Porous Bi5O7I nanosheets were successfully prepared by a facile thermal decomposition of BiOI nanosheets in air at 500 degrees C for 2 h. The crystal structure, surface morphology, specific surface area, and optical properties of resulted materials were characterized by XRD, SEM, TEM, nitrogen adsorption-desorption isotherms and UV-vis diffuse reflectance spectroscopy, respectively. Moreover, the photodegradation ability of porous Bi5O7I nanosheets on target pollutant Rhodamine B (RhB) under visible light irradiation (lambda >= 400 nm) and simulated sunlight irradiation was investigated. The results indicated that porous Bi5O7I nanosheets were mainly composed of irregular nanosheets. With the layer thickness of 30-50 nm and pore diameter distribution around 25 nm, it belonged to mesoporous material. Compared with BiOI, the photocatalytic activity of porous Bi5O7I nanosheets under visible light was appropriately 2 times than that of BiOI, and 2.3 times under simulated sunlight. The major reasons for the improvement in catalytic performance were the existence of multiple pores and the special band structure. (C) 2014 Elsevier B.V. All rights reserved.