MOF-based colorimetric sensor for rapid and visual readout of trace acetylene

Amongst the rapidly growing metal-organic framework (MOF)-based sensors, a colorimetric MOF sensor for visual testing of analytes is highly desired but rarely reported. Here, we developed such a colorimetric sensor by crystallization of UiO-type crystals with thiomethyl pendants and postsynthetic installation of Pt. Thus-obtained UiO-68-SMe-Pt crystals display a remarkable color change upon exposure to C2H2 in various matrices, which can be identified by the naked eye within 15 s. As a result, the rapid visual detection of C2H2 with high sensitivity and selectivity is achieved. Its applicability was proved by visual readout of C2H2 in transformer oil, enabling convenient monitoring of the operation status of transformers in service. More importantly, we revealed that the color change of UiO-68-SMe-Pt arises from the Pt-driven C2H2 polymerization (MOF-analyte chemical reactivity), which is fundamentally different from the working principles of previous colorimetric MOF sensors.