SPINEL FERRITES AS CATALYSTS - A STUDY ON CATALYTIC EFFECT OF COPRECIPITATED FERRITES ON HYDROGEN-PEROXIDE DECOMPOSITION

Some ferrospinels act as catalysts for the decomposition of H2O2, their effectiveness is dependent on the composition of the catalyst. This study is to find the most effective catalyst of stoichiometry M(II)Fe2(III)O4. A set of ferrites of different composition M(II)Fe2(III)O4 (M(II) = Mn, Co, Ni, Cu, Zn, Cd) was synthesized by co-precipitation and characterized by chemical analysis, X-ray diffractometry, and B.E.T. technique. A comparative assessment of the catalytic power of these ferrites from investigations of their influence on the kinetics of H2O2 decomposition in a neutral medium was made. An analysis of the data on specific rate, and the Eyrings activation parameters for the reaction sharply reveal the following: (a) The catalytic power follows the order MnFe2O4 > CoFe2O4 > CuFe2O4 > NiFe2O4 > CdFe2O4 > ZnFe2O4, MnFe2O4 is much more highly effective than the others (50-100 fold). (b) A compensation effect has been noted from the observed linearity with slightly less than unity slope between T-DELTA not-equal S0 and DELTA not-equal H0 over the entire series.