Separable Magnetic Fe3O4@MoS2 Composite for Adsorption and Piezo-Catalytic Degradation of Dye

Abstract

Well-designed composite catalysts are of increasing concern due to their improved performance compared to individual components. Herein, we designed and synthesized an Fe3O4@MoS2 composite via a simple hydrothermal method. As for the resultant composite, the MoS2 nanolayers presented a novel piezo-catalytic effect, while the Fe3O4 core provided a magnetic separation property. The structure and properties of Fe3O4@MoS2 were determined by relevant experiments. It was found that Fe3O4@MoS2 exhibited enhanced piezo-catalytic degradation of rhodamine B and good magnetic recovery/recycling features. The kobs for rhodamine B degradation over Fe3O4@MoS2 was 0.019 min−1—a little longer than that over MoS2 (0.013 min−1). Moreover, Fe3O4@MoS2 also showed a favorable ability to adsorb rhodamine B in solution, with a saturation adsorption of 26.8 mg/g. Further studies revealed that piezo-electrons, holes, and superoxide anions were key species in the piezo-catalytic degradation of rhodamine B. Notably, the step where oxygen trapped electrons to produce superoxide anions had a significant impact on the degradation of the dye. This work, not limited to the development of a high-performance MoS2-based piezo-catalyst, is expected to provide new insights into the working mechanisms and process profiles of composite piezo-catalysts.