Preparation, characterization and photocatalytic activity of ZnO, Fe2O3 and ZnFe2O4

ZnO, Fe2O3 and ZnFe2O4 were synthesized by precipitation or coprecipitation at constant pH. After aging, washing and drying, the solids were calcined at 800 degreesC. The samples were characterized by XRD, TGA, N-2 physisorption, UV-Vis and TPR. The photocatalytic degradation of phenol was studied in a batch reactor and TiO2 (Degussa, P-25) was used as a reference catalyst. Pure ZnO and Fe2O3 were obtained at 800 degreesC, whereas ZnFe2O4 and alpha-Fe2O3 (segregated) were detected in the zinc ferrite sample. TPR experiments showed the reduction peaks in the range of 350-800 degreesC only with Fe2O3 and ZnFe2O4, attributed to Fe3+ to Fe2+ reduction and complete dehydroxylation, The photodegradation of phenol (samples calcined at 800 Q showed small but significant variations that decreased in the order: TiO2 > ZnFe2O4 > ZnO > Fe2O3, Subproducts such as hydroquinone, catechol and benzoquinone were mainly detected. In particular, attention was focused on our prepared materials because after 24 It they did not dissolve as happened with TiO2. (C) 2002 Elsevier Science B.V. All rights reserved.