Hamed Sadeghi - ۱. Graduated with a master's degree in chemical engineering from Islamic Azad University, Qochan Branch, Iran

This paper presents the fundamental work done on the design and development of different types of gas sensors using carbon nanotubes. The basic techniques for preparing carbon nanotubes are also reported here. Types of sensors and their detection processes in a wide range of gases including NO۲, H۲S, C۲H۵OH, and others are described here. Single-walled and multi-walled carbon nanotubes in their pristine andcombined form have been used to develop a wide range of measuring devices. It also provides a comparative ftstudyfeach gasthatprovides basicparameters such asdetection limit, concentration range, and response time to differentiate their ability with respect to the materials used for their manufacture to detect gases. to give Finally, the challenges related to existing carbon nanotube-based gas sensors, their related improvement measures, and some possible opportunities for future work are described in this paper.

Carbon nanotubes, Gas sensors, Chemical sensors, Functional CNTs