Steam Etched Porous Graphene Oxide Network for Chemical Sensing

Abstract

Oxidative etching of graphene flakes was observed to initiate from edges and the occasional defect sites in the basal plane, leading to reduced lateral size and a small number of etch pits. In contrast, etching of highly defective graphene oxide and its reduced form resulted in rapid homogeneous fracturing of the sheets into smaller pieces. On the basis of these observations, a slow and more controllable etching route was designed to produce nanoporous reduced graphene oxide sheets by hydrothermal steaming at 200 °C. The degree of etching and the concomitant porosity can be conveniently tuned by etching time. In contrast to nonporous reduced graphene oxide annealed at the same temperature, the steamed nanoporous graphene oxide exhibited nearly 2 orders of magnitude increase in the sensitivity and improved recovery time when used as chemiresistor sensor platform for NO(2) detection. The results underscore the efficacy of the highly distributed nanoporous network in the low temperature steam etched GO.

Ultrafast viscous water flow through nanostrand-channelled graphene oxide membranes

“…2h,i). A second explanation is that due to the high porosity and the defects on the GO sheets [39][40][41] , the effective channel length in our system is much shorter than the theoretical value (B2 mm) calculated from LDx/h. Another possibility can be attributed to the enhanced water flow due to the ultralow friction and boundary slip in the nanoconfined hydrophobic channels formed between pristine graphene regions in the GO membranes 19 .…”

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.…”

Graphene Oxide as a Novel Nanoplatform for Direct Hybridization of Graphene-SnO2

“…[5][6][7] Despite those disadvantageous properties, however, GO has attracted increasing research interest owing to its unique properties including large surface area, high water solubility, facile processibility, and easy large-scale production. [8][9][10][11] In particular, the functional groups of GO may play an important role in facilitating molecular organization into functional hybrid nanocomposites.…”