Temperature modulated Cu-MOF based gas sensor with dual selectivity to acetone and NO2 at low operating temperatures

Acetone and NO2 are gaseous species harmful to the human body even at very low concentrations. Thus, highly sensitive and selective sensors for both the gases are required for biomedical and environmental sectors. Here, we report on the use of metal-organic frameworks (Cu-MOF)-based conductometric sensors for the simple sensing of these gases. Copper linked benzene-1,2,4,5-tetracarboxylate metal-organic frameworks (Cu-MOF) was synthesized by hydrothermal method and its detailed morphological and structural properties have been investigated by XRD, TG-DTA, FE-SEM, HR-TEM and EDS studies. Gas sensing devices were fabricated by printing thick film of Cu-MOF powder on conductometric ceramic platform provided with Pt interdigitated electrode and integrated heater. On the basis of physical characterization and in-situ electrical studies, two sensors have been fabricated using Cu-MOFs heat treated at 250 °C and 400 °C in air, and named as Cu-MOF250 and Cu-MOF400, respectively. The Cu-MOF400 based electrodes exhibit promising sensing ability towards the detection of acetone at operating temperature of 250 °C, whereas Cu-MOF250 has the better sensing ability towards NO2 gas at 40 °C. It has been successfully demonstrated that the Cu-MOF250 sensor has dual sensing capability, able to detect selectively acetone at the operating temperature of 200 °C, and NO2 at near ambient temperature (40 °C).