Decoupling Sensitivity and Recovery Kinetics of MOF/MWCNT-Based Gas Sensors Through Aerodynamic Chamber Design

This study investigates the aerodynamic trade-off between adsorption-driven sensitivity and desorption-driven recovery in MOF/MWCNT-based gas sensors. We compared two chamber designs: a Stable Flow Chamber (SFC) with streamlined laminar flow and a Disturbed Flow Chamber (DFC) featuring baffle-induced perturbations. Experimental results demonstrated that the SFC significantly enhanced sensitivity, showing increases of 16.3% (QCM), 21.1% (Resistive), and 53.8% (EIS) compared to the DFC, by promoting stable diffusion into the sensing layer. Conversely, the DFC markedly accelerated recovery kinetics, reducing recovery times by 10.3% (QCM), 12.3% (Resistive), and 55.9% (EIS), respectively, due to baffle-induced aerodynamic scrubbing. Computational fluid dynamics (CFD) confirmed that the DFC generates a 3.3 times higher wall shear stress even under a low Reynolds number regime (Re ≈ 2.3). These findings establish that aerodynamic design can effectively decouple sensitivity and recovery kinetics, offering a route to optimize sensor performance without modifying materials.