Enhanced NO₂ Sensing Performance of ZnO-SnO₂ Heterojunction Derived from Metal-Organic Frameworks

Nitrogen dioxide (NO₂) is the major reason for acid rain and respiratory illness in humans. Therefore, rapid, portable, and effective detection of NO₂ is essential. Herein, a novel and simple method to construct a ZnO-SnO₂ heterojunction is fabricated by pyrolysis of bimetallic metal organic frameworks. The sensitivity of ZnO-SnO₂ heterojunction towards 0.2 ppm NO₂ under 180 °C is 37, which is 3 times that of pure ZnO and SnO₂. The construction of heterojunction speeds up the response-recovery process, and this kind of material exhibits lower detection limit. The construction of heterojunction can significantly improve the NO₂ sensitivity. The selectivity, stability, and moisture resistance of ZnO-SnO₂ heterojunction are carried out. This could enable the realization of highly selective and sensitive portable detection of NO₂.