Photocatalytic Reduction of Hexavalent Chromium (Cr6+) Over BiOI Calcined at Different Temperature Under Visible Light Irradiation

Abstract Synthesis of photocatalysts with high charge separation and transfer efficiency are of huge significance in the photocatalytic waste water treatment technology. Herein, we report the phase transformation of bismuth oxyiodide through the facile calcination of BiOI microsphere at different temperatures. Different phases including BiOI, Bi 4 O 5 I 2 and Bi 5 O 7 I were obtained as confirmed by different characterization techniques studied. The synthesized photocatalysts depicted high visible light absorption efficiency in a range of ∼ 655 to 420 nm. The photocatalytic activity of the synthesized photocatalyst were studied on the reduction of the highly carcinogenic and toxic hexavalent chromium as the representative heavy metal in waste water. Bi 4 O 5 I 2 depicted high photocatalytic activity (k=0.0366 min −1 ) which was ascribed to high charge separation and transfer as evidenced in PL, photocurrent response and EIS. This study may furnish a new concept in designing a series of phases that are more advantageous in solar energy conversion.