Synthesis of AgBr/Ti 3 C 2 @TiO 2 ternary composite for photocatalytic dehydrogenation of 1,4-dihydropyridine and photocatalytic degradation of tetracycline hydrochloride.

In this work, AgBr/Ti 3 C 2 @TiO 2 ternary composite photocatalyst was prepared by a solvothermal and precipitation method with the aims of introducing Ti 3 C 2 as a cocatalyst and TiO 2 as a compositing semiconductor. The crystal structure, morphology, elemental state, functional groups and photoelectrochemical properties were studied by XRD, SEM, TEM, XPS, FI-IR and EIS. The photocatalytic performances of the composites were investigated by the photodehydrogenation of diethyl 1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylate (1,4-DHP) and the photodegradation of tetracycline hydrochloride (TCH) under visible light irradiation ( λ > 400 nm). The AgBr/Ti 3 C 2 @TiO 2 composite photocatalyst showed enhanced photocatalytic performance in both photocatalytic reactions. The photocatalytic activity of the composite photocatalyst is dependent on the proportional content of Ti 3 C 2 @TiO 2 . With optimized Ti 3 C 2 @TiO 2 proportion, the photocatalytic ability of the AgBr/Ti 3 C 2 @TiO 2 composite was 24.5 times as high as that of Ti 3 C 2 @TiO 2 for photodehydrogenation of 1,4-DHP and 1.9 times as high as that of pure AgBr for photodegradation of TCH. The enhanced photocatalytic performance of the AgBr/Ti 3 C 2 @TiO 2 composite should be due to the formation of a p-n heterojunction structure between AgBr and Ti 3 C 2 @TiO 2 and the excellent electronic properties of Ti 3 C 2 , which enhanced the visible light absorption capacity, lowered the internal resistance, speeded up the charge transfer and reduced the recombination efficiency of photo-generated carriers. Mechanism studies showed that superoxide free radical (˙O 2 - ) was the main active species. In addition, the composite photocatalyst also displayed good stability, indicating its reutilization in practical application.