Pyropheophorbide-a/(001) TiO2 Nanocomposites with Enhanced Charge Separation and O2 Adsorption for High-Efficiency Visible-Light Degradation of Ametryn

It is highly desired to enhance charge separation and O2adsorption of the pyropheophorbide-a (Ppa) to promote visible-light activity and stability. Herein, Ppa modified 001-facet-exposed TiO2nanosheets (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 TiO2as thermodynamic platform for accepting the photoelectrons with high energy from Ppa and the promoted O2adsorption because of the residual fluoride on TiO2. As for this, a distinctive two radicals (•O2−and •OH) involved pathway of AME degradation is carried out, which is different from the radical pathway dominated by •O2−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.Keywords:Ppa;001-facet-exposed TiO2;charge separation;visible-light photocatalysis;Ametryn