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

In this study, at first step nanopowder particles of α-Fe2O3 (Hematite) and Co3O4 were synthesized separately thorough simple chemical method from an aqueous solution of iron (III) nitrate nonahydrate (Fe(NO3)3.9H2O) and cobalt (II) nitrate hexahydrate (Co(NO3)2.6H2O) as precursors. After that, three composites from synthesized nanopowders of Fe2O3 with 8, 16 and 24 wt.% of Co3O4 were prepared. Graphite nanopowder was added to one composition of samples in weight percentages of 1.17 and 2.35. 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 Co3O4 to Fe2O3 decrease the activity of photo-catalytic process while nano-graphite enhanced photo-catalytic process by upward of ~2 % with respect to the composite without graphite nanoparticles. Stoichiometric calculations showed that the amount of hydrogen produced by water by the composite of Fe2O3-16% Co3O4- 2.35% Graphite nanoparticles was 27 μmol H2/h.g under solar light irradiation.