Energy‐Level Alignment at TiO2@NH2‐MIL‐125 Interface for High‐Performance Gas Sensing

• Published in: Angewandte Chemie International Edition Vol. 64; no. 7; pp. e202419195 - n/a
• Main Authors: Deng, Wei‐Hua, Zhang, Min‐Yi, Li, Chun‐Sen, Yao, Ming‐Shui, Xu, Gang
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 10.02.2025
• Edition: International ed. in English
• Subjects: electrical device; Energy bands; energy level alignment; Energy levels; Environmental monitoring; Gas sensors; Heterojunctions; high-performance NO2 detection; Metal oxides; Metal-organic frameworks; MO@MOF interface; Nitrogen dioxide; Optical properties; Room temperature; Sensors; Structural engineering; Titanium dioxide
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202419195

Metal oxide (MO)‐based chemiresistive sensors have great potential in environmental monitoring, security protection, and disease diagnosis. However, the thermally activated sensing mechanism in pristine MOs leads to high working temperature and poor selectivity, which are the main challenges impeding practical applications. Precise modulation of the band structure at the heterojunction interfaces of MOs offers the opportunity to unlock unique electrical and optical properties, enabling us to overcome these challenges. Metal–organic frameworks (MOFs) with tunable structures are promising materials for aligning the energy levels at the heterojunctions of MOs. Herein, we report the energy‐level structural engineering of MO@MOF heterojunctions to optimize chemiresistive sensing performance. The interface was flexibly modulated from a straddling gap to a staggered gap by ‐NH2 functionalization of TiO2@(NH2)x‐MIL‐125, varying x from 0 to 1 and 2, respectively. TiO2@(NH2)x‐MIL‐125 combines the advantages of MOs and MOFs to synergistically improve gas‐sensing properties. As a result, TiO2@NH2‐MIL‐125 is the first light‐activated material to detect NO2 at 1 ppb with a response time of < 0.3 min at room temperature. It also exhibited excellent selectivity and long‐term stability. Our study underscores the potential of energy band engineering in creating high‐performance sensors, offering a strategy to overcome current material limits. Metal oxide‐based chemiresistive sensors suffer from high operating temperatures and poor selectivity. The TiO2@(NH2)x‐MIL‐125 (x = 0, 1, or 2) heterojunctions enhance sensing performance through energy level modulation. TiO2@NH2‐MIL‐125 detects NO2 at 1 ppb in < 0.3 min at room temperature, exhibiting high selectivity and stability, thereby underscoring the role of energy band engineering in the advancement of sensor performance.