Ag aerogel/ZIF-8 nanocomposite as a sensitive and reproducible SERS platform for gaseous molecule detection

Noble metals and metal-organic frameworks (MOFs) composite serve as prospective substrate for surface-enhanced Raman scattering (SERS) technology. Herein, an Ag aerogel/ZIF-8 nanocomposite was synthesized and exploited as an ultrasensitive SERS substrate. The as-designed Ag aerogel/ZIF-8 nanocomposite exhibited superior SERS performance, enabling the detection of 4-mercaptobenzoic acid (4-MBA) probe molecules at an ultra-low concentration of 10^-10 M. The Ag aerogel/ZIF-8 nanocomposite demonstrated a remarkably high SERS enhancement factor (EF) of 3.73 × 10⁶. The SERS performance resulted from the combined contribution of electromagnetic field enhancement and charge-transfer process. Furthermore, the Ag aerogel/ZIF-8 nanocomposite exhibited good reproducibility, with the SERS signals showing minimal standard deviation in repeated measurements. The Ag aerogel/ZIF-8 nanocomposite further enabled SERS-based detection of gaseous benzaldehyde, demonstrating its potential for monitoring volatile organic compounds (VOCs) in air samples. Compared with conventional MOF- or aerogel-based SERS substrates, the as-prepared Ag aerogel/ZIF-8 nanocomposite combines excellent SERS activity with high porosity, large surface area, and strong adsorption ability. This unique hybrid structure significantly improves sensitivity, selectivity, and stability, showing high novelty and advancement for SERS detection, and can be applied to food safety, disease diagnosis and environmental monitoring.