The wide-band-gap semiconductor (BiO)(2)CO3 was modified by interior doping with I- ions and surface loading with BiOI to prepare a highly efficient visible-light active photocatalyst for the degradation of methyl orange and phenol. The interior l(-) ions elevate the valence band position of (BiO)(2)CO3 and induce visible-light photocatalytic activity, while the in-situ-formed BiOI/I-(BiO)(2)CO3 heterojunction significantly improves the separation of photoinduced charge carriers. By the action of the reactive species h(+) and center dot O-2(-), methyl orange and phenol were degraded over the novel BiO\I/I-(BiO)(2)CO3 composite at rates that were 18- and 4-times, respectively, those of unmodified (BiO)(2)CO3. Thus, the findings presented here may be widely applied in the development of wide-band-gap semiconductor photocatalytic systems for the highly efficient removal of contaminants from wastewater. (C) 2017 Elsevier B.V. All rights reserved.