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.

Automated summary

This study prepared oxygen-deficient Bi2WO6 microspheres and deposited Bi-0 nanoparticles on the surface, enhancing photocatalytic activity. Bi-0@Bi2WO6-x exhibited the best NO removal activity under visible light irradiation. The presence of Bi-0 nanoparticles promoted photogenerated charge separation and transfer, while OVs defects facilitated reactants activation and active substance formation.