Unique kinetics feature and excellent photocatalytic performance of tetracycline photodegradation using yolk-shell TiO2@void@TiO2:Eu3+

Abstract

The multifunctional yolk-shell TiO2 @void@TiO2:Eu3+ calcined at different temperatures were successfully fabricated by sacrificial template method for the photodegradation of tetracycline. The impacts of yolk-shell and calcination temperature on the photoluminescence and photocatalytic properties have been investigated in detail. The photoluminescence results show that sample calcined at 800 °C exhibits the strongest red emission. The photocatalytic efficiency for tetracycline reached 90.34 % in 50 min at 20 mg/L TC solution by sample calcined at 900 °C. The kinetics fitting curves is with different slopes, which is reported for the first time so far. Meanwhile, the photocatalytic mechanism and possible photodegradation pathway of tetracycline were proposed. Compared with the double-shell samples, the yolk-shell samples show a high photodegradation rate within 5 min and unique kinetics feature. The analysis of photocatalytic kinetics provides a new idea for studying the photocatalysis mechanism. The rapid tetracycline photodegradation by the yolk shell material also provides new strategies for practical water purification.