In situ construction of oxygen-vacancy-rich Bi0@Bi2WO6-x microspheres with enhanced visible light photocatalytic for NO removal

Surface oxygen vacancy defects and metal deposition on semiconductor photocatalysts play a critical role in photocatalytic reactions. In this work, oxygen-deficient Bi2WO6 microspheres have been prepared by a facile ethylene glycol-assisted solvothermal method. Bi-0 nanoparticles were reduced by in situ thermaltreatment on Bi2WO6 microspheres to obtain Bi-0@Bi2WO6-x, as well as maintaining the oxygen vacancies (OVs) under N-2 atmosphere. Afterwards, photocatalytic NO oxidation removal activities of these photocatalysts were investigated under visible light irradiation and Bi-0@Bi2WO6-x shows the best NO removal activity than other samples. The photogenerated charge separation and transfer are promoted by Bi-0 nanoparticles deposited on the surface of semiconductor catalysts. OVs defects promote the activation of reactants (H2O and O-2), thereby enhancing the formation of the active substance. Moreover, both OVs defects and Bi-0 metal have the characteristics of extending light absorption and enhancing the efficient utilization of solar energy. Besides, the photocatalytic NO oxidation mechanism of Bi-0@Bi2WO6-x was investigated by in situ FTIR spectroscopy for reaction intermediates and final products. This work furnishes insight into the synthesis strategy and the underlying photocatalytic mechanism of the surface-modified Bi-0@Bi2WO6-x, composite for pollutants removal. (C) 2021 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.