Dual functionalized Co3O4 porous cages with Pd and Co-MOF for acetone gas sensing under high humidity

Abstract

Metal oxide semiconductor (MOS) gas sensors play a crucial role in gas sensors. However, the effect of higher ambient humidity on the sensitivity of MOS gas sensors is still largely an unsolved problem, limiting the application areas of sensors. In this work, an ultra-stable and sensitive acetone gas sensor based on dual functionalized Co3O4 porous cages with Pd and Co-MOF at high humidity is reported. The dual functionalized porous cages are made of MOF-derived Co3O4 porous cages substrate, Pd particles and hydrophobic Co-MOF coatings. The prepared porous cages composite exhibits humidity-independent and highly sensitive gas-sensing behavior to acetone under 70–90 % relative humidity (RH). The results indicate that the hydrophobic Co-MOF coatings not only offer excellent anti-humidity, but also show the ability of enrichment of low concentration acetone gas molecules, thus improving the sensitivity and response time of acetone detection. Meanwhile, due to the electronic spillover effect of Pd, porous cages composite possesses remarkable properties of high sensitivity, short response and recovery time, as well as low working temperature. The unique sensing characteristic makes the dual functionalized porous cages composite sensor a potential candidate for reliable noninvasive diagnosis of diabetes via exhaled breath analyses.