The photocatalyst B and N codoped TiO2 (B-N-TiO2) was prepared via the sol-gel method by using boric acid and ammonia as B and N precursors. The doping mode, band structure and photocatalytic mechanism of B-N-TiO2 were investigated well and elucidated in detail. B-N-TiO2 showed the narrowed band gap and thus extended the optical absorption due to interstitial N and [NOB] species in the TiO2 crystal lattice. The coexistence of interstitial N and [NOB] species in the TiO2 crystal lattice and surface NOx species allowed the more efficient utilization of visible light. Simultaneously, interstitial [NOB] and N species and surface B2O3 and NOx species facilitated the separation of photo generated electrons and holes and suppress their recombination effectively. Hence, B-N-TiO2 showed a higher photocatalytic activity than pure TiO2, N-doped TiO2 (N-TiO2) and B-doped TiO2 (B-TiO2) under both UV and visible light irradiation. Crown Copyright (C) 2011 Published by Elsevier B. V. All rights reserved.