What is Gas Sensor

Gas sensing continues attracting research communities due to its potential applications in the sectors military, industrial and commercial. A special emphasis is placed on the use of carbon nanomaterials such as carbon nanotubes and graphene, as sensing materials. The chapter will be divided as follows: In the first part, a description of the main topologies and materials (carbon nanomaterials plus polymers, metals, ceramics or combinations between these groups) used to fabricate gas sensors based on graphene and carbon nanotubes that are operated by conductance or resistance electrical, is realized. Next, different mathematical models that can be used to simulate gas sensors based on these materials are presented. In the third part, the impact of the graphene and carbon nanotubes on gas sensors is exemplified with technical advances achieved until now. Finally, it is provided a prospective analysis on the role of the gas sensors based on carbon nanomaterials in the next decades.