Application of Raman Spectroscopy to Working Gas Sensors: From <i>in situ</i> to <i>operando</i> Studies

• Main Authors: Ann-Kathrin Elger, Christian Hess
• Format: Article
• Language: English
• Published: MDPI AG 2019-11-01
• Series: Sensors
• Subjects: raman spectroscopy; gas sensors; metal-oxide (mox) gas sensors; operando spectroscopy; <i>in situ</i> spectroscopy; mechanism
• Online Access: https://www.mdpi.com/1424-8220/19/23/5075

Understanding the mode of operation of gas sensors is of great scientific and economic interest. A knowledge-based approach requires the development and application of spectroscopic tools to monitor the relevant surface and bulk processes under working conditions (<i>operando</i> approach). In this review we trace the development of vibrational Raman spectroscopy applied to metal-oxide gas sensors, starting from initial applications to very recent <i>operando</i> spectroscopic approaches. We highlight the potential of Raman spectroscopy for molecular-level characterization of metal-oxide gas sensors to reveal important mechanistic information, as well as its versatility regarding the design of in situ/operando cells and the combination with other techniques. We conclude with an outlook on potential future developments.