Engineering morphology evolution of MOF-derived α-MoO3 towards triethylamine-sensing ability

Owing to the acidic surface and specific catalytic oxidation activity towards C-N bond, the α-MoO3 commonly exhibits a superior sensing response towards organic amine (eg. triethylamine). However, the challenge of sluggish recovery hinders the fast detection in actual demand. In this paper, distinct structural morphologies of the α-MoO3 (nanorods, nanoplates, and microsheets) have been reported through pyrolyzing the Mo-MOF nanorod precursor at varied temperatures in air. The surface structural information is evaluated using various characterization techniques. The result of gas-sensing experiment reveals the MOF-derived α-MoO3 nanoplate shows the optimum response towards triethylamine (TEA) vapor with the superior selectivity, high response (Ra/Rg=121.1–100 ppm), low practical detection limit (0.2 ppm), and approving response/recovery times (3/715 s) against the other MOF-derived α-MoO3 products. Furthermore, a surface interaction model between the TEA and lattice oxygen (OLatt) over the α-MoO3 surface is proposed to illustrate the improvement in sensing response. This paper demonstrates a reliable avenue of MOF-derived morphology engineering for optimizing the sensing capability.