Hybrid bismuth oxyhalides@gypsum as self-cleaning composites: novel aspects of a sustainable photocatalytic technology for solar environmental cleanup

Herein we report the fabrication of a novel heterojunctioned BiOCl_xBr_1-x@gypsum composite and its application as a self-cleaning surface for the straightforward use in construction and building materials. The morphology, chemical composition and crystal structure of the hybrid material were characterized using X-ray diffraction and scanning electron microscopy. The photocatalytic activity of the new composite was investigated for the degradation of naphthalene and rhodamine B (RhB) under visible light (λ ≥ 420 nm) irradiation. Our results show rapid and complete destruction of the RhB dye after only 4 minutes under Xe visible light irradiation (422-740 nm) and 2.5 minutes under mild sunlight illumination. Total organic carbon measurements could verify the absolute mineralization of the recalcitrant naphthalene contamination, as a state of the art example, within 20 minutes of visible light illumination.