Study of water adsorption on graphene edges

Abstract

Water adsorption on graphene edges was studied by field emission (FE) experiments and first principles simulation.

A few-layer graphene for advanced composite PVDF membranes dedicated to water desalination: a comparative study

“…This behaviour is in agreement with what recently observed for GPNs (UW) 35 and suggested there was no inertia of graphene towards water vapour but rather a supporting action in the diffusion process. This experimental evidence is unquestionably corroborated by the literature, which refers to a certain aptitude of graphene to interact with water molecules [42][43][44][45]72 with indications from the adsorption of water vapour on exfoliated GPNs of up to 249 cm 3 g À1 at 20 C, 42 the adsorption of water on the edge of graphene through the dissociation of H 2 O to an H atom and OH group, 71 the increased work adhesion between water and the membrane surface modied with GPNs. 45 Herein, Raman spectroscopy gave an indication of the presence of defects due to the edges of the WJM akes (Fig.…”

Origin of the catalytic activity at graphite electrodes in vanadium flow batteries

“…The major part consists of hydroxyl groups formed at basal planes, whereas carbonyls and carboxylic groups develop at edge sites. 34,81,82 This is consistent with the decrease of the D-parameter (from 19 to 17, Figure 6b), which we ascribe mostly to the formation of oxygen groups at edges or defects of the sp 2 planes, resulting in sp 3 carbon-oxygen bonds. The higher amount of oxygen is also observed in the increased σ(C-O) signal of the O 2s region in the valence band spectra (Figure S13).…”

Cross‐sectional structural characterization of the surface of exfoliated HOPG using HRTEM‐EELS

“…It has been reported that the surface of HOPG cleaved using adhesive tape presented steps, and the edges of the steps were formed by graphene layers that broke during peeling; 17 moreover, the formed step edges of the graphene layers that reacted with atmospheric oxygen and oxygenated carbon species were produced 17 . Furthermore, the quantum mechanics/molecular mechanics and density functional theory approaches confirmed the formation of CH, COH, and CO bonds via the reaction of the graphene edges with water molecules 29,30 …”

“…17 Furthermore, the quantum mechanics/molecular mechanics and density functional theory approaches confirmed the formation of C H, C OH, and C O bonds via the reaction of the graphene edges with water molecules. 29,30 Hence, using the above-mentioned EELS analysis results and literature-reported data, it was suggested that the adhesive tapeexfoliated HOPG presented a roughened surface with disordered graphene layers which reacted with atmospheric oxygen and water molecules. It is of great importance that the difference in the surface and internal structure of HOPG including the chemical bond can be clarified at the atomic level through the HRTEM observation combined with the STEM-EELS measurement by using the crosssectioned HOPG sample.…”