Room Temperature NO2 Sensing with a ZIF-67/rGO Nanocomposite: A Highly Sensitive Approach

Abstract

Nitrogen dioxide (NO₂) is a major atmospheric pollutant that poses a significant threat to human health, the development of efficient and accurate NO₂ gas sensors is crucial for air quality monitoring. Metal-organic frameworks (MOFs) are considered ideal materials for gas sensing due to their exceptional tunability, large surface area, high porosity, and abundant active metal sites. However, the poor conductivity of MOFs limits their applications in electrochemical sensors. This study presents a ZIF-67/rGO nanocomposite synthesized by combining reduced graphene oxide (rGO) with ZIF-67 via a one-step solution method. Experimental results demonstrate that the ZIF-67/rGO nanocomposite sensor shows significant sensitivity to NO₂ gas at room temperature. At 5 ppm NO₂, the response is approximately 13-fold higher than that of the pure rGO sensor. More importantly, the sensor achieves a detection limit as low as 0.5 ppm, with an ultra-fast response time of 15 s and recovery time of 40 s at room temperature. Additionally, the sensor exhibits excellent repeatability, long-term stability, and high selectivity for NO₂. This study presents an effective strategy for accurate real-time detection of low concentration NO₂ gas and provides valuable insights for designing MOF-based hybrid sensors at room temperature.