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 (H₂S) 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 Co₃O₄/β-CoMoO₄ based gas sensors displays high sensitivity (R_g/R_a = 22) to 10 ppm of H₂S and ultralow limit of detection (10 ppb H₂S). 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 Co₃O₄/β-CoMoO₄ materials with different Co/Mo ratios demonstrates a superior selective discrimination of H₂S from other VOCs and malodorous gases by principal component analysis (PCA). Besides, a H₂S gas sensing and alarming platform was designed for monitoring the environment contaminated with H₂S. This finding provides a feasible approach for the discovery of highly efficient gas sensors to monitor environmental H₂S concentration.