Adsorption-Induced Expansion of Graphene Oxide Frameworks: Observation by in Situ Neutron Diffraction

Abstract

We have investigated adsorption-induced deformation in graphene oxide framework materials (GOFs) using neutron diffraction at sample pressures up to 140 bar. GOFs, made by the solvothermal reaction of graphite oxide and benzene-1,4-diboronic acid, are a suitable candidate for deformation studies due to their narrow (∼1 nm), monodispersed, slit-shaped pores whose width can be measured by diffraction techniques. We have observed, in situ, a monotonic expansion of the slit width with increasing pressure upon adsorption of xenon, methane, and hydrogen under supercritical conditions. The expansion of ∼4% observed for xenon at a pressure of 48 bar is the largest deformation yet reported for supercritical adsorption on a carbonaceous material. We find that the expansion of the three gases can be mapped onto a common curve based solely on their Lennard-Jones parameters, in a manner similar to a law of corresponding states.

Swelling properties of graphite oxides and graphene oxide multilayered materials

“…60 The same principle as in XRD can be used for the study of GtO and GO using neutron diffraction as demonstrated by several studies. [116][117][118] Summarizing this section, the diffraction method is a powerful instrument for studies of GO swelling but it has also some limitations. For example, it provides only the estimation of the inter-layer distance based on averaging over many layers, typically hundreds or thousands.…”

Adsorption-Induced Expansion of Graphene Oxide Frameworks with Covalently Bonded Benzene-1,4-diboronic Acid: Numerical Studies

“…In each simulation, the GOF structure (models i, ii, iv), GO, and DBA (model iii) were simulated fully atomistically, and the atoms were allowed to move with the exception of a fixed graphene bottom layer that simulates a solid graphite substrate, increases the stability of the simulation, and facilitates the analysis by keeping the structures roughly aligned parallel to the xy plane. This is a reasonable model since GOF samples have SSAs of ≈400 to 500 m 2 /g 18 compared to graphene’s theoretical surface area of 2600 m 2 /g.…”

“…In this paper, we focus on the structural properties of a type of GOF formed using an intercalation procedure originally proposed by Burress et al 9 and reproduced by Mercier et al 11 and Schaeperkoetter et al: 18 the dissolution of benzene-1,4-diboronic acid (DBA) in methanol and then intercalating the DBA into graphite oxide (GO), which lead to GOFs with SSA of ≈400 to 1000 m 2 /g and interlayer distances of ∼9 Å.…”

“…A significant breakthrough came in 2019 when Schaeperkoetter et al. 18 probed these structures by in situ neutron diffraction during supercritical adsorption of various gases at pressures in the 0–140 bar range. Thermal neutrons from the 10 MW University of Missouri Research Reactor were particularly well suited for structural investigations of GOFs 19 since they can readily penetrate the thick high-pressure aluminum sample cell (in contrast, X-ray scattering cross section increases with Z 2 , making it very difficult to probe carbon structures surrounded by thick metal walls).…”

Effects of long-term flue gas exposure on chemical-structural properties of South African coals: perspective on advanced analytical techniques

“…A similar relative comparison reported an increase of 37.5% and 17.3% in crystalline diameter for Coal EML and Coal SML, respectively. According to Schaeperkoetter et al (2019) this increase indicates successful incorporation of the gas molecules within the carbon crystals during the high-pressure adsorption process. The micrographs acquired from the FESEM of untreated and flue gas treated Coal EML and Coal SML are presented in Fig.…”