Polypyrrole decorated BiOI nanosheets: Efficient photocatalytic activity for treating diverse contaminants and the critical role of bifunctional polypyrrole.

A conducting polymer polypyrrole (Ppy) was first employed to decorate BiOI for fabricating an organic-inorganic hybridized Ppy-BiOI nanocomposite photocatalyst via a facile in situ precipitation strategy at room temperature. The composite and intimate interface was confirmed by FTIR, XPS, SEM, HRTEM and TEM-mapping. In comparison with pristine BiOI, the Ppy-BiOI hybrids present significantly enhanced photocatalytic activity for degradation of Rhodamine B (RhB) under visible light (λ>420nm). Particularly, the Ppy-BiOI composite exhibits an universal photocatalytic performance for removing diverse industrial pollutants and antibiotics, including bisphenol A, 2,4-dichlorophenol, tetracycline hydrochloride and chlortetracycline hydrochloride. The enhanced photocatalytic activity of Ppy-BiOI composite is found attributable to the bifunctional role that Ppy takes. Ppy-BiOI composite has an enhanced specific surface area, which benefits adsorption and generation of more active sites. Notably, high separation and transfer of the photogenerated charge carriers was achieved on the interface between Ppy and BiOI, and the photogenerated hole transfer action of Ppy is demonstrated. Therefore, synergistic effect of adsorption-enrichment and photocatalytic degradation is realized. Our work may offer a guideline to manipulate high-performance Bi-based composite photocatalyst by coupling conducting polymers.