Microporous Elastomer Filter Coated with Metal Organic Frameworks for Improved Selectivity and Stability of Metal Oxide Gas Sensors.

Despite various advantages and usefulness of semiconductor metal oxide gas sensors, low selectivity and humidity interference have limited their practical applications. In order to resolve these issues, we propose a new concept of a selective gas filtering structure that increases the gas selectivity and decreases the moisture interference of metal oxide gas sensors by coating metal organic frameworks (MOFs) on a microporous elastomer scaffold. Cu(BTC) with an excellent selective adsorption capacity for carbon monoxide (CO) compared to hydrogen (H2) and MIL-160 with an excellent moisture adsorption capacity were uniformly coated on the microporous polydimethylsiloxane (PDMS) structure through a squeeze coating method, resulting in a high content of MOFs with a large effective surface area. A Cu(BTC)-coated microporous PDMS filter showed an excellent adsorption efficiency (62.4%) for CO, thereby dramatically improving the selectivity of H2/CO by up to 2.6 times. In addition, an MIL-160 coated microporous PDMS filter showed a high moisture adsorption efficiency (76.2%).