Synthesis and Characterization of Photocatalytic Activity of Hematite/ Cobalt Oxide/ Graphite Nanocomposites

In this study, at first step nanopowder particles of  α-Fe۲O۳ (Hematite) and  Co۳O۴ were synthesized separately thorough simple chemical method from an aqueous solution of iron (III) nitrate nonahydrate (Fe(NO۳)۳.۹H۲O) and cobalt (II) nitrate hexahydrate (Co(NO۳)۲.۶H۲O) as  precursors.  After that, three composites from synthesized nanopowders of Fe۲O۳ with ۸, ۱۶ and ۲۴ wt.% of Co۳O۴ were prepared. Graphite nanopowder was added to one composition of samples in weight percentages of ۱.۱۷ and ۲.۳۵. The composition and morphology of the composites were investigated by XRD and FE-SEM, respectively. FE-SEM analysis showed that the morphology of the powders and composites were all spherical in nanoscale. The photocatalytic activity of the composites was examined by measuring the photo-degradation of the aqueous solution of methylene blue under simulated solar light. To determine the photo catalytic activity, the degradation of methylene blue (MB) in the absence of light (dark test) was taken as well. Results showed that addition of Co۳O۴ to Fe۲O۳ decrease the activity of photo-catalytic process while nano-graphite enhanced photo-catalytic process by upward of ~۲ % with respect to the composite without graphite nanoparticles. Stoichiometric calculations showed that the amount of hydrogen produced by water by the composite of Fe۲O۳-۱۶% Co۳O۴- ۲.۳۵% Graphite nanoparticles was ۲۷ μmol H۲/h.g under solar light irradiation.

Keywords:

Synthesis , Photo catalyst , hydrogen , Methylene blue , Photoactivity