Construction of novel Z-scheme Ag/FeTiO3/Ag/BiFeO3 photocatalyst with enhanced visible-light-driven photocatalytic performance for degradation of norfloxacin

A novel Z-scheme Ag/FeTiO3/Ag/BiFeO3 with excellent visible-light-driven photocatalytic performance was constructed using sol-gel method followed by a photo-reduction process, and applied in the photocatalytic degradation of norfloxacin (NFX) in solution under visible light irradiation. The photocatalytic activities of Ag/FeTiO3/Ag/BiFeO3 and FeTiO3/BiFeO3 nanocomposites were compared. The effects of wt.% content of Ag, the mass ratio (FeTiO3:BiFeO3), and light irradiation time on the photocatalytic activities were assessed. The mechanism on Z-scheme Ag/FeTiO3/Ag/BiFeO3 photocatalytic degradation was also proposed. The results show that Ag/FeTiO3/Ag/BiFeO3 has higher photocatalytic activity than FeTiO3/BiFeO3, and the loading of Ag improves the photocatalytic activity of catalysts. The photocatalytic degradation extent reaches 96.5% within 150 min, when using Ag/FeTiO3/Ag/BiFeO3 at 2.0 wt% Ag (FeTiO3:BiFeO3 = 1.0:0.5). In addition, Ag/FeTiO3/Ag/BiFeO3 can be reused with excellent photocatalytic stability. The study reveals that the active species such as hydroxyl radicals (OH), holes (h+) and superoxide radicals (O2−) are generated during the photocatalytic process using Ag/FeTiO3/Ag/BiFeO3. These results on the enhanced photocatalytic activity are attributed to the synergistic photocatalytic effects of FeTiO3 and BiFeO3 with narrow band gaps mediated by Ag. Hence, the Z-scheme Ag/FeTiO3/Ag/BiFeO3 photocatalytic system demonstrates great promise in treating antibiotics in water and wastewater using solar energy.