The
electrical conductivity of carbon nanotubes (CNTs) has been
demonstrated to be highly sensitive to the change of vapor/gas molecules
in the local environment owing to the large specific surface area
and quantum size effect, which enable CNTs to be an ideal sensing
material for next-generation room-temperature gas sensors. However,
the sensing properties of CNT films or networks cannot be maximized
because of the inevitable agglomeration during the fabrication process.
Herein, three-dimensional (3D) SiO2@multiwalled CNTs (MWCNTs)
core–shell nanospheres have been first used to fabricate room-temperature
gas sensors, which were prepared using an electrostatic self-assembly
method. The as-fabricated 3D SiO2@MWCNTs sensor exhibits
a recorded sensitivity of 82.61% toward 1 ppm nitrogen dioxide (NO2) at room temperature, which is 1.97 times higher than that
of devices based on random two-dimensional (2D) MWCNTs. Meanwhile,
the recovery time of ∼44 s is smaller than that of a 2D MWCNT
gas sensor. Such an ultrahigh sensing performance is attributed to
an effective utilization of the large specific surface area of MWCNT
networks with 3D structures. We believe that our findings will contribute
to the further development of high-performance CNT-based sensing devices
and also provide a new approach to fabricate the sensing devices using
one-dimensional nanomaterials.
Reduced graphene oxide (rGO) is considered as one of the ideal sensing materials for high-performance roomtemperature gas sensors owing to its large specific surface areas, numerous active sites, and high carrier mobility. However, the sensing performance cannot be maximized due to the inevitable sheet stacking and agglomeration. Herein, we firstdemonstrate multichannel room-temperature gas sensors using magnetic-fieldinduced alignment of three-dimensional (3D) Fe 3 O 4 @SiO 2 @rGO core−shell spheres. Moreover, the sensing channels composed of spheres can be tailored by changing the concentration of spheres and the magnetic field. Experimental results suggest that the multichannel 3D Fe 3 O 4 @SiO 2 @rGO sensor exhibits an ultrahigh sensitivity of 34.41 with a good response stability and high selectivity toward 5 ppm of NO 2 at room temperature, which is ca. 7.96 times higher than that of the random 3D rGO gas sensor. The high performance can be mainly ascribed to a full utilization of their large specific surface area and active sites of rGO nanosheets. We believe that our results not only contribute to the development of high-performance rGO-based sensing devices, but also provide a general approach to maximize the sensing performance of other nanomaterials.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.