Enhancement of photocatalytic properties of nanosized La2Ti2O7 synthesized by glycine-assisted sol-gel route

A photochemical route in the synthesis and characterization of La2Ti2O7 and La2Ti2O7/AgO films and its evaluation in Congo red degradation and as antibacterial control to Staphylococcus aureus

In this article, we propose a simple photochemical method to synthesize pure La2Ti2O7 films and La2Ti2O7 films doped with silver at 1.0, 3.0, and 5.0 mol%. After annealing the photo-deposited films at 900 °C, XRD, SEM, and XPS analyses showed the formation of a monoclinic La2Ti2O7 phase and the presence of Ag and AgO in doped samples. Photocatalytic tests for Congo red degradation demonstrated that pure La2Ti2O7 achieved 25.4% degradation, while doped samples reached a maximum of 92.7% degradation. Moreover, increasing silver doping on La2Ti2O7 films significantly reduced the growth of Staphylococcus aureus, indicating potential antibacterial properties. The enhanced photoactivity was attributed to the formation of a type I heterojunction between La2Ti2O7 and AgO, and a degradation mechanism was proposed based on Congo red degradation.

La2Ti2O7 nanosheets modified by Pt quantum dots for efficient NO removal avoiding NO2 secondary pollutant

Two-dimensional La₂Ti₂O₇ nanosheets with regular morphology and good dispersion were prepared by the hydrothermal method under a magnetic field. Zero-dimensional Pt quantum dots (Pt-QDs) were loaded on the La₂Ti₂O₇ nanosheets. The electron-hole separation and carrier transfer in the Pt-loaded La₂Ti₂O₇ nanosheets were significantly enhanced. The La₂Ti₂O₇ nanosheets loaded with 3 wt% Pt-QDs exhibit the largest NO removal efficiency of 51% and less than 3.2 ppb NO₂ intermediate pollutant in 30 min. The high photocatalytic ability was attributed to the surface plasmon resonance in Pt-QDs and the enhanced electron-hole separation. A large number of e^-, h⁺, •OH and •O₂^- active species were formed on the surface of Pt-loaded La₂Ti₂O₇ nanosheets under light irradiation. The conversion pathway from NO to NO₃^- was verified by the in situ diffuse reflectance infrared Fourier-transform spectroscopy and DFT calculation. This work supplies a feasible approach to responsive photocatalysts for efficient, stable, and selective NO removal avoiding the NO₂ secondary pollutant.