Sol-Gel ceramic glazes with photocatalytic activity.

A frit is a glassy ceramic composition that has been fused, quenched, and granulated. A single frit or a mixture of frits and ceramic materials forms a ceramic glaze. The purpose of this pre-fusion is to render any soluble and/or toxic components insoluble by rendering it inert in a glassy composition with silica and other added oxides. The ceramic glaze dispersed in water (ceramic slip) is deposited on a ceramic body and fired for waterproofing and aesthetic purposes. Multicomponent frits (zinc-potassium borosilicate system) with similar behavior to conventional ceramic frits for single-firing ceramic glazes ("monoporosa" glazes fired at 1080 °C) were prepared by Sol-Gel methods (monophasic and polyphasic gels) avoiding the pre-fusion and characterized as photocatalytic agents (showing high degradation activity on Orange II). The effect of doping with bandgap modifiers (VO, SbO and SnO) and also with devitrification agents (ZrO to crystallize zircon, AlO to anorthite, MoO to powellite and ZnO to gahnite ZnAlO) were analyzed. Multicomponent frits (zinc-potassium borosilicate system) with similar behavior to conventional ceramic frits for single-firing glazes (1080 °C) prepared by Sol-Gel methods (monophasic and polyphasic gels), without pre-fusion, shows photocatalytic activity.