The carbon/TiO2 nanocomposites were fabricated by a simple one-step carbonization method with different polymers as precursors. Due to the dehydration carbonation effect of polymers, carbon was formed inside and outside of the TiO2 nanoparticles. The photo-degradation study of rhodamine B was carried out under UV-vis light irradiation, and the photocatalytic activities of carbon/TiO2 nanocomposites are affected severely by the state of carbon, including dopants and coatings. The results show that the carbon on the surface plays more important role in the photocatalytic process. (C) 2014 Elsevier B.V. All rights reserved.