1. Could you explain the significance of your article to the non-specialist?

Metal oxide-gas sensors are practical devices used in a variety of every-day applications, e.g. oxygen sensors in automobile exhausts or for detection of poisonous and/or explosive gases. The main technological advantage is their inexpensive fabrication; the down-side is the limited discrimination to different gases. To improve selectivity, a better fundamental understanding of the underlying atomic scale processes is desirable. This article reviews the recent advances made in increasing our knowledge of these processes for important metal oxide/gas phase interfaces. 

2. What has motivated you to conduct this work?  

Large efforts have been devoted by the surface science community to fields such heterogeneous catalysis; comparably very little work has been done on metal oxide gas sensing materials. Thus I saw a need to apply surface science methodologies to gain better fundamental understanding of metal oxide gas sensing materials. 

3. Where do you see this work developing in the future? 

Metal-oxide gas sensors have been around for over 40 years, but only now we have the tools available to investigate the basic atomic-scale processes. Key-questions, this research has been addressing and will in the future are the role of atomic scale defects on the gas sensing mechanisms and on how controlled defects (for example due to impurity atoms/ dopants) can be created to tune the gas sensitivity of these materials.

4. Are there any particular challenges facing future research in this area? 

Fundamental surface science studies of model systems under ultra high vacuum (UHV) conditions give us a great deal of detail of atomic scale processes. It will be necessary, though, to verify that the same processes are occurring under operating conditions. For this purpose more studies at the atomic scale under high pressure and high temperature conditions are necessary. Such studies combined with UHV experiments may be needed to single out the decisive processes from the multitude of processes occurring at these complex interfaces.