A simple synthetic approach based on solvothermal technique and hydrogenation was developed for preparation of TiO2 nanocrystals with different morphologies such as elongated rhombic, dog-bone, oval and core-shell structured oval. The effect of oleic acid (OA) and oleylamine (OM) as two capping surfactants on the growth of TiO2 nanocrystals was investigated. The physicochemical properties of the obtained samples were characterized by various techniques including TEM, XRD, UV-vis absorption, Raman, XPS, BET, PL and photocurrent measurement. In photodegradation of RhB under simulated solar irradiation, the oval-shaped TiO2 nanocrystals with core-shell structure (co-TiO2) was superior to other TiO2 nanocrystals in catalytic activity. Moreover, the co-TiO2 nanocrystals exhibited well recyclability during multiple photocatalytic tests. These excellent properties of co-TiO2 were attributed to its special structure, including lattice-disordered surface layer and well-crystallized lattice core, and narrow band gap (2.67 eV). (C) 2017 Elsevier Ltd. All rights reserved.