Microwave-induced Assembly of CuS@MoS2 Core-shell Nanotubes and Study on Their Photocatalytic Fenton-like Reactions

CuS@MoS2 core-shell nanotubes were prepared by microwave-induced assembly techniques in the present work. Firstly, the Cu nanowires were vulcanized into hollow CuS nanotubes. Secondly, the sheet-shaped MoS2 were uniformly intercalated and assembled onto the surface of CuS nanotubes. The as-prepared CuS@MoS2 core-shell nanotubes were used in photocatalytic Fenton-like reaction system to remove high-concentration rhodamine B (RhB) in aqueous solution, which exhibited 100% degradation rate within 30 min under visible light (lambda>420 nm) irradiation. The morphology and structure of the as-obtained catalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectrometer (EDS) and X-ray diffractometry (XRD). UV-Vis absorption spectroscopy (UV-vis DRS) was used to characterize its basic optical properties. And to further learn the catalytic mechanism and make sure the active species of the photocatalytic Fenton-like reaction system, the heterojunction structure of the catalyst was analyzed and electron spin resonance (ESR) spectrum was carried to prove the existence of superoxide (O-2(-)) species. The high activity could be attributed to the unique multi-layer structure of CuS@MoS2, corresponding to the enhanced absorption and exciting ability of visible lights. Meanwhile, the heterojunction structure formed between MoS2 and CuS also promoted the transfer of photogenerated electrons, which could inhibit their recombination with photogenerated holes. More importantly, the cooperation mechanism formed between photocatalysis and Fenton-like reactions may exhibit strong promoting effect. The Cu2+ ions in CuS reacted with H2O2 to form a Fenton-like cycle, allowing the generation of reactive hydroxyl (.OH) species. While, the photogenerated electrons reacted with both the H2O2 and the molecular oxygen activated by MoS2 to produce .OH and .O-2(-) species. Both .OH and O-2(-) species worked together to oxidize pollutants rapidly. This work developed a recycled photocatalytic Fenton-like reaction system, which may offer new pathway for the treatment of environmental pollution.