Low-Cost and High-Stable C-SiO2-PTFE Gas Diffusion Membrane for Ultrafast Electrochemical NO2 Sensor

Abstract

Electrochemical gas sensors (EGSs) are the most effective means for detecting NO₂ gas in industry, while facing the issue of exorbitant cost due to the use of expensive Pt catalyst. Herein, well-dispersed C-SiO₂ into polytetrafluoroethylene (PTFE) was adopt as high-stable gas diffusion membrane for ultrafast electrochemical NO₂ sensors. The nano-SiO₂ not only prevents material aggregation but also constructs porous networks between the gas diffusion electrode and gas molecules, providing a larger sensing area for high sensor performance. The fabricated sensor exbibits excellent response linearity, short response time, and high stability. As compared with commercial Pt/C electrode, the sensor response is improved by 170%. Moreover, a multiple linear regression model was introduced to predict the response values of NO₂ in the range of 5-100 ppm, achieving only 1.5% deviation from the real values. This work not only demonstrates the feasibility of non-precious metals in gas diffusion membranes but also provides guide for designing next-generation low-cost EGSs.