Hydrothermal preparation of crystalline lithium niobate photocatalysts for effective degradation of dye-containing contaminated wastewater by ultraviolet to visible light irradiation

This study investigates the synthesis and photocatalytic properties of lithium niobate. X-ray diffraction (XRD) analysis reveals that a 48-h synthesis yields lithium niobate with a superior crystalline structure compared to 24-h and 12-h samples, evidenced by a smaller full width at half maximum (FWHM). Optimal Nb₂O₅/LiOH ratios of 3:5.7 result in a pure lithium niobate phase, while deviations lead to Nb₂O₅ or unidentified phases, corroborated by SEM observations of square lithium niobate structures at the ideal ratio and irregular forms at others. Under UV irradiation in the first hour, lithium niobate exhibits rapid degradation of methylene blue at 82.04%, twice as fast as TiO₂, surpassing the efficiency of TiO₂. In addition, lithium niobate significantly outperformed TiO₂ in degrading methyl blue up to 67.14% under visible LED irradiation during the first hour, while TiO₂ showed no degradation effect. This demonstrates its exceptional degradation characteristics and potential for enhanced photocatalytic applications.