Persulfate activation of CuS@Ti3C2-based MXene with Bi-active centers toward Orange II removal under visible light

The Ti3C2-based MXene with unique lamellar nanostructure and high conductivity is expected to effectively improve photocatalytic ability of composites as a cocatalyst. Herein, two dimensional Ti3C2-based MXene nanosheets decorated with copper sulfide particles (CuS@MXene) were synthesized by hydrothermal treatment to boost catalytic persulfate (PS) activation under light, exhibiting remarkable reactivity and stability for the rapid removal of Orange II. The phase composition of CuS@MXene was detected by X-ray diffraction (XRD), the morphology of CuS@MXene was characterized by scanning electron microscope (SEM), and the results of X-ray photoelectron spectroscopy (XPS) proved the elemental composition and valence state of elements in the CuS@MXene. The dosage of PS and initial pH of solution were the main factors affecting the removal rate of Orange II, and the quenching experiment showed that 1O2 was the primary reactive species for the removal of Orange II in CuS@MXene -PS system. In addition, this study showed that CuS@MXene provided bi-active centers for PS activation, which was mainly attributed to the rapid charge transfer between dual electron-rich active centers of Cu and Ti. This system may be applicable to the degradation of other challenging organic pollutants.