THE HIGHLY EFFICIENT BiOCl/KBiO3 p-n HETEROJUNCTION PHOTO-CATALYSTS UNDER VISIBLE LIGHT IRRADIATION

Abstract

BiOCl/KBiO3 p-n heterostructures with hierarchical mesoporous architectures were successfully synthesized via a facile in situ method. The X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) results indicate the formation of heterojunctions between BiOCl and KBiO3. The photocatalytic performance of the as-prepared samples was investigated by the degradation of dye Rhodamine B (RhB) under visible light irradiation. BiOCl/KBiO3 composite has never been used to photodegrade the RhB which is a common dye and very difficult to degrade. The results demonstrated that KBiO3 combined with proper amount of BiOCl nanosheets exhibited high efficiency in the photocatalytic process, and BiOCl/KBiO3 with the molar ratio of 70/30 demonstrated the highest photocatalytic activity due to its large surface area, excellent charge separation characteristics and the suppressed recombination of electron-hole pairs. The results of active species detection reveal that the superoxide radical anions (O2-), hydroxyl free radicals (·OH), photogenerated holes (h+) and photogenerated electrons (e-) reactive species work together for the photocatalytic degradation of RhB. A possible and new mechanism of photocatalysis that differs from other teams was also explored and proposed. The present study will benefit the development of the new p-n heterojunction photocatalysts and would be of great importance to meet ever-increasing environmental demands in the future.

Keywords

• BiOCl/KBiO3
• p-n heterojunction
• photocatalytic activity
• visible light
• photocatalytic mechanism