NAP-XPS Study of Ethanol Adsorption on TiO2 Surfaces and Its Impact on Microwave-Based Gas Sensors Response

Abstract

This work presents new elements of understanding for the microwave-based gas sensors behavior at room temperature. A TiO2-covered microstrip interdigital capacitor was submitted to various ethanol concentrations and showed a proportional response in the 1–10 GHz microwave range. For each concentration and right after ethanol injection, the sensor response presented a slight overshoot which is often found in gas sensors studies. Near ambient pressure photoemission experiments (NAP-XPS) were conducted to explore the physicochemical causes of this overshoot, and demonstrated the formation of an ethoxide during ethanol adsorption.

Keywords

• ethanol adsorption
• NAP-XPS
• microwave-gas sensors