Construction of 2D/3D black g-C3N4/BiOI S-scheme heterojunction for boosted photothermal-assisted photocatalytic tetracycline degradation in seawater

Utilization of semiconductor photocatalyst to degrade broad-spectrum antibiotics (tetracycline, TC) in seawater to solve environmental pollution and human health problems has become a research hotspot in recent years. In this work, 2D/3D black g-C3N4/BiOI S-scheme heterojunction was constructed by loading 2D black g-C3N4 (CN-B) nanosheets onto 3D spherical bismuth oxyiodide (BiOI) surface by solvothermal method to improve TC degradation efficiency. The TC (30 mg/L) photodegradation efficiency of the optimal 10% CN-B/BiOI sample was up to 93% after 60 min visible light irradiation, which was significantly higher than that of pure CN-B and BiOI. Remarkably, the 2D/3D heterojunction formed between CN-B and BiOI can not only effectively improve the light absorption and separation efficiency of carriers, but also the photothermal effect of CN-B increases the reaction temperature, thereby promoting the photothermal-assisted photocatalytic degradation activity. This work provides a promising strategy and systematic method for the design of photocatalytic system for photothermal-assisted degradation antibiotic contaminants in seawater.