Coupling effect of La doping and porphyrin sensitization on photocatalytic activity of nanocrystalline TiO2

• La doping and sensitization of TiO2 photocatalyst have been jointly exploited.
• La doping can decrease crystallite size and increase specific surface area of TiO2.
• Porphyrin sensitization facilitates the radical generation in photocatalysis process.
• Coupling effects of doping and sensitization improve the photoactivity of TiO2.

Metal doping and sensitization of photocatalyst have been jointly exploited as a novel strategy to improve photocatalytic activity under visible light irradiation. 5, 10, 15, 20-tetrakis (4-chlorophenyl) porphyrin-Cu (II) (CuPp) is chosen to sensitize La-doped TiO2 (La–TiO2) nanocrystalline. La doping results in smaller crystallite and larger specific surface area. La doping or sensitization of TiO2 exhibits higher absorption in visible-light region and photocatalytic degradation efficiency of methyl orange (MO) than pristine TiO2. Coupling effect of La doping and CuPp sensitization leads to the excellent photocatalytic activity under visible light irradiation. A tentative mechanism for the enhancment of photocatalytic activity under visible light irradiation is proposed.