Turning Color Confusion to Clarity: A Layered Ce−Based Nanozyme Drives Rapid Wavelength Transition for Discriminative Detection of Nerve Agent during Decontamination

Organophosphate (OP)‐based nerve agents (NAs) pose serious risks to human life, demanding materials that facilitate rapid decontamination and reliable detection with selectivity. Ce‐based metal organic frameworks (MOFs) are considered as promising candidates due to their high reactivity. However, their intrinsic yellow color misleads detection of NAs such as paraoxon, which releases yellow p ‐nitrophenol. Here, we report a bioinspired 2D metal‐organic layer (MOL) construct, Ce−BTB−MOL, a phosphotriesterase nanozyme with abundant binding sites that not only facilitate rapid degradation of paraoxon (t 1/2 = 6 min), but quick detection by a smart mechanism. This nanozyme seamlessly arrests product with its binding to Ce clusters and triggering wavelength transition that overcomes color confusion, enabling quick and confident detection within 13 s on paper strips. Mechanistic studies reveal that p ‐nitrophenol binding to Ce clusters induces ligand‐to‐metal charge transfer (LMCT), producing an intense orange‐brown signal. Based on the wavelength transition response, this nanozyme also showcases selective discrimination of structurally similar OPs, a challenge for conventional systems. Ce−BTB−MOL achieves real‐time, affordable, portable, easy, and rapid sensing without the requirement of sophisticated equipment, with a detection limit as low as 1.24 µg, quantifiable by smartphone RGB analysis. Importantly, the nanozyme demonstrates high selectivity against several interferents, allowing precise surface contamination analysis.