Gas Discrimination and Concentration Prediction Based on Sensing Features Deriving from Molecular Interfacial Interactions

The chemresistive sensing process derives from the interfacial interactions between the gaseous molecule and the sensing material’s surface. However, the deeper understanding of gas-solid interfacial interactions during gas sensing is still a formidable challenge. In this study, we combine in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and in situ Raman spectroscopy to systemically investigate interfacial sensing reactions, adsorption-desorption processes of surface species and structural evolutions of cobalt oxide. Interestingly, we discover that the different electron densities of Co−O bonds are responsible for the changes in the sensor’s resistance among three kinds of target analytes, which reveals the origin of temperature/analyte-dependent sensing features. Furthermore, these features are utilized to enable sensors capable of discriminating volatile organic compounds and predicting gas concentrations by algorithm analysis. Our research provides molecular insights into the understanding of gas-solid interfacial interactions during the gas-sensing process and offers a valuable strategy for designing sensing materials with outstanding performance.