B doped Bi2O2CO3 hierarchical microspheres: Enhanced photocatalytic performance and reaction mechanism for NO removal.

[Display omitted] • A new strategy of B doping in Bi 2 O 2 CO 3 (B-BOC) was developed. • The B doping leads to the formation of intermediate levels and electronic channels. • The photocatalytic elimination of NO in air was promoted via B doping. • The electron localization induced by B doping can directly activate O 2 and NO molecules. • The combined in-situ FRIFT and DFT reveals mechanism of photocatalytic NO oxidation. Challenges are remaining in preparation of photocatalysts with efficient separation of charge carriers and utilization of visible light, and understanding of the reaction mechanism. In this work, B-doped Bi 2 O 2 CO 3 hierarchical microspheres were prepared by one-step hydrothermal treatment using bismuth citrate and sodium tetraborate as precursors. Compared with pure Bi 2 O 2 CO 3 , the B-doped Bi 2 O 2 CO 3 exhibited high visible-light photocatalytic activity of removing NO to achieve efficient air purification. Combined with experiments and DFT calculations, the doped-B could induce the formation of the intermediate level near the valence band, thus increasing the visible light absorption. The B-doping could also promote the separation of electron-hole pairs and enhance the activation of reactants. Therefore, plentiful reactive could be generated and detected by ESR via the reaction between the activated small reactant molecules and separated photogenerated carriers. To reveal the reaction mechanism of photocatalytic NO oxidation, the in-situ DRIFTS method was used to study the reaction processes, and an important intermediate NO 2 + was found. The presence of NO 2 + participated in the reaction enabled favorable formation for the final product of nitrates. This work could provide a new strategy for the improvement of photocatalytic efficiency. [ABSTRACT FROM AUTHOR]