Kinetic Process of Graphene Growth from Dual-Carbon Sources on Alpha Alumina

As a new member of the super graphene-skinned materials family, graphene-skinned alumina material integrates the excellent characteristics of graphene and alumina, with characteristics like high electrical conductivity and thermal conductivity, light weight, and has broad application prospects in integrated circuits, electric heating, wind power deicing. Based on density functional theory, the cracking, migration of major carbon species, nucleation, and edge growth of ethylene and acetylene on the α-Al₂O₃(0001) plane are investigated. The results show that: 1) α-Al₂O₃ substrate has metal-like catalytic activity, the pyrolysis products of C₂H₂ and C₂H₄ carbon sources are C₂H and C₂H₂, respectively, and the main active species on the substrate surface are C₂H; 2) The adsorption properties and nucleation rate of C₂H on the substrate surface are better than C₂H₂, but C₂H is more difficult to migrate than C₂H₂, and their migration energy barriers are 2.80/0.88 eV, respectively; 3) The microscopic mechanism of the preparation of graphene-skinned alumina materials by dual-carbon sources is that: the dual-carbon sources are cracked into C₂H and C₂H₂, then C₂H nucleates to form graphene nuclei on the substrate surface, finally C₂H₂ participates in the edge growth of graphene on the substrate, and the AC(Armchair) edge growth rate is faster.