Browsing by Author "Liu, Xiao"
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Item A First-Principles Study of Sodium Adsorption and Diffusion on Phosphorene(Royal Soc Chemistry) Liu, Xiao; Wen, Yanwei; Chen, Zhengzheng; Shan, Bin; Chen, RongThe structural, electronic, electrochemical as well as diffusion properties of Na doped phosphorene have been investigated based on first-principles calculations. The strong binding energy between Na and phosphorene indicates that Na could be stabilized on the surface of phosphorene without clustering. By comparing the adsorption of Na atoms on one side and on both sides of phosphorene, it has been found that Na-Na exhibits strong repulsion at the Na-Na distance of less than 4.35 Å. The Na intercalation capacity is estimated to be 324 mA h g⁻¹ and the calculated discharge curve indicates quite a low Na⁺/Na voltage of phosphorene. Moreover, the diffusion energy barrier of Na atoms on the phosphorene surface at both low and high Na concentrations is as low as 40-63 meV, which implies the high mobility of Na during the charge/discharge process.Item Tunable H₂ Binding on Alkaline and Alkaline Earth Metals Decorated Graphene Substrates from First-Principles Calculations(Pergamon-Elsevier Science Ltd, 2017-04-13) Wen, Yanwei; Xie, Fan; Liu, Xiaolin; Liu, Xiao; Chen, Rong; Cho, Kyeongjae; Shan, Bin; 0000-0003-2698-7774 (Cho, K); 369148996084659752200 (Cho, K); Cho, Kyeongjae; Shan, BinBased on first-principles calculations, the H-2 adsorptions onto six types of modified graphene substrates decorated with light metals (Li, Na, K, Be, Mg, Ca) are investigated to shed light on the factors affecting the H-2 binding energies. It is demonstrated that the introduction of defects and dopants into graphene substrates is essential to prevent the metal clustering and achieve dispersed metal atoms desirable for H-2 adsorption. The interaction between H-2 and alkali/alkali-earth metal decorated graphene systems is attributed to the electrostatic effect induced by polarized dipole-dipole interaction. Via introducing defects and hetero-atoms to modify the electronegativity of the local structure, the H-2 adsorption energy can be tuned by choosing the combination of suitable metals and substrates. The calculated H-2 binding strength is positively correlated to the charge transfer from the metal to the substrates and the dipole momentum of metal decorated substrates. Compared the cases with different metals decoration, Mg and Ca are expected to the most promising candidates for multiple H-2 adsorptions.