High-pressure Hydrogen Inclusion Compounds

Molecular hydrogen (H2) has been proposed as an alternative fuel source for vehicles. Though H2 has many benefits, such as clean combustion and the highest known energy density by mass, there are issues in how to store it in a safe and cost effective way. One solution is to store hydrogen in a chemical compound, and gas clathrates (crystalline inclusion compounds) have shown promising results.Neutron diffraction is the technique of choice for such materials since it can reveal the location and occupancy of the hydrogen sites and recent developments, such as a hydrogen-compatible gas loader for the Paris-Edinburgh press, enable high-pressure neutron diffraction studies of hydrogen storage materials. I shall give a brief overview of neutron diffraction at high pressures and present data from experiments on the hydrogen clathrates of hydroquinone, urea and water.