Adsorption of CO 2 in carbon nanohorns Silvina M. Gatica, Howard University, DMR 1006010

1. Adsorption of CO2 in carbon nanohornsSilvina M. Gatica, Howard University, DMR 1006010 Among several gases, carbon dioxide (CO2) became particularly interesting due to new measurements of the isosteric heat of adsorption (Qst) of CO2 in carbon nanohorns (CNHs). Experimental results show a “u-shaped” curve Qst vs coverage, that is not seen in other gases. We conducted a pre-study of CO2 in a bundle of carbon nanotubes (CNTs) with the purpose of: i) figuring out if similar u-shaped behavior is found in CNTs , ii) test the model of the carbon-CO2 interaction and iii) compare results of CNHs and CNTs. The computed Qst shows a “u-shape” exclusively at the higher temperature. The temperature dependence of the Qst is not clear and needs further studies. (a) (b) Uptake of CO2 in the groove between two carbon nanotubes (a) and isosteric heat vs coverage (b)

2. Adsorption of CO2 in carbon nanohornsSilvina M. Gatica, Howard University, DMR 1006010 • Broader Impacts • This grant has financed the work of two students at Howard University: • Mamadou Mbaye (graduate student), has made significant progress in his thesis on “Adsorption of gases on carbon nanostructures”. His proposal has been submitted to the Graduate School in August 2012. Mr. Mbaye will defend in May 2012. • Mayra Medina (undergraduate student) has worked on research projects in the summer 2011 and 2012. She presented her results in the Undergraduate Symposium at Howard University. Ms. Medina graduated in May 2012 and has been accepted to Medical School, HU. The figure represents the potential energy of a two CO2 molecules in the groove next to two parallel carbon nanotubes, as calculated by Ms. Medina. From her results she concluded that the configuration with the lowest energy (thermodynamically speaking, most stable) is the transverse-axial arrangement.