Defect-rich MoS2 piezocatalyst: Efficient boosting piezocatalytic activation of PMS activity towards degradation organic pollutant

Piezocatalytic technology opens a new avenue in driving green catalysis processes by harvesting mechanical energy, but the catalytic activity is still far from satisfying. In this work, defect-rich molybdenum disulfide (DR-MoS2) piezocatalyst was prepared and explored piezocatalytic activation peroxymonosulfate (PMS) performance towards degradation of organic pollutant (RhB dye) under ultrasonic vibration (US) condition. DR-MoS2/PMS/US system exhibits an excellent catalytic activity such as high degradation efficiency (∼92.1% after 25 min), large kinetic rate constant (0.09533 min−1) as well as good stability, far surpassing most of the reported other piezocatalyst systems. Particularly, degradation kinetic rate constant of DR-MoS2/PMS/US system is over 13 and 3 times than that of single normal MoS2 values under US and US/PMS conditions, respectively. The outstanding catalytic activity in DR-MoS2/PMS/US system is mainly ascribed to the strong synergistic effect between piezocatalysis and PMS as well as electrochemical reaction in catalytic process. More importantly, hydroxyl radicals (·OH), sulfate radicals (SO4˙−) and superoxide radicals (·O2−) are primary reactive oxygen species in piezocatalytic activation PMS process towards RhB degradation. Furthermore, we further clarify the possible piezocatalytic mechanism in DR-MoS2/PMS/US system towards RhB degradation. This work not only extends the application of piezocatalysis, but also offers beneficial guidance towards high-efficiency mechanically activated persulfate in sustainable wastewater remediation.