(558bc) Choline Chloride-Urea Based Deep Eutectic Solvent As Chemical and Physical Means of Hydrogen Storage

McGaughy, K., Ohio University
Reza, M. T., Ohio University
In the effort to move to sustainable energy resources, hydrogen storage and transportation are important to the efficient implementation of these energy sources, such as fuel cells. Hydrogen can be physically transported by compressing hydrogen gas, absorbing the hydrogen in a solvent, adsorbing the hydrogen onto a functionalized surface, or any combinations of these methods. Additionally hydrogen can be chemically transported by utilizing a hydrogen source such as urea. Unfortunately, each of these methods of transportation has a drawback, such as expensive compression or the use of irreversible hydrogen storage chemicals. Moving to a system that utilizes both physical and chemical storage can maximize the transportation of hydrogen. Choline chloride and urea solutions belong to a class of chemicals that interact via a eutectic bonding phenomenon. This bond results in a solution that has a lower melting point compared to either component. Additionally, water may be added to reduce viscosity and boiling point even further. This solution, referred to as reline, has an extremely low vapor pressure and enhanced solvation properties for gases. COSMOTherm, a density functional theory based molecular modeling software, is used to estimate the Henry’s law constants of hydrogen in non-aqueous and aqueous reline solutions. These results are checked with other gases that have documented Henry law constants to verify the simulation methodology is reliable. These results are then compared to industrial standards, such as simply shipping urea as a chemical hydrogen source, or compression hydrogen into a tanker and shipping it.