Construction of oxygen vacancy on Bi12O17C12 nanosheets by heat-treatment in H2O vapor for photocatalytic NO oxidation

Oxygen-vacancies (OVs) play significant roles in semiconductor-based photocatalysis, such as elevating light absorption property, photogenerated carries separation efficiency, molecular activation, and photocatalytic activity. However, heat-treatment of semiconductors in dangerous H-2 atmosphere is usually indispensable for OVs formation. In this work, C-doped Bi12O17C12 nanosheets were facially heat-treated in H2O vapor (similar to 2.3 vol%) mixed with Ar at 300 degrees C to in-situ introduce OVs by the proposed reactions of C(s) + H2O(g) -> CO(g) H-2(g) + O-Lattice -> H2O(g) + OV. The formation of OVs, which was confirmed by electron paramagnetic resonance (EPR), can narrow the band gap, and enhance the photogenerated e(-)/h(+) separation efficiency on Bi12O17C12. Moreover, OVs-rich Bi12O17C12 nanosheets can facilitate molecular O-2 activation and produce more reactive oxygen species (ROS), especially O-1(2), which greatly improve the NO to NO3- conversion efficiency with NO removal rate of similar to 63% and NO3- production selectivity of similar to 92.6 %. The present work will bring new insights into the construction and roles of OVs in semiconductor-based photocatalysis. (C) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.