High efficiently piezocatalysis degradation of tetracycline by few-layered MoS2/GDY: Mechanism and toxicity evaluation

A new strategy for the degradation of tetracycline in water by the piezo-catalysis of MoS2 doped with graphdiyne was proposed. The optimally doped MoS2/GDY-3 had a few and thin layer structure, and PFM characterization showed that the piezoelectric response of MoS2/GDY-3 was 35.29% higher than that of MoS2. MoS2/GDY-3 exhibited excellent catalytic activity, and the degradation rate of tetracycline reached 92.15% after 40 min by ball milling to trigger piezoelectric catalysis. After 5 cycles, the degradation rate reached 87.15%, which demonstrates the stability of the material. The influence of the MoS2/GDY-3 dosage, ball milling speed, TC concentration, pH, inorganic anions and water source on the degradation efficiency were investigated. ESR characterization showed that ∙OH and ∙O2– were the main active radicals of the piezoelectric catalysis. By analyzing the intermediate products, the possible degradation path of tetracycline was further analyzed, and a suitable mechanism of piezoelectric catalysis was proposed. The toxicity of intermediate products was evaluated to explore the toxicity changes in the degradation process. This work provides a new approach for changing the morphology of MoS2 to enhance its piezocatalytic performance and effectively degrade tetracycline in water.