ABSTRACT
Carbon nanotubes (CNTs) and graphene hold a great promise for the development of miniaturized chemical sensors because of (1) greater adsorptive capacity due to large surface area to volume ratio, (2) better modulation of electrical properties (e.g., capacitance and resistance) upon exposure to analytes due to a greater interaction zone over the cross-sectional area, (3) ability to tune electrical properties of the nanostructure by adjusting the composition and size, and (4) the ease of con guration into different geometries. But these pristine forms of CNTs and graphene have drawbacks like lack of speci city to different gaseous analytes and the low sensitivity toward analytes that have no af nity to them. These limitations are reduced by functionalization of CNTs and graphene. Several research groups are currently working on the functionalization of CNTs and graphene with different materials to alter their chemical nature and enhance their sensing performance. Functionalization is an important aspect of the chemistry of CNTs and graphene and this chemical manipulation is essential for many of the potential applications like energy storage, energy conversion devices, sensors, hydrogen-storage media, nanometer-sized semiconductor devices, probes, and quantum wires. The development of CNTs and graphene-based sensors has attracted intensive interest in the last several years because of their outstanding sensing properties such as high selectivity and prompt response. In this chapter, an extensive overview of functionalized CNTs and graphene-based gas sensing is presented.
