Enhanced photocatalytic performance of Bi 4 O 5 Br 2 with three-dimensionally ordered macroporous structure for phenol removal

Herein, a series of three-dimensionally ordered macroporous (3DOM) Bi 4 O 5 Br 2 photocatalysts with different macropore sizes were successfully fabricated via a polymethyl methacrylate (PMMA) template method. The photocatalytic activity for phenol degradation over 3DOM Bi 4 O 5 Br 2 first increased and then decreased with the rise in macropore size. Specifically, 3DOM Bi 4 O 5 Br 2 -255 (macropore diameter ca. 170 nm) exhibits the best photocatalytic activity in the static system, which is about 4.5, 7.3, and 11.9 times higher than those of bulk Bi 4 O 5 Br 2 , Bi 2 WO 6 , and g-C 3 N 4 , respectively. Meanwhile, high phenol conversion (75%) is also obtained over 3DOM Bi 4 O 5 Br 2 -255 in the flow system under full spectrum irradiation. Furthermore, 3DOM Bi 4 O 5 Br 2 -255 also shows strong mineralization capacity owing to the downward shift of valance band position (0.15 V) as compared with Bi 4 O 5 Br 2 . Total organic carbon (TOC) removal rate over 3DOM Bi 4 O 5 Br 2 -255 (62%) is much higher than that of Bi 4 O 5 Br 2 (17%). The enhancement in photocatalytic performance of 3DOM Bi 4 O 5 Br 2 -255 is attributable to its better phenol adsorption, O 2 activation, and charge separation and transfer abilities. This work combines the advantages of 3D structure and surface dangling bonds, providing new possibilities for designing highly efficient photocatalysts for pollutants removal.