Multilayer graphane synthesized under high hydrogen pressure

Abstract

A new hydrocarbonhydrographitewith the composition close to CH is shown to form from graphite and gaseous hydrogen at pressures above 2 GPa and temperatures from 450 to 700°C. Hydrographite is a black solid thermally stable under ambient conditions. If heated in vacuum, it decomposes into graphite and molecular hydrogen at temperatures from 500 to 650°C. Powder X-ray diffraction characterizes hydrographite as a multilayer "graphane II" phase predicted by ab initio calculations [Wen X-D et al. PNAS 2011;108:6833] and consisting of graphane sheets in the chair conformation stacked along the hexagonal c axis in the −ABAB− sequence. The crystal structure of the synthesized phase belongs to the P6 3 mc space group. The unit cell parameters are a = 2.53(1) Å and c = 9.54(1) Å and therefore exceed the corresponding parameters of graphite by 2.4(2)% and 42.0(3)%. Stretching vibrations of C-H groups on the surface of the hydrographite particles are examined by infrared spectroscopy.

Bulk graphanes synthesized from benzene and pyridine

“…P.S. When this article was under preparation, it was reported in [40] that weakly ordered graphane-leke materials with stoichiometry close to 1:1 were obtained by the hydration of a disordered graphite nanopowder at a high pressure. The degree of ordering of the materials obtained in [40] is much lower than that in our samples.…”

Carbon clusters formed from shocked benzene

“…Instead, the expanded layer spacing may be attributed to graphane forms composed of hydrogenated carbon sheets. Multilayer graphane also referred to as hydro-graphite or graphate, has been theoretically predicted and synthesized 45 , 46 . Experimentally, stable hydro-graphite adopts a graphate-II or “buckled” structure composed of weakly coupled single graphane layers in a chair conformation.…”

Effect of Toluene Addition in an Electric Arc on Morphology, Surface Modification, and Oxidation Behavior of Carbon Nanohorns and Their Sedimentation in Water

“…The pyrolysis of toluene in the arc can be accompanied by the formation of methyl radicals [ 50 , 51 , 52 ], methylene molecules, and CCH 2 radicals [ 53 ], which interact with the CNH surface to form –CH 3 and –CH 2 groups. Asymmetric and symmetric vibrations in CH 3 cause peaks 1 and 5 in Figure 5 b,c, respectively; peak 2 is due to the asymmetric vibration of CH 2 and CH fragments; peak 3 corresponds to the asymmetric vibration of the CH 2 fragment; peak 4 is due to the bending in CH 3 and CH 2 fragments [ 54 , 55 ]. As the toluene content increases from 2.4 to 8.0 mL, the intensities of these peaks increase significantly.…”