Searching for Magnetism in Hydrogenated Graphene: Using Highly Hydrogenated Graphene Prepared via Birch Reduction of Graphite Oxides

Abstract

Fully hydrogenated graphene (graphane) and partially hydrogenated graphene materials are expected to possess various fundamentally different properties from graphene. We have prepared highly hydrogenated graphene containing 5% wt of hydrogen via Birch reduction of graphite oxide using elemental sodium in liquid NH3 as electron donor and methanol as proton donor in the reduction. We also investigate the influence of preparation method of graphite oxide, such as the Staudenmaier, Hofmann or Hummers methods on the hydrogenation rate. A control experiment involving NaNH2 instead of elemental Na was also performed. The materials were characterized in detail by electron microscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, Raman spectroscopy both at room and low temperatures, X-ray fluorescence spectroscopy, inductively coupled plasma optical emission spectroscopy, combustible elemental analysis and electrical resistivity measurements. Magnetic measurements are provided of bulk quantities of highly hydrogenated graphene. In the whole temperature range up to room temperature, the hydrogenated graphene exhibits a weak ferromagnetism in addition to a contribution proportional to field that is caused not only by diamagnetism but also likely by an antiferromagnetic influence. The origin of the magnetism is also determined to arise from the hydrogenated graphene itself, and not as a result of any metallic impurities.

Heteroatom modified graphenes: electronic and electrochemical applications

“…Hydrogenation can be in general carried out by low pressure H 2 plasma hydrogenation, 61 high pressure (hundreds of atm) hydrogenation 64 or wet chemistry hydrogenation, which involves either the Birch reaction in liquid ammonia 68 or hydrogenation with nascent hydrogen.…”

Dirac Material Graphene

“…Thorough analysis, performed in each case, allowed excluding the impure origin of these features and attributing them to graphite/graphene itself, albeit induced by either micro-and/or nano-structuring of the samples or by defects of different topology created in due course of chemical modification (see some example [38][39][40][41]). It is important to mention that practically in all the cases a ferromagnetic response at room temperature was observed for graphene species with zero total spin density.…”

“…It is important to mention that practically in all the cases a ferromagnetic response at room temperature was observed for graphene species with zero total spin density. Another scenario concerns magnetic graphene of a paramagnetic behavior [40][41][42] recorded after either fluorination or bombarding graphene laminates consisting of 10-50 nm sheets by protons. The treatment provided the rupture of double C=C bonds inducing 'spinhalf paramagnetism' in graphene.…”

Temperature-tuned ferromagnetism in hydrogenated multilayer graphene

“…9 However, from the experimental point of view, the hydrogen adsorption process is blind to the graphene lattice, which explained the low magnetism we could obtain regardless of the high defect degree on the graphene surface. [10][11][12] While it is worth mentioning that it is now practically feasible to control the adsorption and desorption of single hydrogen atoms on the surface of graphene with new developments in techniques, such as STM imaging and feedback-controlled lithography, 13,14 but these methods can't be extended to industrial scales. It is also suggested theoretically preparing semi-hydrogenated graphene from graphane using physical method, such as applying an external electric eld 15 or applying pressure on a uorinated BN sheet supported on a graphane sheet.…”