Enhancing visible light photocatalytic degradation performance and bactericidal activity of BiOI via ultrathin-layer structure

[Display omitted] •The preparation approach for BiOI ultrathin-layer is convenient.•The band gap of BiOI ultrathin-layer is extended compared to those of bulk BiOI.•h-BiOI displays excellent photocatalytic activity on decomposing RhB solution.•h-BiOI also exhibits improved photocatalytic bactericidal performance. Hollow flower-like BiOI photocatalyst (h-BiOI) was obtained via a facile solvothermal method, which consists of ultrathin nanosheets with a thickness of about 2nm. The structures and morphologies of as-prepared products were characterized by XRD and SEM and the absorption properties were determined by DRS. h-BiOI exhibit a more positive VB band than that of bulk BiOI (b-BiOI), which suggests a much stronger oxidation ability of the former. Therefore, h-BiOI displays completely degradation ability towards RhB under visible light irradiation while b-BiOI only decomposes RhB into segmental fragments under the same conditions. In addition, h-BiOI exhibits significantly higher antibacterial performances than b-BiOI under LED (470nm) light irradiation. Besides the higher oxidation ability, the excellent photocatalytic activity of h-BiOI may be due to the ultrathin nanosheet, which takes less time for the photogenerated electrons and holes to reach the surface and therefore reduce their recombination.