Bi vacancy-induced Bi2O2S nanosheets for remarkably boosting piezocatalytic degradation of dyes and antibiotic

• Bi-deficient Bi 2 O 2 S nanosheets were firstly constructed by a low-heating solid-state reduction method. • Bi vacancies can narrow bandgap and promote charge carrier separation of Bi 2 O 2 S. • Bi-deficient Bi 2 O 2 S nanosheets exhibited a universal piezocatalytic degrading activity under ultrasonic . Defect engineering is an efficient strategy to address piezoelectric-catalyzed degradation, but metal cation defects introduced in crystals have rarely been reported, owing to the formation of cationic defects requiring higher energy than that of anionic defects. Herein, Bi vacancy-induced Bi 2 O 2 S (BOS) nanosheets were synthesized for the piezoelectric-catalyzed degradation of organic dyes and antibiotic, utilizing a low-temperature solid-state reduction method with the help of NaBH 4 for the first time. Astonishingly, Bi 2 O 2 S (BOS-4) with a large number of Bi vacancies exhibited an impressive 95.69 % degradation rate for rhodamine B (RhB) under ultrasound, approximately three times higher than that achieved by BOS. Additionally, BOS-4 also effectively degrades other dyes as well. This phenomenon is mainly ascribed to reduced band gap and facilitated the generation of charges by the introduced Bi vacancies, which can attract negative charges move in a definite direction and promote effective charge separation, thereby improving piezocatalytic efficiency.