The novel sensors based on TiO₂ nanotubes-supported MS (TiO₂@MS, M = Cd, Zn) are synthesized via a simple wet chemical method at room temperature. The products are characterized with transmission electron microscopy (TEM), X-ray diffraction (XRD), and photoluminescence spectrum (PL). Their optical and morphological properties indicate the interaction between the TiO₂ nanotube and MS nanoparticle. The gas-sensing properties of the obtained samples are studied. Sensors based on the TiO₂@MS core/shell heterostructures all show improved gas-sensing properties. The results reveal that the improved performance of the nanocomposites strongly depends on the specific interaction between MS and support.

Ion-exchangable trititanate nanotubes synthesized by the alkali treatment of TiO₂ (anatase) are modified by MS (M = Cd, Zn) nanoparticles via a simple wet chemical process. The obtained samples are characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy. The photocatalytic activities of the samples are evaluated upon the oxidation of methyl orange under UV light illumination. Results show that the photoactivation may be caused by the strong coupling between the nanotube and the nanoparticles, which is a direct consequence of the ion exchange property of the trititanate wall structure during the formation of TiO₂/MS.