Flexible Metal–Organic Framework‐Based Mixed‐Matrix Membranes: A New Platform for H2S Sensors

Metal–organic framework (MOF)–polymer mixed‐matrix membranes (MMMs) have shown great potential and superior performance in gas separations. However, their sensing application has not been fully established yet. Herein, a rare example of using flexible MOF‐based MMMs as a fluorescent turn‐on sensor for the detection of hydrogen sulfide (H₂S) is reported. These MOF‐based MMMs are readily prepared by mixing a highly stable aluminum‐based nano‐MOF (Al‐MIL‐53‐NO₂) into poly(vinylidene fluoride) with high loadings up to 70%. Unlike the intrinsic fragility and poor processability of pure‐MOF membranes, these MMMs exhibit desirable flexibility and processability that are more suitable for practical sensing applications. The uniform distribution of Al‐MIL‐53‐NO₂ particles combined with the permanent pores of MOFs enable these MMMs to show good water permeation flux and consequently have a full contact between the analyte and MOFs. The developed MMM sensor (70% MOF loading) thus shows a highly remarkable detection selectivity and sensitivity for H₂S with an exceptionally low detection limit around 92.31 × 10^?9m , three orders of magnitude lower than the reported powder‐form MOFs. This work demonstrates that it is feasible to develop flexible luminescent MOF‐based MMMs as a novel platform for chemical sensing applications.