Rapid and Selective Fluorescent Sensing of Nerve Agent Simulants Using Copper‐Doped Lanthanide Metal‐Organic Frameworks

Nerve agents are lethal chemical warfare agents that pose severe threats to public health and national security. Herein, a luminescent terbium‐based metal–organic framework (Tb‐BTC) was synthesized via a facile and mild one‐step method, enabling rapid and convenient detection and adsorption of the nerve agent simulant diethyl chlorophosphate (DCP). The specific interaction between DCP and the MOF disrupts the antenna effect, resulting in fluorescence quenching. The introduction of 5% Cu into Tb‐BTC (Tb‐BTC‐Cu 0.05 ) significantly improves its selectivity, leading to an ultralow limit detection (LOD) of 0.13 µM, which is lower than most previously reported fluorescence‐based DCP sensors. Density functional theory (DFT) calculations indicate that partial substitution of surface Tb 3+ with Cu 2+ improves the adsorption affinity toward DCP. Tb‐BTC‐Cu 0.05 was immobilized on filter paper for vapor sensing, where the resulting fluorescence color change could be accurately quantified using a smartphone‐based application, providing a portable detection platform. The region of green fluorescence can be automatically identified and its average intensity extracted, allowing comparison with the background and initial intensity to determine the presence of DCP vapor. Overall, this work offers a promising strategy and material platform for further exploration of Ln‐MOFs in chemical warfare agent sensing.