Density Gradient Strategy for Preparation of Broken In 2 O 3 Microtubes with Remarkably Selective Detection of Triethylamine Vapor.

Tubule-like structured metal oxides, combined with macroscale pores onto their surfaces, can fast facilitate gas-accessible diffusion into the sensing channels, thus leading a promoted utilization ratio of sensing layers. However, it generally remains a challenge for developing a reliable approach to prepare them. Herein, this contribution describes a density gradient strategy for obtaining broken In2O3 microtubes from the In2O3 products prepared using a chemical conversion method. These In2O3 microtubes hold a diameter about 1.5 µm with many broken regions and massive ultra-fine nanopores onto their surfaces. When employed as a sensing element for detection of triethylamine (TEA) vapor, these broken In2O3 microtubes exhibited a significant response toward TEA from 1 to 100 ppm, and the lowest detection concentration can reach 0.1 ppm. In addition, an excellent selectivity of the sensor to TEA was also displayed, though exposed in other interfering gases, including ammonia, methanol, ethanol, isopropanol, acetone, and toluene. Such promoted sensing performances toward TEA vapor were ascribed to the broken configuration (superior gas permeability, high utilization ratio, 1D configuration with less agglomerations) and the low bond energy of C-N for TEA molecule.