Photocatalytic properties of flower-like BiOBr/BiOCl heterojunctions in-situ constructed by a reactable ionic liquid

In this study, flower-like BiOBr/BiOCl heterojunction photocatalyst was successfully in-situ constructed by adding a reactable ionic liquid 1-methoxyethyl-3-methylimidazolium bromide ([MOEMIm]Br) into the hydrothermal system. The samples were carefully characterized by specific surface area (BET), X-ray diffraction (XRD), scanning electron microscope (SEM), high resolution transmission electron microscope (HRTEM), energydispersive spectroscopy (EDS), surface photovoltage spectroscopy (SPS), UV-Vis diffuse reflectance spectroscopy (DRS). Electron spin resonance spectroscopy (ESR) and trapping experiments were carried out to identify active free radicals in the reaction system. Using rhodamine B (RhB) as model pollutant, the photocatalytic performance was investigated. The results show that the photoactivity of BiOBr/BiOCl heterojunctions is 5.9 times of that of the bare BiOCl. The boosted photoactivity of BiOBr/BiOCl heterojunctions can be allocated to the relative high separation efficiency of photogenerated carriers owing to the formation of heterojunctions.

Automated summary

A flower-like BiOBr/BiOCl heterojunction photocatalyst was successfully constructed in-situ by adding a reactable ionic liquid into the hydrothermal system. The improved photocatalytic performance of the heterojunction can be attributed to the high separation efficiency of photogenerated carriers.