LUMINESCENCE STUDIES OF CERIUM(III) INCORPORATED IN SILICA-GELS PREPARED USING SOL-GEL METHODS

Sol-gel methods have been adapted for the incorporation of cerium(III) into a silica gel network, and the resulting gels have been prepared either with or without the use of formamide as a drying control chemic al additive (DCCA). The use of formamide and Ce(III) has been found to result in lanthanide-assisted hydrolysis of the amide, leading to cry stallization phenomena during gelation. We describe strategies to avoi d this, as well as the results of luminescence studies on the Ce/silic a gels. The latter have been used to observe the characteristic lumine scence of gel-supported cerium, and have also been employed as a probe of the gelation process. This has been found to lead to increasing lu minescence intensity, with the most significant increases occurring af ter gelation and-during the drying stage.