Metal-Organic-Framework Derived Co-Mo Multimetal Oxide Semiconductors: Selective Trace-Level Hydrogen Sulfide Detection.

The development of a highly selective and trace-level gas sensing platform for detecting hydrogen sulfide (H 2 S) remains a formidable challenge. To solve this problem, Co-Mo multimetal oxide semiconductors are rationally tailored by employing metal organic frameworks (MOFs) as self-sacrificial templates. The MOF-derived Co 3 O 4 /β-CoMoO 4 based gas sensors displays high sensitivity ( R g / R a = 22) to 10 ppm of H 2 S and ultralow limit of detection (10 ppb H 2 S). The formation of p-p heterojunction and multivalence states of Mo play a crucial role in electron transfer and oxygen adsorption. A sensor array constructed from four Co 3 O 4 /β-CoMoO 4 materials with different Co/Mo ratios demonstrates a superior selective discrimination of H 2 S from other VOCs and malodorous gases by principal component analysis (PCA). Besides, a H 2 S gas sensing and alarming platform was designed for monitoring the environment contaminated with H 2 S. This finding provides a feasible approach for the discovery of highly efficient gas sensors to monitor environmental H 2 S concentration.