Investigation of morphology and hydrogen adsorption capacity of disordered carbons Lilin He a, * , Yuri B. Melnichenko a , Nidia C. Gallego b , Cristian I. Contescu b , Junjie Guo b , Jitendra Bahadur a a Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States b Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States ARTICLE INFO Article history: Received 1 April 2014 Accepted 15 August 2014 Available online 22 August 2014 ABSTRACT Small angle neutron scattering (SANS), scanning transmission electron microscopy (STEM) and gas adsorption, were applied to study the morphology and hydrogen adsorption prop- erties of a wood-based ultramicroporous carbon (UMC) and a poly(furfuryl alcohol) derived carbon (PFAC). The polydispersed spherical model and the Guinier analysis of the scattering profiles were applied to obtain morphological parameters such as average pore size and pore size distribution of the two carbons; the results agreed reasonably well with indepen- dent gas sorption measurements and structural analysis by electron microscopy. The den- sity of hydrogen physisorbed in these two carbons at room temperature and at moderate pressures was investigated by in situ SANS measurements. The experimental data, ana- lyzed using a modified Kalliat model for decoupling scattering contributions from pores of different sizes, indicate that the molecular hydrogen acquires high densities preferen- tially in pores of subnanometer size at all measured pressures. These results support exist- ing quantum mechanical and thermodynamical models that have predicted that the narrowest pores enhance the adsorption due to the overlapping of the potential fields from both wall sides in the slit-like pores. The structural information at a nanometer level gained via this work could guide the new development of porous-carbon based materials for hydrogen storage. Published by Elsevier Ltd. 1. Introduction Limited fossil fuel reserves have spurred tremendous interest in developing new processes for supplying the world’s energy needs [1]. Fuel cell technologies are one of the strongest can- didates to replace gasoline and coals, hence mitigating con- cerns about pollution, global warming and exhausting of nonrenewable energy sources [2]. For fuel cell technology, hydrogen is the most attractive energy carrier due to its energy density and non-pollution feature (i.e, it can be pro- duced from renewable sources) [3]. However, there are several key technical barriers that have to be tackled before the hydrogen fuel cell vehicles can be widely commercialized. One of those challenges is to achieve an efficient, economical and safe mechanism for on-board H 2 storage [4–6]. Several years ago, the US Department of Energy (DOE) proposed a set of technical targets for on-board storage system, however, to date, no approaches or materials have been found to satisfy all of the requirements regarding efficiency, weight, cost, and safety for transportation [5,7]. Current research activities http://dx.doi.org/10.1016/j.carbon.2014.08.041 0008-6223/Published by Elsevier Ltd. * Corresponding author. E-mail address: hel3@ornl.gov (L. He). CARBON 80 (2014) 82 – 90 Available at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/carbon