title: Volumetric apparatus for hydrogen adsorption and diffusion measurements: sources of systematic error and impact of their experimental resolutions.
abstract: The development of a volumetric apparatus (also known as a Sieverts' apparatus) for accurate and reliable hydrogen adsorption measurement is shown. The instrument minimizes the sources of systematic errors which are mainly due to inner volume calibration, stability and uniformity of the temperatures, precise evaluation of the skeletal volume of the measured samples, and thermodynamical properties of the gas species. A series of hardware and software solutions were designed and introduced in the apparatus, which we will indicate as f-PcT, in order to deal with these aspects. The results are represented in terms of an accurate evaluation of the equilibrium and dynamical characteristics of the molecular hydrogen adsorption on two well-known porous media. The contribution of each experimental solution to the error propagation of the adsorbed moles is assessed. The developed volumetric apparatus for gas storage capacity measurements allows an accurate evaluation over a 4 order-of-magnitude pressure range (from 1 kPa to 8 MPa) and in temperatures ranging between 77 K and 470 K. The acquired results are in good agreement with the values reported in the literature.
authors.affiliation: Dipartimento di Fisica, Università della Calabria, Via Ponte P. Bucci, Cubo 31C, 87036 Arcavacata di Rende (CS), Italy.
authors.forename: Alfonso
authors.initials: A
authors.lastname: Policicchio
authors.forename: Enrico
authors.initials: E
authors.lastname: Maccallini
authors.forename: Georgios N
authors.initials: GN
authors.lastname: Kalantzopoulos
authors.forename: Ugo
authors.initials: U
authors.lastname: Cataldi
authors.forename: Salvatore
authors.initials: S
authors.lastname: Abate
authors.forename: Giovanni
authors.initials: G
authors.lastname: Desiderio
authors.forename: Raffaele Giuseppe
authors.initials: RG
authors.lastname: Agostino