Room-Temperature\nSynthesis of Flower-Like BiOX (XCl,\nBr, I) Hierarchical Structures and Their Visible-Light Photocatalytic\nActivity

Abstract

A simple method for facile synthesis\nof three-dimensional (3D)\nbismuth oxyhalide (BiOX, XCl, Br, I) hierarchical structures\nat room temperature has been developed. Under the influence of l-lysine surfactant, the bismuth and halogen (Cl, Br, I) sources\nhydrolyze and self-assemble into flower-like hierarchical architectures\nwithin 10 min. The resulted materials were characterized by XRD, FESEM,\nTEM, UV–vis DRS, and N₂ adsorption–desorption\ntechniques. We found that l-lysine is indispensable for their\nformation and the amount of HX has great effect on the final morphology.\nThe BiOX (XCl, Br, I) hierarchical architectures are composed\nof single-crystalline nanoplates. We propose an amino-and-carboxyl\nstructure-directing mechanism for the formation of the hierarchical\nstructures. To evaluate the photocatalytic activity of the as-prepared\nmaterials, rhodamine-B was employed as a probe dye for degradation\nunder visible light. All of the BiOX (XCl, Br, I) with 3D\narchitectures show higher photocatalytic activities than their sheet-like\ncounterparts. The superior activity is ascribed to the better light-harvesting\ncapacity of the 3D hierarchical structures. The adopted method can\nbe applied for large-scale generation of novel structures of similar\nkinds in a facile manner.