A novel phosphomolybdate photocatalyst K2Bi(PO4)(MoO4) has been successfully developed via a solid-state reaction. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), diffuse reflectance spectrum (DRS) and photoluminescence (PL) spectra. The photocatalytic activities of the samples prepared at different temperature were determined by the photooxidative decomposition of methylene blue (MB) in aqueous solution. The results revealed that K2Bi(PO4)(MoO4) can be used as an effective photocatalyst under UV-vis irradiation and the nanocubes obtained at 600 degrees C exhibits the highest photocatalytic activity. The photodegradation of MB by K2Bi(PO4)(MoO4) nanocrystals followed the first-order kinetics. Theoretical calculations on electronic structure confirmed the indirect optical transitions property in the absorption edge region of K2Bi(PO4)(MoO4), and the orbital constitutions of CB and VB were also analyzed. (C) 2014 Elsevier Ltd. All rights reserved.