The synthesis, characterization and application of Ag-SiO2-Al2O3 sol-gel composites

A new type of tertiary Ag-SiO-Al2O3 sol-gel composite with various silver c oncentrations has been prepared and characterized using combined spectrosco pic techniques of XRD, XPS, TPR, UV-VIS. DRS and SEM. It was found that the homogeneous Ag-SiO2-Al2O3 glass composites with transparent appearance cou ld be obtained when the silver content is controlled below 20 wt.%. The sil ver ion species are found to be highly dispersed in the framework of the gl ass composites and exhibited a unique thermal stability in air. In addition . the use of the Ag-SiO2-Al2O3 sol-gel composite material as promising silv er catalysts for the catalytic oxidation of methanol to formaldehyde was de monstrated. (C) 2001 Elsevier Science B.V. All rights reserved.