The pH effect of the precursor solutions on the phase, morphologies, and photocatalytic activity of Bi2MoO6synthesized by a hydrothermal reaction at 180°C for 20 h was investigated. X-ray powder diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) spectrometry, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) revealed the presence of pure orthorhombic well-crystallizedγ-Bi2MoO6nanoplates, including the symmetric (A1g) and asymmetric (A2u) stretching vibrations of the MoO6octahedrons involving the motion of apical oxygen atoms. The photocatalytic activity of Bi2MoO6nanoplates at the pH 6 determined via the decomposition of rhodamine-B (RhB) organic dye was the highest at 98.66% decolorization under Xe light irradiation.