Photoactive TiO2 Nanotubes and SILAR-Synthesized PbS/TiO2 Heterojunctions for Tetracycline Antibiotic Photodegradation

Titanium dioxide nanotubes (TiO2 NTs) decorated with lead sulfide nanoparticles (PbS NPs) were synthesized using the Successive Ionic Layer Adsorption and Reaction (SILAR) method at different number (n) of cycles (where n = 3, 5, and 8) and evaluated for tetracycline (TC) photodegradation under UV light. PbS NPs/TiO2 NTs heterojunctions prepared with 5 SILAR cycles showed optimal photocatalytic activity. Also, under optimized conditions, pure TiO2 NTs achieved complete TC photodegradation (99%) within 5 h under UV irradiation, with a proposed degradation mechanism based on holes (h+) and hydroxyl radicals (•OH) as dominant reactive species.