Hong-Cai Zhou's team at Texas A&M University has developed many unique porous metal-organic frameworks (MOFs) for hydrogen and methane storage. MOFs are especially designed porous materials that can hold large amounts of gases, some at levels higher than those targeted by the U.S. Department of Energy.
Efficient hydrogen storage remains a bottleneck for the upcoming hydrogen economy. However, MOFs may offer a solution because of the distinctive qualities they possess such as large, overall pore volume and surface area, adjustable pore sizes and a tunable framework.
These remarkable materials can potentially fill the niche between other physisorbents, such as activated carbon, that have similar uptake capacities at low temperatures but little attraction to hydrogen at ambient temperature, and chemical sorbents such as hydrides, that have high hydrogen uptakes but undesirable release energy and heat issues.
Team members continue to explore the potential of novel, efficient, inexpensive and environmentally friendly sorbents to store energy-related gases such as hydrogen, methane and carbon dioxide. MOFs are crystalline frameworks consisting of metal ions and organic ligands--ions or molecules that bind to the metal ions. In some cases, pores inside an open MOF are stable after removal of guest molecules (often solvents) and the MOF can be used for gas storage.
The compounds studied by the Zhou group were characterized through diffraction studies using the high-energy beamline at ChemMatCARS, a high-brilliance synchrotron X-ray facility supported by NSF.