction shows that, in the temperature range of 600 to 750 °C, the contracting geometry type and, in the temperature range of 800 to 950 °C, the nucleation and growth type of mechanisms remain operative. The shape and size of the reduced cobalt nanoparticles in the silica matrix was studied by examining the transmission electron micrographs of the reduced Co/SiO2 samples. The morphology of the reduced metallic particles was found to be influenced by the change in reduction mechanism.