Sensitive acetone detection at ppb levels using MIL-125(Ti) derived TiO2

The modulation of the crystal phase structure can change the band gap and chemisorbed oxygen content of the metal oxide semiconductors (MOSs) materials, thereby optimizing the gas sensing properties of the material. Herein, the effect of TiO2 with different crystal phase structures derived from MIL-125 (Ti) calcined at different temperatures on the gas-sensitive properties of acetone is investigated. The study indicates that despite anatase TiO2-400 (derived from MIL-125 (Ti) under calcination at 400 degrees C) having a large specific surface area and abundant oxygen vacancies, rutile TiO2-700 (derived from MIL-125 (Ti) under calcination at 700 degrees C) exhibits superior gas sensitive performance with the high sensitivity, good selectivity, fast response times, and an ultralow detection limit (200 ppb) for acetone (biomarker of diabetes). In-depth discussion shows that the excellent sensing performance can be attributed to the regulation of the crystal phase structure of TiO2 that is favorable for narrowing of band gap, the increase of chemisorbed oxygen content and adsorption energy of acetone molecules. In addition, TiO2-700 has excellent properties for diabetes detection in simulation. Our findings help to understand the effect of the crystal phase structure of the material on gas sensitive performance, paving the way for designing excellent TiO2-based gas sensors.