Structural response of a slit-shaped graphene nanopore to adsorption: Observation by in situ neutron diffraction*

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 solvothermal reaction of graphite oxide (GO) and benzene-1,4- diboronic acid (DBA), 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 [1]. 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. All scattering measurements were performed on the 2-axis powder diffractometer at the Missouri University Research Reactor (MURR).
[1]. Schaeperkoetter, J. C. et al. Adsorption-Induced Expansion of Graphene Oxide Frameworks: Observation by in Situ Neutron Diffraction. ACS Omega (2019) doi:10.1021/acsomega.9b02589.