화학공학소재연구정보센터
International Journal of Hydrogen Energy, Vol.43, No.52, 23346-23356, 2018
Calcium-decorated graphdiyne as a high hydrogen storage medium: Evaluation of the structural and electronic properties
Graphdiyne (GDY) is a new member of carbon allotropes consisting of sp and sp(2) hybridized carbon atoms. In this work, the hydrogen adsorption on Calcium (Ca) decorated GDY and the influence of adatom on structural properties of GDY are investigated, using first principles plane wave calculations with Van der Waals corrections. The results show that similar to graphyne (GY) and unlike carbon nanotube (CNT), fullerene and graphene, clustering of Ca on GDY hinders due to the higher binding energy of the adatom to the carbon frame than the Ca cohesive energy. It can be seen that the Ca-decoration promotes hydrogen storage capacity of GDY, extremely (E-ads = -0.266 and -0.066 eV for Ca-decorated and pristine GDY, respectively). It is concluded that, the best site for the Ca trapping is 18-membered ring in which, Ca lies in-plane of GDY (E-ads = -3.171 eV). Fourteen H-2 molecules (with the average adsorption energy of similar to 0.2 eV/H-2) can be adsorbed on the Ca atom from one side. The hydrogen storage capacity is estimated to be as high as 17.95 wt% for the both sides of GDY. So, the Ca-decorated GDY is offered as a promising candidate for hydrogen storage applications. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.