Pyropheophorbide-a/(001) TiO Nanocomposites with Enhanced Charge Separation and O Adsorption for High-Efficiency Visible-Light Degradation of Ametryn.

It is highly desired to enhance charge separation and O adsorption of the pyropheophorbide-a (Ppa) to promote visible-light activity and stability. Herein, Ppa modified 001-facet-exposed TiO nanosheets (Ppa/001T) nanocomposites with different weight ratios were fabricated via the self-assembly approach by OH induced. Compared with the bare Ppa, the 8% amount optimized 8Ppa/001T sample displayed 41-fold enhanced activity for degradation of Ametryn (AME) under visible-light irradiation. The promoted photoactivities could be attributed to the accelerated charge carrier's separation by coupling TiO as thermodynamic platform for accepting the photoelectrons with high energy from Ppa and the promoted O adsorption because of the residual fluoride on TiO. As for this, a distinctive two radicals (•O and •OH) involved pathway of AME degradation is carried out, which is different from the radical pathway dominated by •O for the bare Ppa. This work is of utmost importance since it gives us detailed information regarding the charge carrier's separation and the impact of the radical pathway that will pave a new approach toward the design of high activity visible-light driven photocatalysts.