An Ultra-Selective and Humidity-Resistant Room-Temperature-Operated NO Sensor Based on Black TiO.

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