Long-term stable piezocatalytic degradation via bulk LiNbO3 single-crystal

Abstract

Piezoelectric catalysis converts mechanical energy into chemical reactivity through electric fields generated by piezoelectric materials. Here, LiNbO₃ single crystals are employed as a model piezocatalyst to elucidate the microscopic mechanism of ultrasonic-driven catalysis. The atomically ordered lattice ensures structural stability and enables precise defect–field correlation. Under ultrasonic excitation, cavitation-induced stress produces transient polarization fields that drive redox reactions without external bias. ATR-FTIR spectra of methyl acrylate probe molecules reveal a carbonyl vibrational Stark shift, corresponding to an effective field of ~6.6 × 10⁷ V·m⁻¹. Experimental results demonstrate that single-crystal piezoelectric catalysts exhibit exceptional stability (>90% activity retention after 80 cycles), facile recovery due to their macroscopic monolithic morphology, and integrated device compatibility for scalable applications. These fields facilitate interfacial charge separation and generate •OH and •O₂⁻ radicals responsible for dye degradation. This work demonstrates that single-crystal LiNbO₃ enables efficient, recyclable, and stable piezocatalysis, and provides quantitative insight into the electromechanical–chemical coupling mechanism underlying ultrasonic piezocatalysis.