Preparation of silver nanoparticles in oxide matrices derived by the sol-gel method

Consideration is given to the processes proceeding in the Ag+-SiO2 and Ag+-GeO2 systems at ahigh silver content upon their heat treatment in air. These processes lead to the formation of silver-oxide nano-composite films. It is revealed that the formation of silver nanoparticles is due to thermally stimulated interaction between silver ions and the oxide matrix with the formation of silver silicate (germanate), which, at temperatures above 600degreesC, undergoes decomposition into silver nanoparticles and silicon (germanium) dioxide. It is demonstrated that, under the given conditions, silver particles are encapsulated into oxide particles, which prevents their further oxidation up to 900degreesC.