Enhanced photocatalytic activity of nitrogen doped TiO2 photocatalysts sensitized by metallo Co, Ni-porphyrins

Nitrogen doped anatase TiO2 powders (N-TiO2) were sensitized by four kinds of metalloporphyrins (CoTHPP, CoTPP, NiTHPP, and NiTPP). The resulting materials were characterized by XRD, TEM, XPS, DRS and N2 adsorption. The results showed that the crystal structure and morphology of N-TiO2 were not affected by the existence of porphyrin on its surface, but the surface area increased after the N-TiO2 sensitized by metalloporphyrins. The photocatalytic degradation of methyl blue (MB) experiments showed that the metalporphyrins sensitized N-TiO2 composite catalysts, especially the CoTHPP/N-TiO2 and CoTPP/N-TiO2, exhibited higher degradation efficiency than the unsentisized N-TiO2 powders. In addition, the photocatalytic degradations of MB using the composite catalysts were all demonstrated to follow first-order kinetic model. The composite catalysts can be recycled four times without significant loss of photocatalytic activity.