Ultrasound-Fabricated BaZrO 3 Nanoneedles for Degradation of Hazardous Organic Dyes

Abstract Ultrasound-assisted cavitation was used to synthesize BaZrO3 nanoneedles. Ultrasonic energy facilitated uniform mixing and anisotropic growth along the c-axis, resulting in a needle-like shape. The synthesized BaZrO3 nanoneedles were characterized using X-ray diffraction (XRD) for phase and crystallinity, Fourier-transform infrared spectroscopy (FTIR) for functional groups and chemical bonds, Ultraviolet-Visible diffuse reflectance spectroscopy (UV-Vis DRS) to assess optical absorption and estimate the band gap, photoluminescence (PL) spectroscopy to analyze charge-carrier recombination, and field-emission scanning electron microscopy (FESEM) along with dispersive X-ray spectroscopy (EDX) for elemental composition. TEM and FESEM images confirmed the needle-shaped morphology and size of the nanostructures. This morphology contributed to faster degradation under natural sunlight. Their high photocatalytic efficiency arises from the anisotropic nanoneedle shape, which provides a large active surface area and promotes rapid charge transport, along with advantageous optical properties such as strong sunlight absorption and reduced electron–hole recombination. Overall, these features enable faster reaction kinetics, making BaZrO3 nanoneedles a highly effective and durable photocatalyst for degrading both cationic and anionic pollutants. The photocatalytic performance was tested on two organic dyes: the cationic dye Rhodamine B (RhB) and the anionic dye Indigo Carmine (IC). The nanoneedles achieved 99.5% degradation of RhB in 50 min and 98% of IC in 60 min, demonstrating excellent photocatalytic activity. These results confirm that BaZrO3 nanoneedles are efficient photocatalysts for rapidly breaking down both cationic and anionic dye pollutants under sunlight.