Photodegradation of NO with minimal NO₂ secondary pollution by La₂Ti₂O₇ nanosheets loaded with Ag particles

Lanthanum titanate (LTOM) nanosheets with regular morphology and good dispersion were prepared by a hydrothermal method under magnetic field of 240 mT. Ag particles with different sizes from several nanometers to tens of nanometers were loaded on the LTOM surface to be Schottky contact. The LTOM nanosheets loaded with 7 wt% Ag exhibit the largest NO removal efficiency of about 46 % and produce only 6.0 ppb NO₂ secondary pollution in 15 min, which increases by 48% and reduces by 88% in comparison with the pure LTOM. The improved photocatalytic performance is attributed to the broadened light harvest in the visible range, enhanced spatial separation of photoinduced charge carriers by the Schottky contact and surface plasmon resonance in zero-dimensional Ag nanoparticles. A large number of e⁻, h⁺, ·OH, ·O₂⁻ and ¹O₂ radicals are generated as active reaction sites under light irradiation, playing key roles in the NO photodegradation reaction. Moreover, the composite photocatalysts enjoy good stability and repeatability without obvious photodegradation reduction after several cycles of photocatalytic reaction. The photocatalysis mechanism is eventually proposed on the basis of trapping experiments and in situ DRIFTS measurements.