Jason M. Simmons1and Taner Yildirim1,2

1NIST Center for Neutron Research, 2University of Pennsylvania


Environmental concerns have lead to extensive research into reducing the amounts of carbon that are released into the atmosphere during energy generation and use.  This can be achieved through the use of alternative fuels, particularly for transportation applications (H2 and CH4/natural gas), as well as by the efficient capture of carbon (CO2) from the effluent stream of current energy technologies.  In each case, a better understanding of the guest-host interactions is of utmost importance.  Here we discuss the results of gas sorption and neutron scattering studies of high surface area and functionalized nanoporous materials in order to improve their impact on each of these important storage problems.


In order to probe the guest-host interaction, we use a home-made, fully computer controlled Sievert apparatus which can operate continuously in a wide range of temperatures (30K to 500 K) and pressures (vacuum to 60 bar).  This system allows for a variety of gas sorption studies including isothermal, kinetic, and temperature-programmed adsorption/desorption cycles. In particular, we found that the NIST real-gas equation of state at high pressures and low temperatures is critical to obtain accurate and correct data.  The results from these measurements are then combined with neutron scattering and computational modeling to achieve a detailed picture of the adsorption mechanisms.  In particular, we demonstrate stable room temperature hydrogen storage in a transition-metal (TM) doped nanoporous silica, providing an experimental proof of concept for TM-decorated nanoscructures as novel storage materials that was recently predicted by NCNR members.  For methane and carbon dioxide, we study the use of nanoporous carbons and metal-organic frameworks (MOFs) as room temperature gas storage media and highlight the structural features that lead to high sorption capacities.  Our work has lead to the discovery of the first metal-organic framework to exceed the U.S. Department of Energy target for viable methane storage as well as lead to the better understanding of the use of different types of MOFs for the optimization of carbon capture separate from the ultimate carbon storage or sequestration.  The studies presented here offer insight that should aid in future materials design to address the reduction of environmental carbon emission.



CATEGORY: Materials


Mentors Name: Taner Yildirim

Division 610, NIST Center for Neutron Research

Rm. A121, Building 235, MS: 6102

Tel: x5631