Synthesis of N and La co-doped TiO2/AC photocatalyst by microwave irradiation for the photocatalytic degradation of naphthalene

La and N co-doped TiO2 nanoparticles supported on activated carbon (TiO2/AC) were synthesized through a microwave-assisted solegel method for the synergistic removal of naphthalene solution by photocatalytic degradation. Results showed that the La and N ions were incorporated into the TiO2 framework in both the anatase and rutile phases of TiO2 for single doped and co-doped samples, which narrowed the band gap of TiO2 from 2.82 to 2.20 eV. The PL spectra of the samples showed a decrease in the recombination centers when N and La were introduced in TiO2/AC. The 0.001La-N-TiO2/AC photocatalyst exhibited the highest degradation efficiency of 93.5% for naphthalene under visible light within 120 min. This result was attributed to a synergistic effect involving the efficient inhibition of the recombination of photogenerated electrons and holes, the increase in surface hydroxyl, surface area, volume pores, and the increase of uptake in the visible light region. In addition, the high apparent rate constant indicated that La and N co-doping result in the increase of photoactivity. This study demonstrated the co-doped TiO2/AC is a highly efficient photocatalyst for the removal of naphthalene. The results provided valuable information on the mechanism of naphthalene decomposition. (C) 2016 Elsevier B.V. All rights reserved.