A first-principles study on adsorption behaviors of pristine and Li-decorated graphene sheets toward hydrazine molecules

摘要

Highlights•Pristine graphene sheet was proposed for N2H4molecule adsorption with weak physisorption.•Li-decorated graphene sheet is significantly sensitive to detect N2H4molecule.•The effect of concentrations of N2H4molecules adsorbed on pristine and Li-decorated graphene sheets was studied detailedly.AbstractThe adsorption behaviors and properties of hydrazine (N2H4) molecules on pristine and Li-decorated graphene sheets were investigated by means of first-principles based on density functional theory. We systematically analyzed the optimal geometry, average binding energy, charge transfer, charge density difference and density of states of N2H4molecules adsorbed on pristine and Li-decorated graphene sheets. It is found that the interaction between single N2H4molecule and pristine graphene is weak physisorption with the low binding energy of −0.026 eV, suggesting that the pristine graphene sheet is insensitive to the presence of N2H4molecule. However, it is markedly enhanced after lithium decoration with the high binding energy of −1.004 eV, verifying that the Li-decorated graphene sheet is significantly sensitive to detect N2H4molecule. Meanwhile, the effects of the concentrations of N2H4molecules on two different substrates were studied detailedly. For pristine graphene substrate, the average binding energy augments apparently with increasing the number of N2H4molecules, which is mainly attributed to the van der Waals interactions and hydrogen bonds among N2H4clusters. Li-decorated graphene sheet has still a strong affinity to N2H4molecules despite the corresponding average binding energy emerges a contrary tendency. Overall, Li-decorated graphene sheet could be considered as a potential gas sensor in field of hydrazine molecules.