As a new nanostructure, a graphene is a compound of carbon atoms with a two-dimensional structure that has attracted the attention of many nanoscale researchers due to its novel physical and chemical properties. The presence of all graphene atoms in the surface and its unique electrical properties, as well as the ability to functionalize and combine with another nanomaterial, has introduced graphene as a new and suitable candidate material for gas sensing. Over the years, many researchers have turned their attention to carbon nanomaterial. The unique optical, mechanical, and electronic properties of these nanostructures have led them to use these nanomaterials to develop tiny devices, such as low-consumption sensors. Carbon nanomaterial poses a threat to another nanomaterial in terms of their use in gas sensors. This review article discusses the use of carbon nanoparticles and graphene in gas sensors, examines the nodes in the commercialization pathway of these compounds, and presents the latest achievements. Finally, the perspectives of the challenges and opportunities in the field of sensors based on carbon nanomaterial and graphene are examined.

    Abstract
    1 Introduction
    2 Carbon nanomaterial
        2.1 Carbon black
        2.2 Carbon nanofibers
        2.3 Carbon nanotube
        2.4 Graphene
        2.5 Magnetron sputtering method of C-based nanostructured materials
    3 Gas sensors with carbon nanomaterial
        3.1 Carbon-black gas sensors
        3.2 Carbon nanofiber-based gas sensors
        3.3 Carbon nanotube-based gas sensors
    4 Methods of making grapheme
        4.1 Mechanical delamination method
        4.2 CVD chemical vapor deposition method
        4.3 Chemical method
        4.4 Graphene-based sensors
    5 Gas sensors based on graphene oxide-metal two-component structures
    6 Gas sensors based on graphene oxide-metal oxide two-component structures
    7 Conclusion and perspective
    Acknowledgements 
    References

• Indah Raya(Chemistry Department, Faculty Mathematics and Natural Science, Hasanuddin University)
• Hamzah H. Kzar(Department of Chemistry, College of Veterinary Medicine, Al-Qasim Green University)
• Zaid Hameed Mahmoud(Chemistry Department, College of Science, Diyala University)
• Alim Al Ayub Ahmed(School of Accounting, Jiujiang University)
• Aygul Z. Ibatova(Tyumen Industrial University)
• Ehsan Kianfar(Department of Chemical Engineering, Arak Branch, Islamic Azad University, Young Researchers and Elite Club, Gachsaran Branch, Islamic Azad University)