Coupling of solid-solution and heterojunction in a 2D-1D core-shell-like BiOClI/BiOI hierarchy for promoting full-spectrum photocatalysis and molecular oxygen activation.

We herein describe the coupling of solid-solution and heterojunction in a 2D-1D BiOClI/BiOI hierarchical architecture for optimizing photoabsorption, energy band levels and charge separation, thereby promoting the photo-oxidation and molecular oxygen activation performance. BiOClI/BiOI shows a core-shell-like structure with BiOClI thin nanoflakes (∼3 to 8 layers) homogeneously vertical coating on the surface of BiOI strips. The photo-responsive range of BiOClI/BiOI can be orderly tuned from 450nm to 650nm by increasing the BiOClI content. Regardless of visible light (λ>420nm) or UV light (365nm) irradiation, BiOClI/BiOI casts highly promoted photocatalytic activity in decomposing methyl orange (MO) compared to the BiOClI and BiOI. This enhancement on full-spectrum photoreactivity is attributable to the facilitated charge separation derived from BiOClI/BiOI heterojunction with intimate interfacial interaction, which is approved by transient photocurrent response under visible and UV-vis light. To probe the photocatalytic mechanism, active species trapping tests are performed over BiOClI, BiOI and BiOClI/BiOI, which reveal superoxide radical (O) and hole (h) take dominant roles in photo-oxidation reaction. BiOClI/BiOI was also found possessing a stronger ability in molecular oxygen activation with a O production rate of 2.22×10molLh, which far outperforms BiOI (1.35×10molLh) and BiOClI (1.54×10molLh). It further corroborates the efficient band charge transfer between BiOClI and BiOI. This work may furnish a new concept on smart design of high-performance photocatalytic materials via manipulating multiple strategies.