Interfacial chemical bonding between carbon nanotube and aluminum substrate modulated by alloying elements

• The effects of alloying elements on the interface between CNT and Al are revealed.
• The chemical bonding is detected between CNT and Al substrate doped with Sc and Ti.
• Bonding character is not fully reflected by the interfacial binding energy (Eb).
• Interaction potential energy and restructuring energy competitively affect the Eb.

The effects of alloying elements (Mg, Zn, Cu, Sc and Ti) on the interfacial bonding between a carbon nanotube (CNT) and an Al(111) surface are studied systematically using first-principles total energy calculations. The redistribution of the charge density of the Al(111) surfaces induced by the five alloying elements, the projected densities of state, and the crystal orbital Hamilton population analysis of the atomic pairs in the vicinity of the interface are analyzed in detail. Thereby, it is revealed that the bonding characteristic between the CNT and the Al(111) surfaces are modified when alloying with the early transition metals Sc and Ti that occupy subsurface positions. Also for the other alloying elements a weak interaction between CNT and the substrates is found although these elements occupy surface positions in the Al(111) surface. Through a detailed study of the interaction potential energy and the restructuring energy, we demonstrate that different mechanisms are responsible for the substrate–CNT interactions.

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