A Sensitive “Optical Nose” for Detection of Volatile Organic Molecules Based on Au@MOFs Nanoparticle Arrays through Surface‐Enhanced Raman Scattering

Abstract Surface‐enhanced Raman scattering (SERS) is an effective technique for detecting toxic gas and volatile organic molecules (VOMs); however, recent SERS‐based gas sensors have disadvantages and lack an effective approach to capture toxic gas and insufficient reproducibility of SERS substrates. Herein, a facile strategy is developed to integrate metal‐organic frameworks with Au nanoparticle (NP) arrays to form Au@ZIF‐8 NP arrays, which can be used as an “optical nose” based on SERS to detect toxic VOMs with good reproducibility and sensitivity. Toluene as a target molecule is recognized at ppm levels by the Au@ZIF‐8 NP arrays in situ. And the analytical enhancement factor of Au@ZIF‐8 NP arrays for toluene is about 1.2 × 10⁵. Importantly, this SERS substrate can also detect the 1‐butanol molecule, which provides an idea for designing a universal VOM sensor. In addition, the coating method of the ZIF‐8 shell can be extended to synthetize various NPs@ZIF‐8 core–shell composites, such as Au nanospheres@ZIF‐8, Au@Ag nanorods@ZIF‐8, PS microspheres@ZIF‐8, and Fe₂O₃ microellipsoids@ZIF‐8 composites.