Synthesis of flower-like Bi2Sn2O7/Bi2WO6 hierarchical composites with enhanced visible light photocatalytic performance

Flower-like Bi2Sn2O7/Bi2WO6 hierarchical composites with Bi2Sn2O7 nanoparticles on Bi2WO6 nanosheet by different Bi2Sn2O7 contents were synthesized via a facile two-step hydrothermal method. The composite of Bi2Sn2O7/Bi2WO6 exhibits higher photocatalytic activity toward Rhodamine B (RhB) under visible light than pristine Bi2WO6 and Bi2Sn2O7. Comparatively, 7% Bi2Sn2O7/Bi2WO6 showed the highest photocatalytic activity owing to the best separation efficiency of photogenerated charges. The role of the active species in the process of the degradation is evaluated by using different types of active species scavengers which revealed that the holes (h(+)) and hydroxyl radicals ((OH)-O-center dot) were the main active species responsible for the photodegradation of RhB. The photocatalytic mechanism is further proposed based on impedance spectroscopy (EIS) and the calculated energy bands by Mott-Schottky plot, which unfolds the charge transfer and the active species formed in the photocatalytic process. Furthermore, the as-obtained photocatalysts showed good photocatalytic activity after three recycles. (c) 2019 Elsevier B.V. All rights reserved.