IN-SITU REDUCTION KINETICS OF NICL2 IN SIO2 GEL MATRIX

Silica gels containing NiCl2 and dextrose have been reduced by heat-tr eating the gels under N-2 atmosphere at 800 degrees C, 850 degrees C, 900 degrees C, and 950 degrees C, respectively, The influence of the v olume ratio of ethyl alcohol to tetraethylorthosilicate and the amount of dextrose on the in situ reduction kinetics of NiCl2 in gel matrix have been investigated, The kinetic data on in situ reduction have bee n analyzed by a reduced time method which indicates that mixed mechani sms are operative, The predominant mechanism of reduction of NiCl2 in SiO2 gel matrix is of nucleation and growth type. The activation energ ies over different temperatures and fraction converted have been compu ted by the integration method.