In situ construction of oxygen-vacancy-rich Bi~0@Bi_2WO_(6-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 Bi_2WO_6 microspheres have been prepared by a facile ethylene glycol-assisted solvothermal method.Bi~0 nanoparticles were reduced by in situ thermaltreatment on Bi_2WO_6 microspheres to obtain Bi~0@Bi_2WO_(6-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@Bi_2WO_(6-x) shows the best NO removal activity than other samples.The photogenerated cha rge separation and trans fe r are promoted by Bi~0 nanoparticles deposited on the surface of semiconductor catalysts.OVs defects promote the activation of reactants(H_2 O 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@Bi_2WO_(6-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 mecha nism of the surfacemodified Bi~0@Bi_2WO_(6-x) composite for pollutants removal.