Influence of gas molecule adsorption on the mechanical properties of the graphene/aluminum interface

The graphene/aluminum (Gr/Al) interface plays a critical role in determining the mechanical properties of Gr/Al composites. During fabrication and service, the adsorption of gas molecules at the interface can significantly influence the mechanical properties. In this study, density functional theory (DFT) is employed to simulate the adsorption of H₂, O₂ and CO₂ at the Gr/Al interface and the associated changes in electronic structure and mechanical properties are systematically investigated. The simulation results reveal that O₂ adsorption increases the interface binding energy but reduces the ideal strength, owing to the pronounced resonance peaks formed between O-p orbitals and Al-p\C-p orbitals, which destabilize the interface. H₂ adsorption leads to direct interaction between H₂ molecules and the aluminum matrix, thereby affecting the interface mechanical performance. By contrast, CO₂ adsorption exhibits negligible interaction with the aluminum matrix, resulting in the integrity maintenance of the Gr/Al interface with the highest ideal strength. Further analysis demonstrates that the elastic behavior of the interface is mainly dominated by the aluminum matrix, whereas structural failure originates from the fracture of the graphene structure.