Enhanced durability of nitric oxide removal on TiO2 (P25) under visible light: Enabled by the direct Z-scheme mechanism and enhanced structure defects through coupling with C3N5

Abstract Direct Z-scheme catalysts have become main “stars” of the photocatalytic field because of their excellent redox ability. Herein, a direct Z-scheme catalyst of TiO2(P25)-C3N5 with enhanced structural defects was designed, which exhibited excellent activity and durability in visible-light-driven (λ > 400 nm) NO photooxidation (450 ppb) under the relative humidity (RH) of 15 %. After 6 continuous runs, the NO removal efficiency only shows 7.0 % of loss from 67.1 %–60.1 %, while that using TiO2 and C3N5 declines 29.2 % and 5.1 %, respectively. In situ NO DRIFTS results confirm the main products of NO photooxidation in the system involving TiO2-C3N5 to be NO2 and NO3−. Moreover, under the higher RH of 50 % and 80 %, TiO2-C3N5 still exhibited the better activity and ndurability for NO photooxidation than P25 and C3N5. This work demonstrates a new direct Z-scheme catalyst with efficient NO photooxidation ability, which may help for constructing high-efficiency photocatalysts for controlling NOx.