Engineering design of hierarchical g-C3N4@Bi/BiOBr ternary heterojunction with Z-scheme system for efficient visible-light photocatalytic performance

Novel g-C3N4@Bi/BiOBr ternary heterostructured composites were successfully fabricated by a facile solvothermal method, in which ethylene glycol functioned as both a solvent and a reductant. As observed by scanning electron microscopy (SEM), Bi/BiOBr nanoplates were embedded on the surface of layered g-C3N4 to form three-dimensional hierarchical structure. Under visible-light irradiation, the ternary g-C3N4@Bi/BiOBr composites displayed notably boosted photocatalytic performance for photodegrading tetracycline and rhodamine B. As revealed via the UV-visible diffuse reflection spectra (UV-vis DRS) and photocurrent experiments, the three-dimensional hierarchical structure obviously enhanced the visible-light photoresponse and the ternary heterojunction greatly promoted the separation of photo-induced carriers, thus leading to the high photocatalytic performance. Based on the results of trapping radical experiments and the energy band potentials, an indirect Z-scheme system was proposed to illuminate the possible photodegradation mechanism. This work provides a novel strategy to design the multiple heterostructured photocatalysts with high efficiency for environmental purification and energy conversion. (C) 2019 Elsevier B.V. All rights reserved.