Low-cost synthesis of nanocomposite of MoS2 and alkali-activated halloysite nanotubes for photocatalytic RhB degradation
In this work, a novel nanocomposite of highly-dispersed MoS2 nanosheets supported on alkali-activated halloysite nanotubes (a-HNTs) was fabricated via a simple hydrothermal method. The alkali (5 M NaOH herein) could attack the inert outer surface of HNTs and thus abundant surface defects were created, while the crystal structure and tube morphology of HNTs were still preserved. Electron microscopy also evidenced few MoS2 could grow on the outer surface of raw HNTs while they were uniformly assembled on the both outer surface and inner lumen of the a-HNTs. It suggested that both the defects at the outer surface and Al-OH at lumen could serve as the nucleation sites for the growth of MoS2 nanosheets. Furthermore, the as-prepared MoS2/a-HNTs nanocomposite exhibited significantly improved photocatalytic performance for rhodamine B (RhB) degradation compared with the MoS2/HNTs and pristine MoS2 microspheres, and photogenerated holes (h+) played more important role than hydroxyl radical (•OH) and superoxide radical (•O2-) during the photocatalysis, which was confirmed by radical trapping experiments. This work provides a low-cost fabrication of high-performance 2D materials by using modified natural mineral materials as a carrier.