Exploring graphdiyne - Dynamic characterisation of the surface oxidation mechanisms via ReaxFF-MD and experiments

Graphdiyne (GDY) is an emerging two-dimensional carbon allotrope comprising unique sp(1) and sp(2) hybridisation, which has attracted extensive investigation into various applications, especially as battery component materials owing to its excellent electromechanical properties. However, GDY's thermal stability and oxidation behaviour have yet to be evaluated, which is crucial to safety in high-energy applications. The present study characterised the thermophysical properties of GDY via reactive molecular dynamics (MD-ReaxFF) and experimental measurement. The oxidation kinetics and decomposition behaviour were elucidated and benchmarked with graphene (GP) and graphyne (GY) to investigate the correlation between thermal stability and morphology of carbon nanomaterials. The simulation results revealed the initial oxidation mechanism of GDY sheets, where the cleavage of C-C bonds was observed at the acetylenic chain and could be identified as the weak spots of the structural stability. As for oxidation kinetics, GDY's experimental and numerical activation energy was found to be 173.1 and 133 kJ/mol, which is lower than 220.8 kJ/mol of GP. The current work pioneer investigated the thermal stability of GDY using both experimental and numerical approaches. Meanwhile, different oxidation mechanisms between GP and GDY were distinguished and demonstrated in detail.