Photocatalytic performance enhanced via surface bismuth vacancy of Bi6S2O15 core/shell nanowires

Core/shell structured Bi6S2O15 nanowires with surface bismuth defects are fabricated via a one-step hydrothermal method. The UV photocatalytic activity of the defective Bi6S2O15 nanowires is about 4 times as high as that of pure Bi6S2O15 nanowires. The light response range of Bi6S2O15 nanowires is greatly expanded from 370 rim to 450 nm via surface bismuth-vacancy. The main oxidative species transform from holes (h(+)) to the superoxide radical (center dot O-2(-)) and hydroxyl radicals (center dot OH) owing to the great changes of the electronic structure of vacancy Bi6S2O15. Surface bismuth vacancies elevate the conduction band (CB) and introduce impurity states above the valence band (VB) of Bi6S2O15. The higher potential of CB benefits for the production of superoxide radical (center dot O-2(-)) and the hydroxyl radicals is result from the surface hydroxide radical defects formed with the introduction of surface bismuth-vacancy. The enhancement in photocatalytic performance is attributed to the high separation efficiency of photoinduced electron-hole pairs due to the broadening of the valence band (VB), and the extending of photoresponse is result from the narrowing of energy band gap owing to the rise of the valence band maximum (VBM). (C) 2015 Elsevier B.V. All rights reserved.