Novel 3D flower-like bismuth oxyiodide (BiOI) nanomaterials were obtained via a facile solvothermal method using bismuth nitrate (Bi(NO3)3) and potassium iodide (KI) as precursors and diethylene glycol as the capping reagent. The morphology of the BiOI nanoarchitecture strongly depends on the experimental conditions such as the presence of diethylene glycol and hydrothermal time. The photocatalytic property of the BiOI nanostructures by monitoring the degradation of rhodamine B (RhB) and methyl orange (MO) mixed dyes was studied under visible light illumination, which has not been reported previously. The degradation of single cationic RhB dye is faster when compared with that of anionic MO dye. This result is due to the surface negative charges on the BiOI nanoflowers that display good selectivity towards positive RhB dye organic groups owing to electrostatic attraction.
In this work, a visible-light-driven photoelectrochemical (PEC) sensing platform was developed based on BiOI nanoflowers/TiO 2 nanotubes (BiOI NFs/TiO 2 NTs) for detection of atrazine (ATZ). The BiOI NFs/TiO 2 NTs p–n heterojunctions synthesized by decorating BiOI NFs on TiO 2 NTs via simple hydrothermal approach exhibit strong visible-light absorption ability, high photocurrent response and PEC activity. Thus BiOI NFs/TiO 2 NTs heterostructures were first explored to act as the photoelectrode for the immobilization of the anti-ATZ aptamer to develop a PEC sensing platform. The design PEC aptasensing platform exhibits prominent analytical performance for determination of ATZ with a low detection limit of 0.5 pM under visible-light irradiation, and displays good selectivity for ATZ in the control experiments. The superior behavior of the sensing platform could be ascribed to the design of the appropriate sensing material with tubular microstructure, excellent PEC response of the photoelectrode, and the large loading amount of aptamer. Meanwhile, the PEC sensing platform was used to determine ATZ in environmental samples and a satisfied result was obtained.