Two Low-Dimensional MOFs: Promising Sensors for Selective and Sensitive Detection of Nitroaromatic Compounds in Aqueous and Vapor Phases

Nitroaromatic compounds (NACs) are widely used in industrial production and daily life, posing significant hazards to both the ecological environment and human health. However, the development of efficient and user-friendly sensors still faces substantial challenges. In this study, we successfully designed and constructed two types of low-dimensional metal-organic frameworks (MOFs). By leveraging their unique properties, including high surface activity, rapid diffusion, and excellent dispersibility, we have effectively addressed the core issues in NACs detection─insufficient sensitivity, slow response, and low selectivity. These MOF-based materials demonstrate dual capabilities: Among them, Zn-TCPE-bpy exhibits superior detection performance toward 4-NA, with a Ksv value of 1.3 × 105 M-1 and a limit of detection (LOD) of 0.63 μM. Moreover, it exhibits a rapid response (<10 s) toward ppb-level 4-NA vapor. Through comprehensive experimental analysis verified by DFT calculations, we have demonstrated that the fluorescence detection mechanism involves a synergistic effect combining competitive absorption with photoinduced electron transfer. Furthermore, test paper fabricated through simple loading procedures has shown significant potential for practical applications across various scenarios. This work provides novel research insights and practical approaches for MOF-based NACs detection technologies.