The selective detection of hydrogen sulfide (H2 S) is an important task because of its potentially hazardous effects not only on the environment but also on human health. Here, we present the zirconium-based MOF-808, which was modified with copper salts, as a colorimetric sensor material for the visible, reversible and sensitive H2 S detection at room temperature. The copper cations, which are incorporated in the oxidation state +II, are installed at the inorganic building units (IBUs) of the framework so that they are accessible for interactions with H2 S. The activated copper doped MOF-808 powder shows significant and fast color change in the presence of H2 S, which can be detected by UV-vis spectroscopy. Moreover, the detection process is reversible by heating the material to 120 °C under ambient conditions leading to its decolorization. The detection performance of the material was studied by in situ UV-vis measurements in a reaction chamber. The material was able to respond to 100 ppm H2 S in several cycles of exposure and heating to 120 °C under moist air conditions in a defined wavelength range. This reversibility is very uncommon for copper-based H2 S sensing reactions and highlights the potential of MOFs as selective sensing materials.
Keywords: colorimetric sensors; copper; gas sensors; hydrogen sulfide; metal-organic frameworks.
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