Strengthened photocatalytic removal of bisphenol A under visible light by magnetic ternary heterojunctions Bi4O5Br2/Bi4O5I2/Fe3O4

Abstract

Magnetic ternary composites Bi 4 O 5 Br 2 /Bi 4 O 5 I 2 /Fe 3 O 4 (BBF) were constructed by the combination of exotic Fe 3 O 4 nanoparticles and Bi 4 O 5 Br 2 /Bi 4 O 5 I 2 with controllable molar ratios of Br to I through a facile one-pot route. Microstructural, morphological, and optical features of achieved composites were thoroughly characterized by a succession of analytical techniques. It was realized that three expected components were coexisted to form efficient heterojunction structures. These magnetic composites showed reinforced photocatalytic removal of bisphenol A (BPA) under visible light illumination. Particularly, the best candidate BBF(3:7) possessed the largest apparent reaction rate constant of 0.041 min −1 that was respectively about 1.95, 372.73, 4.71, 39.42, and 3.72 times those of Bi 4 O 5 I 2 /Fe 3 O 4 , Bi 4 O 5 Br 2 /Fe 3 O 4 , Bi 4 O 5 I 2 , Bi 4 O 5 Br 2 , and BB(3:7), mainly attributed to the strengthened visible-light absorption by the shrinkage of band gaps, the harmony of various morphologies, the suitable phase composition, and the promoted segregation of charge carriers by ternary heterojunctions with proper band structures. In addition, a possible photocatalysis mechanism was proposed by entrapping experiments and band structures estimation. The sufficient reusability by recycling experiments together with enhanced photocatalytic outcome ensured these magnetic composites as potential and applicable candidates in fields of environmental protection and energy reservation. • Magnetic composites Bi 4 O 5 Br 2 /Bi 4 O 5 I 2 /Fe 3 O 4 were prepared in a facile manner. • Ternary heterojunction structures were formed in these composites. • These magnetic composites showed enhanced photocatalytic removal of BPA. • A plausible photocatalysis mechanism was conjectured.