A Synergistic Enhancement Architecture Based on Porous MoOx Nanobowls for Ultrasensitive and Selective SERS Detection of Gaseous Aldehydes

The application of surface-enhanced Raman spectroscopy (SERS) into gas sensing, particularly for breath-based diagnostics, is hindered by the challenge of simultaneously achieving high sensitivity, selectivity, and stability. This work introduces a synergistic enhancementarchitecture based on porous molybdenum oxide (MoO x ) nanobowl arrays to overcome this trilemma. This architecture is designed to couple electromagnetic field enhancement, efficient gas adsorption/concentration, and specific molecular recognition within a single unit cell. Finite element simulations confirm that the concave geometry creates densely packed electromagnetic hotspots, while the mesoporous structure induces gas vortices that prolong analyte residence time precisely within these enhancement zones. Functionalized with 4-aminothiophenol (4-ATP), the substrate achieves a detection limit of 0.95 ppb for 4-ethylbenzaldehyde (EBA), maintains high selectivity in complex simulated breath matrices, and exhibits remarkable long-term stability. This study proposes a potential design principle for next-generation, non-metal SERS platforms, supporting their potential in non-invasive early disease diagnosis.