Hydrogen Physisorption in Metal–Organic Porous Crystals

Abstract

Friction measurements were performed using gel samples equilibrated in distilled water against a glass substrate at room temperature, using a tribometer (Heidon 14S/14DR, Shindom Sci., Co.). The size of the gels was 20 mm 20 mm and they were 3 mm thick. The sample was embedded in a square frame of adjustable size and pressed against the glass surface that was fixed on the lower board. The glass surface was wetted with distilled water and was driven to move horizontally and repeatedly in a velocity range of 5 10 ±4 ±3 10 ±2 m s ±1 over a distance of 100 mm. Prior to the measurement, the glass plate was carefully washed with a cleaner, rinsed in distilled water, and dried in air. The measurements under various loads at a certain velocity were carried out using one sample, starting from the lower load and increasing the load continuously. The slidingvelocity dependence under a constant load was also measured in the same way. The detailed procedures are described elsewhere [10]. The frictional force per unit area (shear stress), f, and normal pressure, P, were calculated by dividing the frictional force, F, and load, W, by the surface area of the sample in the load-free state, respectively. The frictional coefficient, l, was calculated using the equation l = F/W.

H<sub>2</sub> and CH<sub>4</sub> Sorption on Cu-BTC Metal Organic Frameworks at Pressures up to 15 MPa and Temperatures between 273 and 318 K

“…[13,24,25]. Other studies report BET surface areas for this material of 1781 m 2 /g (single-point BET) [26], 1154 m 2 /g [7] and 1239 m 2 /g [11] which is similar to the BET surface area of 1246 m 2 /g ascertained in this study (all measured with N 2 at 77 K).…”

“…Specific surface areas (SSA) and pore size distributions (PSD) have been determined on untreated samples before and after high-pressure sorption experiments in order to detect any structural changes of the sample due to the interaction with the gases. A similar approach has been used by [7], who reported changes in SSA and PSD on MOF-5 during hydrogen sorption . Two slightly different MOFs both consist of the same organic ligands but with different basic metals (Al 3+ and Cr 3+ ) [8].…”

Hydrogen Adsortion in Periodic Mesoporous Organic– and Inorganic–Silica Materials at Room Temperature

“…1 However, Hirscher and Panella also measured the hydrogen uptake of MOF-5 under the same conditions and found it is nearly 20 times less, 0.05 wt %, than the previously reported value. 10 Therefore, the exceptional results initially reported could not be confirmed. Although several hydrogen uptake materials are now known, they are not useful for practical applications of hydrogen-storage due to the necessity for rather extreme temperature and pressure conditions.…”

MOF–Graphite Oxide Composites: Combining the Uniqueness of Graphene Layers and Metal–Organic Frameworks

“…[20,29] Nevertheless, surfaces of similar magnitude were reported by Huang and coworkers, and Panella and coworkers. [34,35] The difference in the surface area can be related to the way of outgassing during preparation and thus the completeness of solvent removal. Other factors such as the temperature at which crystals were formed were also indicated as potentially affecting the porosity.…”