New insights into atomic layer BiOBr quantum dot/ZnAl-LDH composites in photocatalytic water treatment: Performance and mechanism

Abstract

Insufficient absorption sites and low charge separation notably limit the activation of photocatalytic molecular oxygen. In this study, atomic-layer BiOBr (BiOBr-QDs)/ZnAl-LDH composites with a considerable number of edges were developed to address the above-mentioned problems. The result of this study indicated the spatial separation of atomic-layer BiOBr-QDs/ZnAl-LDH's conduction band maximum (CBM) and valence band minimum (VBM). As a result, holes were produced on the substrate surface based on irradiation, and electrons were generated at the sites of the edge, such that ultra-fast charge separation can be carried out. The edges exposed massive adsorption sites in terms of oxygen molecules. Thus, electrons at the sites of the edge led to the reduction of absorbed oxygen molecules, thus exhibiting stronger photocatalytic •O2− production. Furthermore, the result confirmed that the atomic layer BiOBr-QDs/ZnAl-LDH are promising in environmental catalytic degradation for its increased activity of •O2− production. In this study, a novel insight into advanced photocatalyst design based on edge unsaturated ligand engineering at an atomic level is provided.