Environmental and clinical applications of Cymbopogon-derived TiO2:WO3 nano-cubes

Nano-cubes of TiO2 and WO3: TiO2 was prepared using Cymbopogon extract. Cymbopogon, also known as lemongrass, is an essential plant that contains a variety of vital phytochemicals, including citral, geraniol, and citronella. The TiO2 and WO3:TiO2 nano-cubes observed by scanning electron microscopy (SEM) were verified by energy-dispersive X-ray (EDX) spectroscopy. Fourier transform infrared spectroscopy has revealed the successful fabrication of WO3, TiO2, and WO3:TiO2 nano-cubes. The X-ray diffraction (XRD) peaks at 2θ = 24.4°, 24.5°, 25.3°, and 29.2°, corresponding to the (002), (020), (200), and (112) planes, confirm the monoclinic WO₃ phase. Peaks at 25.8°, 38.3°, and 38.6°, corresponding to (101), (004), and (112) planes, indicate the anatase TiO2 and TiO2/WO3 phases, while peaks at 44.9°, 55.0°, and 64.0°, corresponding to the (210), (220), and (310) planes, clearly indicate the rutile TiO₂ phase. The crystallite sizes of WO₃, TiO₂, and the WO₃:TiO₂ nano-cubes (1:1 and 2:1) were 51 nm, 41 nm, 48 nm, and 57 nm, respectively.UV–Vis spectroscopy revealed energy band gaps of 3.16 eV for TiO2, 2.47 eV for WO3, and 2.90 eV and 2.94 eV for the WO3: TiO₂ (1:1 and 2:1) nano-cubes, respectively. Under solar irradiation, the synthesized samples rapidly degraded methylene blue (MB). The WO3:TiO2 nano-cubes also showed effective antibacterial activity against Bacillus subtilis and Pseudomonas aeruginosa. These results suggest that TiO2: WO3 nano-cubes are promising materials for environmental remediation and antimicrobial applications.