Effect of dopants and defect in graphene nanoribbons on dehydrogenation of MXH₄, where M=Na,Li and X=Al,B

The present paper reports the effect of Graphene Nanoribbons (GNRs) for improving the dehydrogenation of MXH₄, where M=Na,Li and X=Al,B through density functional calculations. The rectangular Armchair GNRs and ZigZag GNRs with width up to 7.57 Å & 10 Å and length of 15 Å &10 Å respectively were considered for the investigation. The effect of dopant and defect was introduced by doping with different dopants (B,N,Al,Cl and F) and introducing vacancy defect respectively. The MXH₄ interacts with the surface atoms of GNRs with binding energy from 0.31–0.89 eV with AGNR and from 0.26 eV to −1.42 eV with ZGNR respectively. Charge transfer of 0.12–0.26 e take place from GNR surface to MXH₄ molecule resulting in significant decrease in hydrogen release energy (E_HRE). Doped and defective AGNR lowers E_HRE of MXH₄ sharply by 19–56% whereas ZGNR decreases E_HRE by 18–70% respectively. The results agree qualitatively with the available experimental result and outline the importance of nano carbon as a catalyst for improving the performance of light complex metal hydride systems.