One-Dimensional MoS2-Decorated TiO2 nanotube gas sensors for efficient alcohol sensing

One-Dimensional (1D) MoS2-decorated TiO2 nanotubes were synthesized by the anodization of TiO2 nanotubes followed by a hydrothermal process for MoS2-decoration. The structure, morphology and surface characteristics of the MoS2-TiO2 composites were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and Brunauer-Emmett-Teller (BET). The results showed that TiO2 nanotubes can be filled and covered by flake-like MoS2 nanostructure. The numbers of the MoS2 layers ranged from 1 to 3. The TiO2 nanotube sensor shows a normal n-type response to reducing ethanol gas, whereas MoS2-TiO2 exhibits p-type response with excellent sensing performances. Specially, the sensitivity for the MoS2-TiO2 heterojunction increased almost 11 times than TiO2 nanotubes. This conversion of sensing behavior can be explained by the formation of p-n heterojunction structures.