Carbon nanotubes as electron mediators for CNTs/CdS/MoS2 high efficient photodegradation of tetracycline under visible light

The ternary nanocomposites of CNTs/CdS/MoS2 was synthesized by a simple two-step hydrothermal method and characterized accordingly. In situ growth of CdS on the surface of CNTs decreased the size of CdS particles and increased its dispersibility. Moreover, CdS took advantage of the good conductivity of CNTs to accelerate the conduction of photogenerated holes and reduced the recombination efficiency of charge carriers. MoS2 grew in situ on the surface of CdS, and the interface between them formed a close contact heterostructure. The built-in electric field formed at the interface between the two forced the photogenerated electrons of CdS and the holes of MoS2 to recombine here. This property not only changed the path of photogenerated electrons and holes, but also made the surface of MoS2 becoming the active center of reduction reaction. The hybrid structure of CNTs/CdS/MoS2 in-situ composite significantly improved the photocatalytic performance. When CNTs/CdS/MoS2 was used as photocatalyst, the degradation rate of tetracycline was 96.7% under 100 min of visible irradiation, and the data was still above 95% after 5 cycles indicate. This indicated that the ternary complex has good photocatalytic performance and stability. The successful preparation of CNTs/CdS/MoS2 provides an economically feasible approach for the degradation of tetracycline.