Hydrothermal Synthesis of ZrO2 Nanoparticles: Study on Structural, Optical, Morphology Properties and Photocatalyst Activity

In this study, zirconium oxide (ZrO₂) nanoparticles were synthesized using the hydrothermal method at sintering temperature of 400, 500, 600, and 700°C. The synthesized nanoparticles were characterized by various techniques, including UV-Visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), Photoluminescence (PL), Brunauer–Emmett–Teller (BET), Electron Spin Resonance (ESR), X-ray diffraction (XRD), and Scanning Electron Microscopy (SEM). The XRD pattern confirmed the formation of tetragonal phase for all sintering temperatures, with the crystal size reaching a minimum of 5.5 nm at 600°C and slightly increasing to 5.9 nm at 700°C. The blue shift of the absorption edge from 372 nm at 400°C to 376 nm at 700°C implies a modification in the particle size. SEM and EDX confirmed the uniform distribution and high purity of the nanoparticles. FT-IR analysis identified the absorption peaks of the Zr–O–Zr extension with moisture content. The BET isotherm demonstrates gradual adsorption at low pressure, with sharp rise at P/P₀ = 1, indicating capillary condensation in mesopores. Photocatalytic degradation of methyl blue (MB) dye under sunlight irradiation demonstrated high efficiency, with ZrO₂ synthesized at 600°C exhibiting the best photocatalytic activity. The catalyst also showed good reusability, with only a slight decrease in degradation efficiency after four cycles. Overall, the study demonstrates the potential of ZrO₂ nanoparticles as effective photocatalysts for environmental remediation.