Nickel aluminum layered double hydroxide nanosheets grown on oxygen vacancy-rich TiO2 nanobelts for enhanced photodegradation of an antibiotic

Abstract Nickel aluminum layered double hydroxide nanosheets were grown on oxygen vacancy-rich TiO2 nanobelts to form heterostructured TiO2/NiAl-LDH photocatalysts. The as-prepared samples were characterized systematically by various techniques. The visible-light response of NiAl-LDH and oxygen-vacancy rich TiO2 created a direct Z-scheme heterojunction, thus contributing to the excellent photoactivity of the composite photocatalysts. Specifically, the close contact between NiAl-LDH and TiO2 at the interface promoted the directional transport of charge carriers. Tetracycline hydrochloride was selected as the target pollutant to examine the catalytic activity of samples under visible light irradiation. The results indicated that the optimal sample 2TiO2-4/NiAl-LDH exhibited excellent activity in the degradation of tetracycline hydrochloride (TC-H), and it’s degradation rate was 5 and 2.5 times than that of NiAl-LDH and TiO2-4, respectively. Moreover, the active species h+, •O2-, and •OH played significant roles in the process. According to the experimental results, the visible-light driven degradation mechanism of TC-H over 2TiO2-4/NiAl-LDH was elucidated.