Semiconductor photocatalysis is a promising method to remove the harmful compounds into harmless molecules. Herein, In-doped BiOI (In-BiOI) photocatalysts with highly exposed dominant {001} facets were synthesized through a facile hydrothermal method. The XRD, SEM and TEM determinations revealed the high crystallinity structure of the samples, and the XPS results confirmed the doping of In. The InBiOI nanosheets exhibited a higher activity in the photodegradation of p-chloroaniline (PCA) than that of pristine BiOI, among which the In-2 BiOI sample (feed mole ratio of In: Bi = 2%) possessed the best performance. Doping with In didn't alter the structure, morphology, specific surface area or light absorption capacity of BiOI, but significantly improved its charge separation efficiency and transport capability, which were verified by the results of the lower PL emission, larger photocurrent intensity and smaller arc radius of EIS plots. More importantly, the mechanism of photocatalytic degradation is studied systematically, revealing that center dot O-2-and h+ were the major reactive species during the photodegradation process. Finally, the possible role of In-doping in enhancing the photocatalytic performance of BiOI is proposed. (C) 2017 Elsevier B.V. All rights reserved.