CJ11Aand CeTiSiO-CJ11B, respectively) were the first successful examples of Ce 4þ and Ce 4þ /Ti 4þ mixed silicates synthesized under mild hydrothermal conditions at 503 K. Their isostructure is confirmed by the powder X-ray diffraction (XRD) analysis. The single-crystal XRD analysis of CeSiO-CJ11A reveals that its structure is comprised of [Si 6 O 18 ] n 12nÀ cyclosilicate anions that are linked via CeO 6 octahedra, giving rise to a three-dimensional (3D) framework that contains 6-membered ring channels delimited by the SiO 4 tetrahedra and CeO 6 octahedra along the [101]-direction. Charge neutrality is achieved by Na þ ions located in the channels. Interestingly, the surface photovoltage (SPV) and transient photovoltage (TPV) studies of CeSiTiO-CJ11B show that it exhibits n-type semiconductor characteristics and a slow recombination process.