Catalytic synthesis and characterization of spindle-type α-Fe2O3 particles

Catalytic synthesis of spindle-type hematite particles was studied for the first time under the conditions of boiling reflux and pH values ranging from 4 to 7, using Fe-2(SO4)(3) and NaOH as raw material, a trace amount of FeSO4 as the catalyst, and NaH2PO4 as the growth-regulating agent. The final products were characterized by x-ray diffraction, high-resolution electron microscopy, scanning electron microscopy, and Fourier transform infrared techniques. Primarily, the catalytic effect of ferrous ion on the conversion of ferric hydroxide was investigated. It was found that the addition of a trace amount of ferrous ion promoted fast conversion of ferric hydroxide and remarkably accelerated the transformation process to hematite. The reaction conditions affecting the conversion rate and morphologies in the presence of trace amount of ferrous ion were investigated. The final particles prepared had the characteristics of controlled size, a narrow particle size distribution, and good reproducibility.