Improved piezo-catalysis through integration of dual-active semiconductors in a NaNbO3/MoS2 heterojunction for degradation of rhodamine B dye and ofloxacin antibiotic, and Cr(vi) reduction

Abstract

Piezocatalysis has emerged as a promising and sustainable method for degrading hazardous contaminants in aqueous environments. Here, a NaNbO₃/MoS₂ (NbO/MS) hybrid heterojunction is developed, exhibiting exceptional multifunctional piezo-catalytic activity for removing organic and inorganic pollutants. Under ultrasonic vibration, the NbO/MS-3 nanocomposite achieves degradation efficiencies of 88.1% for rhodamine B in 120 minutes, 80.1% for ofloxacin in 90 minutes, and 83.0% for reduction of Cr(VI) to Cr(III) ions in 90 minutes, with rate constants 3.1, 2.1, and 5.65 times higher, respectively, than those of pure NbO. The enhanced performance results from forming an effective heterojunction that helps separate charge carriers and increases the production of reactive oxygen species (˙OH and ˙O₂⁻), as confirmed by scavenger tests and EPR spectroscopy. Moreover, the nanocomposite displays excellent recycling stability and structural durability over five consecutive uses. This study offers a rational design for piezo-catalysts to degrade dyes and antibiotics, and reduce toxic heavy metal ions, providing a green and efficient approach for treating complex wastewater systems.