High Sensitivity Gas Detection Using a Macroscopic Three-Dimensional Graphene Foam Network

Abstract

Nanostructures are known to be exquisitely sensitive to the chemical environment and offer ultra-high sensitivity for gas-sensing. However, the fabrication and operation of devices that use individual nanostructures for sensing is complex, expensive and suffers from poor reliability due to contamination and large variability from sample-to-sample. By contrast, conventional solid-state and conducting-polymer sensors offer excellent reliability but suffer from reduced sensitivity at room-temperature. Here we report a macro graphene foam-like three-dimensional network which combines the best of both worlds. The walls of the foam are comprised of few-layer graphene sheets resulting in high sensitivity; we demonstrate parts-per-million level detection of NH3 and NO2 in air at room-temperature. Further, the foam is a mechanically robust and flexible macro-scale network that is easy to contact (without Lithography) and can rival the durability and affordability of traditional sensors. Moreover, Joule-heating expels chemisorbed molecules from the foam's surface leading to fully-reversible and low-power operation.

A 3D Chemically Modified Graphene Hydrogel for Fast, Highly Sensitive, and Selective Gas Sensor

“…The adsorption of trace amounts of gas molecules on Gr surface causes significant charge transfer between Gr and gas molecules, resulting in a noticeable conductance change of Gr 5, 11. Since the pioneering work reported the capability of Gr to detect a single NO 2 molecule,12 Gr materials fabricated via various strategies, such as mechanical exfoliation,12, 13, 14 chemical vapor deposition,1, 9, 15, 16 epitaxial growth,17 and chemically18, 19, 20, 21 or thermally22 reduced graphene oxide (RGO) have been exploited for gas sensing. Among them, RGO has attracted widespread attention for this purpose due to the low cost and high yield in production, and the convenience of modifying it with functional groups or doping atoms to tailor its gas sensing properties 19, 23.…”

“…In addition to chemical modification of sensing materials, the performance of chemical sensors can also be enhanced through newly designed material structures. For example, recently 3D Gr/RGO porous structures have been utilized to significantly improve the gas sensing performance compared with the 2D counterparts 1, 4, 15, 28, 29. This is because the unique porous structure coupled with the inherent properties makes 3D RGO exhibit a higher surface area and much more “space” for the transportation or storage of electron/hole and gas, leading to an improved sensitivity 30…”

Biomimetic superelastic graphene-based cellular monoliths

“…A number of methods, such as self-gelation and chemical vapour deposition (CVD) over a porous catalyst have recently been developed to fabricate highly porous graphene cellular monoliths [5][6][7][8][9][10][11][12] . However, as with most of the existing porous carbon materials 13 , the resulting graphene monoliths are generally brittle and have small recoverable deformation before failure unless they are infiltrated with an elastomeric polymer 5 or grown on pre-formed carbon nanotube aerogels 14 .…”

Polyurethane foam coated with a multi-walled carbon nanotube/polyaniline nanocomposite for a skin-like stretchable array of multi-functional sensors

“…21 Thus porous foams coated with conductive nanomaterials can be used for fabrication of high-performance pressure, temperature and gas sensors owing to their combined advantages of electronic conductivity, mechanical flexibility and large specific surface area. 22 Here, for the first time, we demonstrate a skin-like stretchable array of MF sensors based on a single sensing material comprising polymer foam coated with MWCNT-PANI, which enables simultaneous detection of bio-signals such as skin temperature, wrist pulse and ammonia gas for health monitoring when attached to the skin. The pressure sensor shows a wide sensing range from 0.05 to 30 kPa, a fast response time of 20 ms, a high sensitivity of 2.1 kPa − 1 and high stability over 10 000 loading/unloading cycles.…”