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.