Effective removal of atmospheric NO has raised worldwide interest owing to environmental issues e.g., photochemical smog, acid rain and ozone pollution. With an unpaired electron (π*2py)1}, NO is chemically active and reacts with oxygen readily. However, the reaction activity significantly descends when the concentration of NO is lower than the ppm, and its long-term exposure even at a low level (the indoor concentration of NO is 200 ppb) still causes serious respiratory diseases. Thus, it is urgent to develop environmentally friendly methods to remove NO at the level of hundreds of ppb in indoor circumstances. Herein, porous Bi@Bi2Ti2O7 with a rich-oxygen vacancy (Vo) was fabricated via a one-pot hydrothermal method. Specific UV, Vis, and NIR LED laser irradiation experiments to evince that as-prepared Bi@Bi2Ti2O7-Vo possesses full spectrum responsive photocatalytic activity. Remarkably, the optimized composite photocatalyst exhibited a photocatalytic efficiency of 79%, more than double higher than that of its counterpart, Bi2Ti2O7 (31.79%), for removing ppb-level NO in continuous flow under visible-near infrared (Vis-NIR) irradiation (λ > 420nm). The enhanced photocatalytic performance was attributed to the synergistic effect of plasmonic Bi (ca. 2 nm) and Vo, which was revealed by control experiments and theoretical calculations. The presence of Bi and Vo benefits the adsorption and photocatalytic activation of NO (NO(g)→NO*→NO2 *→NO3*) as supported by DFT calculations. Moreover, Bi not only broadens light absorption to near infrared, but also inhibits the generation of toxic intermediates and alleviates the inactivation of Bi@BT-Vo-4. Furthermore, the adsorption and photocatalytic conversion pathway of NO was explored by in situ DRIFTS, suggesting that NO+ as intermediate species is crucial to improve the selectivity of NO converting to nitrate. This work provides a new perspective on constructing full-spectrum-driven photocatalysts for environmental remediation.
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