Assembly of ZIF‐67 Metal–Organic Framework over Tin Oxide Nanoparticles for Synergistic Chemiresistive CO₂ Gas Sensing

Metal–organic frameworks (MOFs) are widely known for their record storage capacities of small gas molecules (H 2 , CO 2 , and CH 4 ). Assembly of such porous materials onto well‐known chemiresistive gas sensing elements such as SnO 2 could be an attractive prospect to achieve novel sensing properties as this affects the surface chemistry of SnO 2 . Cobalt‐imidazole based ZIF‐67 MOF was grown onto preformed SnO 2 nanoparticles to realize core–shell like architecture and explored for greenhouse gas CO 2 sensing. CO 2 sensing over SnO 2 is a challenge because its interaction with SnO 2 surface is minimal. The ZIF‐67 coating over SnO 2 improved the response of SnO 2 up to 12‐fold (for 50 % CO 2 ). The SnO 2 @ZIF‐67 also showed a response of 16.5±2.1 % for 5000 ppm CO 2 (threshold limit value (TLV)) at 205 °C, one of the best values reported for a SnO 2 ‐based sensor. The observed novel CO 2 sensing characteristics are assigned to electronic structure changes at the interface of ZIF‐67 and SnO 2 .