Nano cocatalyst-catalytic system for boosting photothermal-photocatalytic water treatment enabled by visible LEDs

Cocatalyst-catalytic system is rationally proposed in photothermal-photocatalytic water treatment. As the cocatalyst, multifunctional MoS2 enhances the photothermal effect, pre-adsorption of pollutants, and electrochemical stimulation, while defect-rich flower-like BiOBr (FBBov) is promoted to degrade tetracycline antibiotics. Consequently, the cocatalyst-catalytic FBBov@MoS2 (1 : 1) system achieves a rapid photothermal response and a remarkable catalytic activity under 5 W low-energy LED excitation. The tetracycline removal rate gets 72.3% via 45 min adsorption, reaching 95.9% after 90 min LED stimulation. For treating complicated river water, FBBov@MoS2 (1 : 1) still displays excellent performance. Significantly, the application guidance of FBBov@MoS2 (1 : 1) is proposed with statistical strategies and a generalized equation is developed to quantitatively evaluate the photothermal effect. Based on in situ thermal infrared imaging, electrochemical analysis, and ESR tests, the cocatalyst MoS2 boosts the photothermal effect to accelerate photocatalysis and promotes the spatial separation of photogenerated carriers for an enhanced production of reactive oxygen species. This discovery provides a new strategy for a low-cost and energy-saving photocatalytic method to purify water.

Automated summary

In this study, a cocatalyst-catalytic system consisting of MoS2 and BiOBr was proposed for photothermal-photocatalytic water treatment. The MoS2 cocatalyst enhanced the photothermal effect and electrochemical stimulation, while the defect-rich BiOBr promoted the degradation of tetracycline antibiotics. The cocatalyst-catalytic system showed rapid photothermal response and significant catalytic activity under low-energy LED excitation, achieving high removal rates of tetracycline in both simple and complex water samples.