One-pot hydrothermal synthesis of FeNbO₄ microspheres for effective sonocatalysis

FeNbO₄ sonocatalysts were successfully synthesized by a simple hydrothermal route at pH values of 3, 5, 7, 9 and 11. The catalysts were characterized by XRD, XPS, TEM, SEM, N₂ adsorption and DRS to analyse the effect of pH parameters on the physicochemical properties of the materials during hydrothermal synthesis. The sonocatalytic activity of FeNbO₄ microspheres was evaluated by using acid orange 7 (AO7) as the simulated contaminant. The experimental results showed that the best sonocatalytic degradation ratio (97.45%) of organic dyes could be obtained under the conditions of an initial AO7 concentration of 10 mg L^-1, an ultrasonic power of 200 W, a catalyst dosage of 1.0 g L^-1, and a pH of 3. Moreover, the sonocatalysts demonstrated consistent durability and stability across multiple test cycles. After active species capture experiments and calculation of the energy band, a possible mechanism was proposed based on the special Fenton-like mechanism and the dissociation of H₂O₂. This research shows that FeNbO₄ microspheres can be used as sonocatalysts for the purification of organic wastewater, which has a promising application prospect.