Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7836529 | Applied Surface Science | 2018 | 7 Pages |
Abstract
Hydrogen storage capacity on Titanium (Ti) decorated porous graphene (PG) has been investigated using density functional theory simulations with generalized gradient approximation method. The possible adsorption sites of Ti atom on PG and electronic properties of Ti-PG system are also discussed.The results show a Ti atom prefers to strongly adsorb on the center site above the C hexagon with the binding energy of 3.65Â eV, and the polarization and the hybridization mechanisms both contribute to the Ti atom adsorption on PG. To avoid a tendency of clustering among Ti atoms, the single side of the PG unit cell should only contain one Ti atom. For the single side of PG, four H2 molecules can be adsorbed around Ti atom, and the adsorption mechanism of H2 molecules come from not only the polarization mechanism between Ti and H atoms but also the orbital hybridization among Ti atom, H2 molecules and C atoms. For the case of double sides of PG, eight H2 molecules can be adsorbed on Ti-decorated PG unit cell with the average adsorption energy of â0.457Â eV, and the gravimetric hydrogen storage capacity is 6.11Â wt.%. Furthermore, ab inito molecular-dynaics simulation result shows that six H2 molecules can be adsorbed on double sides of unit cell of Ti-PG system and the configuration of Ti-PG is very stable at 300Â K and without external pressure, which indicates Ti-decorated PG could be considered as a potential hydrogen storage medium at ambient conditions.
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Authors
Lihua Yuan, Long Kang, Yuhong Chen, Daobin Wang, Jijun Gong, Chunni Wang, Meiling Zhang, Xiaojuan Wu,