Display omitted •V-doped TiO2/diatomite composite photocatalyst was synthesized.•The physiochemical property and solar light photoactivity were characterized.•The presence and influence of V ions in TiO2 matrix was systematically analyzed.•The photocatalysis for Rhodamine B were studied under solar light illumination. V-doped TiO2/diatomite composite photocatalysts with different vanadium concentrations were synthesized by a modified sol–gel method. The diatomite was responsible for the well dispersion of TiO2 nanoparticles on the matrix and consequently inhibited the agglomeration. V-TiO2/diatomite hybrids showed red shift in TiO2 absorption edge with enhanced absorption intensity. Most importantly, the dopant energy levels were formed in the TiO2 bandgap due to V4+ ions substituted to Ti4+ sites. The 0.5% V-TiO2/diatomite photocatalyst displayed narrower bandgap (2.95eV) compared to undoped sample (3.13eV) and other doped samples (3.05eV) with higher doping concentration. The photocatalytic activities of V doped TiO2/diatomite samples for the degradation of Rhodamine B under stimulated solar light illumination were significantly improved compared with the undoped sample. In our case, V4+ ions incorporated in TiO2 lattice were responsible for increased visible-light absorption and electron transfer to oxygen molecules adsorbed on the surface of TiO2 to produce superoxide radicals O2–, while V5+ species presented on the surface of TiO2 particles in the form of V2O5 contributed to e––h+ separation. In addition, due to the combination of diatomite as support, this hybrid photocatalyst could be separated from solution quickly by natural settlement and exhibited good reusability.