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

Abstract 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.