Synergistic effect of Li, La co-doping on photocatalytic activity of BaTiO₃ ferroelectric material for effective degradation of toxic NO_x for environmental remediation

We investigated the synergistic effects of Li, La-doping and co-doping on the A-site of perovskite BaTiO₃ microstructure as a catalyst for the removal of toxic NO_x for environmental remediation. The Rietveld refinement of XRD and Raman analysis confirmed that at room temperature, the ceramic samples possessed a pure-tetragonal perovskite structure, with P4mm space group. SEM images revealed a denser microstructure with reduced grain size on Li, La doping in BaTiO₃. XPS results confirmed the coexistence of Li and La as doping elements into BaTiO₃ lattice. EPR and PL spectra demonstrate the presence of Ti and Ba vacancies as well as defects. According to the DRS results, the absorption edge of the co-doped sample was blue-shifted. In frequency-dependent dielectrics, the co-doped sample exhibits the greatest rise in dielectric permittivity. Impedance measurement demonstrates the fastest rate of charge transport in Ba_0.98Li_0.01La_0.01TiO₃. Similarly, Li and La incorporation into BaTiO₃ significantly reduced the recombination extent of charge carriers as evidenced by the PL. Under UV light, the photocatalytic NO_x degradation with Ba_0.98Li_0.01La_0.01TiO₃ achieved a remarkable 44 % efficiency during 60 min. This enhancement is associated with improved charge carrier separation at the interface between the ferroelectric surfaces. Only a marginal decrease in photocatalytic activity occurred after four consecutive runs. A reasonable photocatalytic mechanism for the degradation of NO_x over Ba_0.98Li_0.01La_0.01TiO₃ is proposed. This study's findings can inspire the design and synthesis of rare earth and alkali metal ion co-doped photocatalysts with built-in electric fields of a ferroelectric material for efficient NO_x removal from the environment.