Evaluation of the hydrogen adsorption onto Li and Li+ decorated circumtrindene (C36H12): A theoretical study

Abstract

Circumtrindene as a π-bowl shaped carbon structure decorated by Li and Li+ and examined for H2 adsorption using M06-2X/6-311++G(d,p)//B3LYP/GEN level of theory. All polygons, bonds and various carbon types, in concave and convex sides, were examined to find the best location for Li and Li+. ZPE and BSSE-corrected interaction energy values were calculated for connection of Li or Li+ to circumtrindene and for connection of H2 to LiC36H12 or Li+-C36H12. Better understanding of the adsorption properties were achieved by DOS, PDOS, OPDOS diagrams and NBO analysis. Results showed that in LiC36H12 and Li+-C36H12 complexes, the concave side has more binding energy than the convex ones and Li+-C36H12 has more binding energy than LiC36H12. Also, for LiC36H12, when Li was in center polygon and concave side and for Li+-C36H12, when Li+ was in 6-2 polygon and convex side, the highest interaction energy were obtained. For H2 adsorption, the complexes contain Li and Li+ in center polygon and concave face have the highest binding energy, equal to 15.72 and 16.29 kcal mol−1, respectively. Binding energy values indicated that adsorption of Li or Li+ onto C36H12 and adsorption of H2 onto LiC36H12 or Li+-C36H12 in all positions are chemisorptions, but the connections are not so strong for H2 molecules.