CO₂ sensing under ambient conditions using metal-organic frameworks

Determining accurately CO₂ levels is highly relevant when monitoring indoor air quality. Nondispersive infrared (NDIR) sensors are the most often used sensors for measuring carbon dioxide concentration. However, the complexity of the device, power consumption and scalability are the main drawbacks associated with the state-of-the-art devices. In this work, we discuss the application of metal–organic frameworks for sensing of CO₂ molecules using electrochemical impedance spectroscopy. Impedance CO₂ sensors were fabricated using two metal–organic frameworks known for their selective CO₂ adsorption capability as well as their high proton conductivity, namely Zn-MOF-74 and NdMo-MOF. Both sensors showed a significant change in impedance when changing the CO₂ concentration and the relative humidity. Notably, the Zn-MOF-74 impedance sensor showed fast response when changing the humidity and CO₂ concentration.