The effect of electric field on Ti-decorated graphyne for hydrogen storage

Hydrogen adsorption on Ti-decorated graphyne under different external electric fields is explored by first-principles calculations. Through the analyses of structural and electronic properties of pristine and Ti-decorated graphyne, we find that the most favorable adsorption site of Ti atom is the hollow site of a 12-C hexagon. For a single H2 adsorbed on Ti-decorated graphyne, the adsorption energy increases dramatically with the electric field intensity increasing, and the maximum adsorption energy is 0.72 eV when the electric field is 0.014 a.u. The interaction between H2 molecule and Ti-decorated graphyne is Kubas interaction under an external electric field. Each Ti atom can adsorb four hydrogen molecules. The analysis of electronic properties shows that the interaction between Ti and H increases when the electric field is applied. However, the interaction is not as strong as that for a single H2 adsorption.