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

Abstract

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.