Microscopic characterization of metal-carbon-hydrogen composites (metal = Li, Mg)

Abstract

Li-C-H system, which can store about 5.0 mass% of rechargeable H 2 , has been reported as a promising hydrogen storage system by Ichikawa et al. [Appl. Phys. Lett. 86, 241914 (2005); Mater. Trans. 46, 1757Trans. 46, (2005]. This system was investigated from the thermodynamic and structural viewpoints. However, hydrogen absorption/desorption mechanism and the state of hydrogen atoms absorbed in the composite have not been clarified yet. In order to find new or better hydrogen storage system, graphite powder and nano-structural graphite ball-milled under H 2 and Ar atmosphere were prepared and milled with Li and Mg under Ar atmosphere in this study. Microstructural analysis for those samples by transmission electron microscope revealed that LiC 6 and/or LiC 12 were formed in Li-C-H system. On the other hand, MgC 2 was found in Mg-C-H system ball-milled under H 2 atmosphere, but not in the system ball-milled under Ar atmosphere. These results indicated that nano-structure in composites of nano-structural graphite is different from that of alkali (-earth) metal. For these reasons, metal-C-H system can be recognized to be a new family of hydrogen storage materials. V C 2013 AIP Publishing LLC.

Synthesis of pyrimidines from dinitrogen and carbon

“…the hydridic H in the solid solution is an electron source for continued N 2 reduction and perhaps also for the activation of C for subsequent C–N coupling. The involvement of hydride species in carbon reduction has also been identified in previous reports [ 36 ].…”

Synthesis of destabilized nanostructured lithium hydride via hydrogenation of lithium electrochemically inserted into graphite

“…Miyaoka et al [7] studied hydrogen sorption properties of (Li þ 2C) ground mixture and revealed that the hydrogenated Ligraphite sample desorbed only H 2 from 150 C with a complex mechanism since Li 2 C 2 , LiH and LiC 12 were present after desorption. Thereafter, Isobe et al [8] carried out microscopic characterization for these hydrogenated/dehydrogenated Li-graphite samples and indicated that LiH was generated at the edge site of graphite.…”

Hydrogen Storage in Porous Single-Walled Carbon Nanohorns Dispersed with Pd–Ni Alloy Nanoparticles

“…Current research in clean energy can be characterized by the considerable effort taken to promote clean energy technologies that do not produce CO 2 exhaust. It is believed that H 2 is a promising source of clean energy, and many attempts have been made to overcome the barriers to make it a feasible energy source. , One of the most important hurdles that needs to be overcome is finding an effective method to store H 2 . − To date, the methods investigated for this purpose can be categorized in three groups: (i) absorption of H 2 in alloys, − (ii) physisorption onto large surfaces, − and (iii) liquid organic hydrogen carriers (LOHC). , Among these methods, research into H 2 absorption in alloys has a long history, and the related knowledge has accumulated to a considerable level.…”