Metal-organic frameworks-derived hollow Co3O4 nanotubes for efficient detection of toluene vapor

Low chemical reactivity of toluene remains a limiting factor for its efficient detection. Catalytic oxides (eg. Co3O4)-based sensors always exhibit reliable selectivity towards toluene vapor owing to the specific catalytic oxidation activity. However, the sensor response (especially the actual detection limit) still requires for further improving in a harsh ambience. In this paper, a metal-organic framework (MOF)-derived hollow Co3O4 nanotubes has been demonstrated using a sacrificial template (MoO3 nanorods) method. Benefiting from the efficient surface and internal spaces for gas diffusion and gas-solid interaction, this hollow nanotubular Co3O4-based gas sensor declares a low actual detection limit (∼1 ppm), favorable selectivity, and reliable stability towards toluene gas at 200 °C. Moreover, the sensor responses slightly reduce as the increased ambient humidity under a wide range (25–95 %), indicating a suitable feature of anti-humidity response. This work sheds the rationally designing catalytic oxides for detecting low reactive gas molecules (eg. toluene).