Nb ₂ CT _x @UiO-66-Bi ₂ Fe ₄ O ₉ Ternary Hybrid for Efficient Piezo-photocatalytic Removal of Sulfamethoxazole from Water

The widespread and uncontrolled use of antibiotics poses significant dangers and challenges in water treatment and public health. A three-component nanocomposite, Nb 2 CT x @UiO-66-Bi 2 Fe 4 O 9, was rationally assembled via a straightforward hydrothermal mixing approach to combine photocatalytic and piezoelectric effects for the efficient decomposition of the antibacterial sulfamethoxazole (SMX). The morphological, chemical, and surface properties of the materials were tested by electron microscopic tools, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman microspectroscopy, Fourier transform infrared spectroscopy (FTIR), and energy dispersive X-ray spectroscopy (EDS), which confirmed the tight interfacial bonding between the three components, while electrochemical impedance spectroscopy (EIS), photoluminescence (PL), and Mott–Schottky assessments revealed enhanced charge transfer transitions. The elevated performance originates from the coactive piezoelectric photocatalysis in which piezoelectric Bi 2 Fe 4 O 9 generates a polarization field under the action of ultrasound to promote charge separation, Nb 2 CT x acts as a conductive and stable mediator, and UiO-66 enhances pollutant adsorption and interfacial charge transport. In addition, Nb 2 CT x @UiO-66-Bi 2 Fe 4 O 9 still possesses high photocatalytic performance at various pH values, pollutant concentrations, and water sources. In combination with ultrasonic vibration and visible light irradiation, Nb 2 CT x @UiO-66-Bi 2 Fe 4 O 9 achieved 91.1% SMX degradation within 160 min and 98.2% within 30 min under the combination of UV light and ultrasonic quivering. The catalyst retained approximately 89.4% of its original activity after five consecutive cycles, demonstrating excellent durability. Therefore, this study demonstrates that the as-prepared Nb 2 CT x @UiO-66-Bi 2 Fe 4 O 9 catalyst holds great potential for environmental remediation.