Fe/Mg co-doped MoS2 nanoflowers with synergistically enhanced piezo-Fenton performance for ultrasonic degradation of organic pollutants

Pristine MoS 2 shows promise for piezo-Fenton degradation of organic pollutants, yet its weak piezoelectric response and sluggish surface reaction kinetics severely limit catalytic efficiency. Herein, Fe/Mg co-doped MoS 2 nanoflowers were prepared by a one-step hydrothermal method, and the Fe/Mg ratio was adjusted to construct a catalyst with both piezoelectric response and Fenton activity. Among the samples, 5% Fe 3 Mg 1 -MoS 2 exhibited the best performance. Under ultrasound alone, it degraded 71.9% of tetracycline within 60 min, with an apparent rate constant of 0.0213 min −1 . In the ultrasound/H 2 O 2 system, the degradation efficiency increased to 97.8%, and the rate constant reached 0.0620 min −1 , about 4.0 times that of p-MoS 2 . Structural and surface chemical analyses showed that Mg enlarged the MoS 2 interlayer spacing, induced local lattice distortion, and promoted fewer-layer structures, providing favorable structural conditions for the piezoelectric response under ultrasound. Fe species provided Fe 3+ /Fe 2+ redox sites and promoted H 2 O 2 activation. Radical scavenging and fluorescence tests indicated that ·OH was the dominant reactive species in the ultrasound/H 2 O 2 system, while ·O 2 - and h + also participated in degradation. DFT calculations further showed that Mg neighboring Fe sites enhanced H 2 O 2 adsorption on Fe sites and regulated the local charge distribution. This study demonstrates that Fe/Mg co-doping improves the piezo-Fenton catalytic performance of MoS 2 through structural regulation and electronic coupling, offering guidance for efficient MoS 2 -based catalysts.