Controlled engineering of tunable 3D-BiOX (X = Cl, Br) hierarchical nanostructures via dopamine-mediated synergetic interactions for efficient visible-light absorption photocatalysis

Abstract

Integration of surface tunable 3D-BiOX hierarchical nanostructures (HNS) from size and facet controlled ultra thin 2D-nanosheets in aqueous solutions under an environmental benign process is remains a challenge. Because of their visible light response is highly depending on structural characteristics and yet most fabrications are involved hydrothermal methods. Herein, a simple dopamine-mediated bioinspired approach is proposed to integrate surface tunable 3D-BiOCl, 3D-BiOBr and 3D-BiOCl0.875Br0.125 hierarchical microspheres assembled by ultra thin 2D-nanosheets in aqueous solutions under mild conditions. The biomolecule dopamine (DA.HX) here played a multiple role as reactant, template and halogen source for 3D-BiOX materials, and its amount precisely controlled surface textural properties and nanosheets thickness with exposed (001) facets. Interestingly, the interfacial surface chelate interactions of dopamine facilitated the band-edge shift towards visible range along with surface induced oxygen defect impurities, which effectively reduced their forbidden bandwidth for extended visible light absorptions and photoluminescence quenching with an efficient charge separations. The photocatalytic activities of resulting 3D-BiOX HNS have shown excellent Rhodamine B degradation provided by highly oxidative h+ and surface induced oxygen vacancies acted as e- trapping centers to generate highly active O2− radicals for selective benzyl alcohol oxidation with high photostability and recyclability than their bare BiOX materials.