Facile fabrication of plasmonic p-n heterojunction Ag@Ag₂O-PbBiO₂Br photocatalyst for levofloxacin and tetracycline degradation: Active free radicals for degraded mechanism insight

This research used a facile chemical precipitation-photoreduction technique to fabricate a plasmonic p-n heterojunction Ag@Ag2O-PbBiO2Br (A@AO-PB) photocatalysts. The resulting materials were evaluated using various characterization techniques. Levofloxacin (LEV; 100 ml, 20 mg/l) and tetracycline (TC; 100 ml, 20 mg/l) were successfully photodegraded by the optimized 10 min-A@AO-PB (50 mg) in 120 min under visible light, with efficient degradation rates of 80.6 % and 87.0 %, respectively. The increased absorption of visible light by local surface plasmon resonance (LSPR) of plasmonic Ag and the effective separation and transfer of photogenerated carriers could be the reasons for the increase in efficiency of A@AO-PB. Transient photocurrent response (TRP), electrochemical impedance spectroscopy (EIS), and photoluminescence (PL) studies have all confirmed that 10 min-A@AO-PB effectively separates and transfers photogenerated carriers. In addition, scavenger studies have shown that the dominant active species that participated in the removal of LEV and TC are h(+) and center dot O-2(-). To find intermediates, the potential photodegradation pathways of LEV and TC were also investigated through HPLC-MS. Thus, this work describes a new photocatalyst design and a desirable plasmonic photocatalyst with p-n heterojunction that can effectively degrade LEV and TC antibiotics when exposed to visible light.