Pore wall corrugation effect on the dynamics of adsorbed H2 studied by in situ quasi-elastic neutron scattering: Observation of two timescaled diffusion.
- Resource Type
- Article
- Authors
- Koppel, Miriam; Palm, Rasmus; Härmas, Riinu; Russina, Margarita; Grzimek, Veronika; Jagiello, Jacek; Paalo, Maarja; Kurig, Heisi; Månsson, Martin; Oll, Ove; Lust, Enn
- Source
- Carbon. Sep2022, Vol. 197, p359-367. 9p.
- Subject
- *NEUTRON scattering
*QUASI-elastic scattering
*SMALL-angle neutron scattering
*NUCLEAR activation analysis
- Language
- ISSN
- 0008-6223
The self-diffusion mechanisms for adsorbed H 2 in different porous structures are investigated with in situ quasi-elastic neutron scattering method at a temperature range from 50 K to 100 K and at various H 2 loadings. The porous structures of the carbon materials have been characterized by sorption analysis with four different gases and the results are correlated with previous in-depth analysis with small-angle neutron scattering method. Thus, an investigation discussing the effect of pore shape and size on the nature of adsorbed H 2 self-diffusion is performed. It is shown that H 2 adsorbed in nanometer-scale pores is self-diffusing in two distinguishable timescales. The effect of the pore, pore wall shape and corrugation on the fraction of confined and more mobile H 2 is determined and analyzed. The increased corrugation of the pore walls is shown to have a stronger confining effect on the H 2 motions. The difference of self-diffusional properties of the two H 2 components are shown to be smaller when adsorbed in smoother-walled pores. This is attributed to the pore wall corrugation effect on the homogeneity of formed adsorbed layers. [Display omitted] • H 2 adsorbed in porous CDCs diffuses in two distinguishable timescales. • Larger difference between the two H 2 diffusional phases in corrugated pores. • Pore wall corrugation and shape influences H 2 diffusivity. • Enhanced H 2 confinement in corrugated pores compared to smoother-walled pores. [ABSTRACT FROM AUTHOR]