Study on the piezophotocatalytic hydrogen evolution coupling tetracycline degradation performance and mechanism of ZnFe₂O₄/NaNbO₃ composite nanorods

Utilizing solar energy and mechanical vibration energy for hydrogen production while simultaneously degrading pollutants is a highly promising strategy to address energy shortages and environmental pollution. Traditional photocatalytic hydrogen production relies on hole scavengers and co-catalysts, leading to resource waste and increased costs. In this study, one-dimensional ZnFe₂O₄/NaNbO₃ composite nanorods were prepared via a hydrothermal-sintering method. Narrow band-gap ZnFe₂O₄ was in-situ grown on the surface of piezoelectric NaNbO₃ nanorods, achieving deep synergy among broadened visible-light response, piezoelectric effect, and S-scheme charge transfer. This system eliminates the need for expensive sacrificial agents and co-catalysts. By employing Tetracycline (TC) as the hole scavenger, it achieves concurrent high-efficiency hydrogen evolution and pollutant degradation. Photoelectrochemical, XPS, and radical trapping results confirm that the built-in electric field drives directional electron transfer from NaNbO₃ to ZnFe₂O₄, following an S-scheme transfer mechanism. The one-dimensional nanorods provide a rapid electron transport channel, while the ultrasound-induced piezoelectric field tilts the energy bands of NaNbO₃, accelerating charge carrier separation and migration. Under photo-ultrasound synergy, 20ZnFe₂O₄/NaNbO₃ exhibited an H₂ evolution rate of 723.3 μmol·h⁻¹·g⁻¹ and 79.6% TC degradation. In the coupled H₂ evolution-degradation system, theH₂ production rate reached 357.36 μmol·h⁻¹·g⁻¹ over 5 h with 66.4% simultaneous TC degradation. This work demonstrates the synergistic enhancement mechanism between the S-scheme heterojunction and piezoelectric effect, offering insights for designing efficient, dual-functional piezo-photocatalysts free of sacrificial agents and co-catalysts.