Highly selective and real-time Raman–QCM tandem detection of benzene from toluene based on a MOF–AgNW composite substrate

The selective separation and detection of benzene from toluene remains a critical challenge due to their structural similarity and the toxicity of benzene. In this work, we develop a novel composite substrate, PIZA-AgNW, consisting of a metal-organic framework (MOF), silver nanowires (AgNWs), and filter paper, fabricated via liquid-phase epitaxy (LPE). This substrate enables highly selective and real-time detection of benzene from toluene using tandem surface-enhanced Raman spectroscopy (SERS) and quartz crystal microbalance (QCM) analysis. The LPE method affords precise control of MOF thickness and pore structure, enhancing molecular selectivity for Raman detection. By correlating Raman intensity with QCM-derived mass changes, we achieve real-time monitoring of adsorption/desorption dynamics and quantify both equilibrium and nonequilibrium separation factors. Notably, a high equilibrium separation factor ( αₑ ) of 134 was obtained for a 1:1 benzene/toluene mixture. This work demonstrates a practical strategy for integrating structural selectivity with real-time sensing and offers broad potential for the dynamic monitoring of volatile organic compounds (VOCs) in environmental and industrial applications.