In situ synthesis of flexible Bi7O9I3/carbon paper with enhanced photocatalytic activity.

• A Bi 7 O 9 I 3 /carbon paper composite was fabricated using an in-situ annealing method. • Flexible Bi 7 O 9 I 3 /carbon paper possesses hierarchical structure. • Bi 7 O 9 I 3 /carbon paper exhibited improved photocatalytic performance. • Improved carrier separation and hierarchical structure are key to performance enhancement. Although Bi 7 O 9 I 3 is an oxygen-rich bismuth oxyiodide with higher photocatalytic activity than BiOI, its applicability for photocatalytic oxidation is limited by the rapid recombination of photogenerated carriers and poor reusability. Depositing Bi 7 O 9 I 3 on flexible macro-sized carbonaceous materials is a promising approach for promoting photogenerated electron migration and improving reusability. In this study, a composite consisting of Bi 7 O 9 I 3 supported on graphitic carbon paper (Bi 7 O 9 I 3 -CP) was synthesized via the in situ transformation of a BiOI-deposited carbon paper precursor (BiOI-CP). The as-prepared Bi 7 O 9 I 3 -CP exhibited higher visible-light-driven photocatalytic activity than both Bi 7 O 9 I 3 and BiOI-CP precursor for phenol removal. The improved photocatalytic activity of Bi 7 O 9 I 3 -CP was attributed to its hierarchical structure and promoted carrier separation, as revealed by photoluminescence, pore structure, and reactive radical analyses. Moreover, owing to its macroscale size and flexibility, the Bi 7 O 9 I 3 -CP composite could be easily operated and reused, which are favorable for practical applications. [ABSTRACT FROM AUTHOR]