Ti-MIL-125-Induced Tubular In2O3/TiO2 Heterostructures with Ultra-Sensitivity for Detecting N-Pentanol at Room Temperature

Recently, the development of an n-pentane-sensing product has always been plagued by the lack of suitable inorganic material with good gas-sensing response and selectivity at low operating temperatures. In this work, Ti-MIL-125-induced one-dimensional tubular In 2 O 3 /TiO 2 heterostructures have been fabricated by a facile electrospinning method and a subsequent heat-treatment process. Obvious morphological evolution from a fibrous to a tubular shape with the presence of In 2 O 3 -TiO 2 heterojunctions can be adjusted by varying the added amount of the Ti-ML-125 component. Compared with pure In 2 O 3 , the optimal In 2 O 3 /TiO 2 composites exhibit a blue-shifted energy band (2.52 eV) and an increased specific surface area (227.70 m 2 /g), as well as the enhanced gas-sensing performance on various concentrations of n-pentane. For example, In 2 O 3 /TiO 2 -3% can not only display excellent long-term stability and humidity stability but also has a high response of 670–100 ppm n-pentanol at 50°C, much larger than that of pure In 2 O 3 (50) at 150°C. Significantly, In 2 O 3 /TiO 2 -3% can still reach the high response of 197–100 ppm n-pentanol at room temperature. According to density functional theory (DFT) calculations, the enhanced gas-sensing mechanism is mainly attributed to the combination of the distinctly increased surface active sites through the regulation of morphology and the introduction of effective In 2 O 3 -TiO 2 heterojunctions, which can be beneficial to improving the surface adsorption/desorption characteristics and the electron transport between n-pentanol and the sensing material interface. Graphical