Innovative TiO₂–SiO₂–La₂O₃ nanocomposite systems for enhanced wastewater treatment performance

An ellipsoidal TiO 2 -SiO 2 -La 2 O 3 nanocomposite was successfully synthesized via a wet impregnation method. To our knowledge, this work presents the first rational design and synthesis of a novel ternary TiO 2 -SiO 2 -La 2 O 3 nanocomposite. Energy-dispersive X-ray spectroscopy (EDS) in conjunction with scanning electron microscopy (SEM) demonstrated efficient nanoscale fabrication for the associated catalysts with a mean particle size of 45 nm. A direct optical band gap of 2.88 eV was obtained from UV–vis, which is consistent with visible-light photocatalytic activity. FTIR identified characteristic bands at 1070 cm⁻¹ (Si–O–Si asymmetric stretching) and 498 cm⁻¹ (Si–O–Ti bending), while Raman spectroscopy confirmed the anatase phase (bands at 142, 198, 395, 515 and 638 cm⁻¹). X-ray diffraction (XRD) showed a single crystalline anatase phase, with SiO 2 present in amorphous form, and the Scherrer equation was used for crystallite-size analysis. The average crystallite size was 38.16 nm, which was in good agreement with the particle sizes measured by SEM (45 nm). TGA confirmed the composite withstands high temperatures. TEM revealed that the nanocomposite had a well-defined ellipsoid shape and a size of 66 nm, confirming the creation of a nanocomposite. The composite's BET surface area was approximately 16.0 m²/g, its pore volume was 0.10 cm³/g, and its average pore size was around 317 Å; the synthesis influenced the specific surface area. To evaluate photocatalytic activity, malachite green (MG) degradation was observed. The composite degraded 93.87% of MG during two hours of sunlight, making it a viable photocatalyst for breaking down organic dye pollution. These findings showed that the nanocomposite might be used as a possible photocatalyst for the degradation of organic dye pollutants.