Coupling effect of la doping and porphyrin sensitization on photocatalytic activity of nanocrystalline 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.