Coherent Bi2O3-TiO2 hetero-junction material through oriented growth as an efficient photo-catalyst for methyl orange degradation

In this work, we report the synthesis of a Bi2O3-TiO2 hetero-junction (HJ) material through a facile colloidal method. The hetero-junction formation follows a growth with a 145°Bi2O3/TiO2 crystal angle, owing to the large lattice mismatch between Bi2O3 and TiO2 crystals. With the Bi2O3-TiO2 hetero-junction material as a photocatalyst, methyl orange is degraded completely within two hours under common UV-lamp irradiation. The photo-catalyst remains highly-active for complete photo-degradation of methyl orange even after multiple experiments. The remarkable photo-catalytic properties are attributed to the remarkable mono-dispersivity of the colloidal Bi2O3-TiO2 nano-structure as well as the refined band structure with a valence band of 0.85 eV below that of TiO2 crystal.