Novel Co–Fe–O micro/nano structures manipulated by urea and their applications in degradation of hexachlorobenzene

AbstractFour microsized composite materials containing oxides of cobalt and iron were prepared via a polyol-mediated process involving aggregation of nanoparticles that formed initially. Two alkoxide precursors with different morphologies were obtained by controlling the amount of urea during the synthesis stage and calcinate each precursor in nitrogen and air afford four products. Hexagonal flower-like particles were formed in the absence of urea, while tetragonal brick-like structures were obtained in the presence of urea. The morphologies were retained during calcination. However, the compositions of the materials depend on the presence of air or nitrogen during calcination. In the absence of urea during initial synthesis, CoFe2O4 was formed when calcined in air, but a mixture of Fe3O4, Fe2O3, CoO and a small amount of Co3O4 was obtained when calcined in nitrogen. In the presence of urea, CoFe2O4/Fe2O3 was formed when calcined in air and a mixture, Co0.62Fe2.38O4/Fe3O4, was formed when calcined in nitr...