Work

An Ultra‐Selective and Humidity‐Resistant Room‐Temperature‐Operated NO 2 Sensor Based on Black TiO 2

Year: 2025

Type: article

Abstract: As a common gas‐sensing material, TiO 2 is limited by poor gas selectivity and humidity immunity like many other metal oxides. Here, an ultra‐selective and humidity‐resistant room temperature‐operated NO 2 sensor is developed using black TiO 2 for the first time. Compared with conventional white TiO 2 , black TiO 2 significantly enhances NO 2 selectivity and humidity resistance by enhancing the NO 2 response for ≥10 times while simultaneously suppressing responses to 7 common interfering gases and H 2 O adsorption. A wireless portable equipment is developed that exhibits the capabilities of identifying NO 2 from a mixed atmosphere and recognizing environmental differences in practical scenarios. These improvements and different response types are attributed to the regulation of H 2 O adsorption: H 2 O layers are formed on white TiO 2 , leading to dominant ion‐proton conductivity and blocked gas–solid interactions, while H 2 O adsorption is suppressed and hydroxyl groups are formed on black TiO 2 , enhancing NO 2 response. This study not only promotes a significant advancement and proves the feasibility of using common metal oxides for high‐performance NO 2 detection at room temperature in a mixed environment irrespective of ambient humidity, but also offers valuable insights into the sensing mechanisms.

Source: Advanced Science

DOI: 10.1002/advs.202509293