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

In this work, AgBr/TiC@TiO ternary composite photocatalyst was prepared by a solvothermal and precipitation method with the aims of introducing TiC as a cocatalyst and TiO 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 ( > 400 nm). The AgBr/TiC@TiO composite photocatalyst showed enhanced photocatalytic performance in both photocatalytic reactions. The photocatalytic activity of the composite photocatalyst is dependent on the proportional content of TiC@TiO. With optimized TiC@TiO proportion, the photocatalytic ability of the AgBr/TiC@TiO composite was 24.5 times as high as that of TiC@TiO 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/TiC@TiO composite should be due to the formation of a p-n heterojunction structure between AgBr and TiC@TiO and the excellent electronic properties of TiC, 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) was the main active species. In addition, the composite photocatalyst also displayed good stability, indicating its reutilization in practical application.