Influence of the pH Values of the Sol–Gel State on the Properties of SnO₂ Powders Obtained From a Sol–Gel Route

Abstract

The evolution of the specific surface area and crystallite size of SnO₂ powders, prepared from a sol-gel process, was studied as a function of the calcination temperature of the stannic hydroxyde colloid, and for two different pH values (7.5 and 12.5) of the colloïdal state. The samples were characterized by TGA, IR spectroscopy, BET, and XRD techniques. The crystallite size and specific surface area were strongly affected not only by the calcination temperature, but unexpectedly, by the initial pH value of the colloïdal state. A framework model, relating the pH dependence to the resulting properties, is presented.