Metal-Organic Framework-Assisted Construction of TiO2/Co3O4 Highly Ordered Necklace-like Heterostructures for Enhanced Ethanol Vapor Sensing Performance.

In this work, we report a metal-organic framework (MOF)-assisted strategy to synthesize necklace-like TiO2/Co3O4 nanofibers with highly ordered heterostructures via a facile approach including electrospinning and subsequent calcination. Polycrystalline TiO2 nanofibers and Co3O4 nanocages are consummately interconnected to form a highly ordered heterogeneous nanostructure, which can be of benefit for precisely accommodating the interface resistance of the p-n heterojunctions and the future realization of improved material performance. The ethanol-gas-sensing investigation showed that TiO2/Co3O4 nanofiber sensors exhibited a strong ethanol response ( Rair/ Rgas -1 = 16.7 @ 150 ppm) and a low operating temperature of 150 °C. The sensing enhancement mechanism of the TiO2/Co3O4 nanofibers is related to the formation of heterojunctions at interfaces and the high catalytic activity of MOF-derived Co3O4. Furthermore, this versatile method is a promising approach to constructing ordered heterostructures and extending the MOF-based heterogeneous materials toward wide applications.