Detection and discrimination of nitroaromatic vapors using a chemiresistive-potentiometric sensor based on dual-phase TiO2 nanowires/nanobelts

TiO 2 (B)/anatase dual-phase nanowires/nanobelts were synthesized. • A R-P bivariate sensor was developed for seven NAC vapors. • Enhanced R-P responses were achieved with dual-phase nanowires/nanobelts. • Distinct R-P response patterns enabled vapor discrimination. Nitroaromatic vapor detection and discrimination remain challenging because of the low vapor pressures and high structural similarity of these analytes under ambient conditions. Here, a chemiresistive-potentiometric (R-P) bivariate gas sensor based on TiO 2 (B)/anatase dual-phase nanowires/nanobelts was developed for the discrimination of seven nitroaromatic vapors, including 2,4,6-trinitrotoluene, 2,4-dinitrotoluene, 2,6-dinitrotoluene, p-nitrotoluene, m-nitrotoluene, o-nitrotoluene, and nitrobenzene. Compared with the reference sensor fabricated from commercial single-phase TiO 2 nanoparticles, the nanowires/nanobelts-based sensor exhibited substantially enhanced bivariate responses, with 6.5–31.1 times higher chemiresistive responses and 1.3–2.1 times larger potentiometric responses toward the seven vapors. The improved sensing performance is attributed to the synergistic effects of abundant oxygen vacancies, dual-phase interfaces, and porous nanowires/nanobelts morphology. In addition, the nanowires/nanobelts-based sensor generated well-distinguished R-P fingerprints. A handheld prototype integrating dual R-P channels was also constructed for portable nitroaromatic vapor analysis. This work provides an effective strategy for developing low-cost and portable platforms for nitroaromatic vapor detection and discrimination. Download: Download high-res image (193KB) Download: Download full-size image