Triple roles of Ag doping in MoS2 on piezoelectric polarization promoted peroxymonosulfate activation for wastewater pollutant degradation

Ag doping improves piezoelectric field and PMS/O 2 adsorption and activation. • The faster charge transfer of 2-Ag/MoS 2 boosts pollutant degradation activity. • PVDF membranes solve the recovery and reusability issues of powder catalysts. The integration of piezocatalysis with persulfate-based advanced oxidation processes holds substantial potential for pollutant remediation, yet its practical efficacy is often plagued by the limited piezoelectric field strength and low affinity of peroxymonosulfate (PMS). Herein, silver-doped layered molybdenum disulfide (Ag/MoS 2 ) was used to degrade pollutants by piezo-promoted PMS activation. The experimental results and theoretical calculations of adsorption energy, density of states (DOS) and electron localization function (ELF), clarified that Ag doping in MoS 2 plays a triple role in promoting the activation of piezoelectric driven PMS: Firstly, Ag doping can effectively improve the piezoelectric polarization field of the material. Secondly, it facilitates the adsorption and activation of oxygen-containing species such as PMS and O 2 by the catalyst. Thirdly, Ag acts as active sites and participates in the generation of reactive oxygen species (ROS). The synergistic effect promoted charge separation and reaction kinetics, significantly accelerating the activation of PMS and improving the degradation efficiency of ORZ. Furthermore, combined with the Fukui function calculations and liquid chromatography-mass spectrometry (LC-MS) measurements, the potential degradation pathways of ORZ during the reaction process were systematically revealed. Under ultrasonic (US) conditions, the piezoelectric catalytic degradation rate of ORZ (0.066 min −1 ) on the optimally Ag-doped MoS 2 was about 41 times higher than that of the sole PMS system and 5.5 times higher than that of bare MoS 2 . Furthermore, this catalyst enabled the efficient removal of various dye and antibiotic contaminants, including carbamazepine (CBZ), methylene blue (MB), and tetracycline (TC). Meanwhile, PVDF composite catalytic membranes were successfully fabricated in this study, which solved the critical problem of difficult recovery and reusability of powder catalysts. This new strategy can significantly enhance piezo-promoted PMS activation, providing important insights for the removal of pollutants.