Adsorption-induced expansion of Graphene Oxide Frameworks: ob-servation by in situ neutron diffraction
Joseph C. Schaeperkoetter, Matthew J. Connolly, Haskell Taub, Helmut Kaiser, Carlos Wexler
We have investigated adsorption-induced deformation in graphene oxide frameworks (GOFs), using neutron diffraction. GOFs use a spacer molecule to create a slit-shaped pore defined by two adjacent parallel graphene-oxide (GO) sheets. They are an ideal candidate for deformation studies due to their narrow (∼1 nm), monodisperse, slit-shaped pores whose width can be meas- ured by diffraction. We have observed in situ a monotonic expansion of the slit width with in- creasing pressure upon adsorption of xenon at a temperature of 293 K, methane at 293 K, and hydrogen at 77 K at pressures up to 120 bar. The expansion of ∼4% observed for xenon at a pressure of 48 bar is the largest deformation observed for supercritical adsorption on a carbona-ceous material. We find that the expansion of the three gases can be mapped onto a common curve in a manner similar to a law of corresponding states, assuming the expansion is proportional to the number of adsorbate molecules, the adsorbate diameter squared, and the square root of the adsorbate's critical temperature. We conclude that the expansion observed is consistent with the spacer molecule interacting with the GO sheets via van der Waals forces rather than covalent bonds.
, Connolly, M.
, Taub, H.
, Kaiser, H.
and Wexler, C.
Adsorption-induced expansion of Graphene Oxide Frameworks: ob-servation by in situ neutron diffraction, ACS Ω, [online], https://doi.org/10.1021/acsomega.9b02589
(Accessed December 3, 2023)