Facile and Non-Destructive Probe of Hydrogen Content in Hydrogenated Graphene: A Neutron Scattering Study*

Defects and functionalization can be used to modify graphene’s physical properties such as changing its conductivity or inducing ferromagnetism, which could be of interest for spintronics. Here we investigate hydrogenated graphene nano-powder that has been produced by Birch reduction and is comprised of 3-4 layer flake thicknesses. One significant challenge in assessing these materials is the ability to determine the amount of hydrogen that has been incorporated into the graphene. We show that neutron incoherent scattering is an effective and non-destructive means to make this determination. Two methods are compared, the scattering and transmission of neutrons, which yield a consistent H:C ratio of 35% for our Birch-reduced hydrogenous graphene. Neutron and x-ray powder diffraction show that the layer spacing of 3.85 Å between the graphene sheets is significantly expanded compared to pristine graphene, indicating that H attaches onto the graphene planes. Our study demonstrates a simple, effective, and nondestructive method of characterizing H content in bulk graphene materials.