Facile fabrication of CuPp-TiO2 mesoporous composite: An excellent and robust heterostructure photocatalyst for 4-nitrophenol degradation

An excellent and robust mesoporous CuPp-TiO2 photocatalyst was prepared by the self-assemble of TiO2 with Copper(II) porphyrin following a solvothermal treatment. The HRTEM images of the CuPp-TiO2 revealed the CuPp combined with TiO2 are crystalline, which is heterojunction structure. The special structure improves the photocatalytic activity of the catalyst observably. As shown in a heterojunction-type photocatalytic system, the photogenerated electrons in the CB of the CuPp migrate to the CB of the TiO2 forming reduction sites, while the photogenerated holes in the VB of TiO2 move to the VB of CuPp through the heterojunction structure forming oxidation sites. As a result, the photogenerated electrons and holes are spatially isolated, which greatly inhibits their undesirable recombination. The photodegradation of 4-nitrophenol (4-NP) illustrated the prepared CuPp-TiO2 has superior photocatalytic activity and wonderful cycling performance with the photocatalytic efficiency of 86.69% even after six cycles.