NATURE OF PHOTOCATALYSIS IN BiFeO3 SUSPENSIONS – HETEROGENEOUS, HOMOGENEOUS OR DYE-SENSITIZED?

Abstract

Bismuth ferrite (BiFeO3) powders were synthesized by auto-combustion method. To decrease the quantity of active phase and improve the specific surface area, composites of BiFeO3 and natural porose materials (diatomaceous earth and cuttlebone) were prepared by chemical method from solution and calcined at low temperature. Such obtained powders were used as adsorbents and photocatalysts in methylene blue water solutions. Nature of photocatalysis under visible and UV-Vis light was examined under different pH conditions and presence of hydrogen peroxide, dissolved iron(III), oxalates and some other ions. Methylene blue is capable to absorb sunlight and insert electrons into semiconductor, so possibility of this way achieved dye-sensitization was studied [1]. Composites expressed better properties than individual components confirming the synergetic effect [2]. Acidic conditions were more suitable for decolorization, so possible Fenton reaction based homogeneous catalysis was also considered.