Methodological, applied and thermodynamic aspects of hydrogen sorption by graphite and related carbon nanostructures

Abstract

We have investigated the damage induced by irradiation in Y 1 Ba 2 Cu 3 O 7−x silver added samples. The samples were prepared with 0 and 6.5 wt% of silver and irradiated by high-energy γ irradiation (50-150 Mrad). The roles of silver and dosage irradiation are discussed in terms of their effects on microstructure, crystallinity, critical temperature (T c ) and zero-resistance temperature (T 0 ). After irradiation, T c decreased while the room-temperature electrical resistance increased by a factor of 8 for some of the samples. The difference in T 0 between irradiated and non-irradiated YBCO samples was of the order of 10 K. We have found that the difference is bigger for silver-added samples. We have also observed several changes in diffraction patterns of YBCO and YBCO-silver samples. SEM images, EDS and XPS analysis showed that silver resided inside the grains as single atoms and as metallic clusters. The relative concentrations of the elements in samples were quantified by Auger electron spectroscopy. The J c values showed a gradual increase for radiation doses ranging between 0 and 100 Mrad. For doses up to 100 Mrad, J c decreased because of the weak-link breakage induced by high doses of γ rays.

Analytical Review on the Hydrogen Multilayer Intercalation in Carbonaceous Nanostructures: Relevance for Development of Super-Adsorbents for Fuel-Cell-Powered Vehicles

“…As has been shown in Refs. [3,4], only process II (from the considered ones I-IV in Table I) is characterized by an accompanying (initiated by the process) occurrence of a fairly small amount of hydrocarbons (CH 4 and others) in the thermal desorption (TD) spectra. The explanation 3 4 of this phenomenon is that the energy (− H 12 II , Table I) of desorption (detachment) of two hydrogen atoms from the carbon atom of the sorption center (model H in Fig.…”

“…reviews in Refs. [3,4]). Even though some reports claim very high storage capacity, such findings have not been supported by the majority of investigators.…”

A road to hydrogenating graphene by a reactive ion etching plasma

“…Estimation of the H content in micromechanically cleaved graphene flakes after hydrogen treatment is very difficult. The standard methods known from graphite, like thermal programmed desorption (TPD) [18][19][20], are insensitive to the possible amounts of desorbed hydrogen from micro-sized flake. Estimation of H coverage from scanning tunneling microscopy (STM) topography images carries limitations that STM probes the surface only locally, measurements are time consuming and difficult when graphene is deposited on the insulating substrate.…”

The effect of sorbed hydrogen on low-temperature radial thermal expansion of single-walled carbon nanotube bundles

“…In recent years much effort has been applied to understanding possible mechanisms of such "strong" physical (or "weak" chemical) interaction between H 2 and carbon nanomaterials. However, the ample experimental information accumulated during 1997-2005 about the capacity of CNTs to sorbe H 2 suffers significant (up to three orders of magnitude, e.g., see Surveys [8,9,15,[16][17][18]). Therefore, the fundamental aspects (mechanisms and characteristics) of the H 2 -CNT interaction are still topical and call for further consideration.…”