Influences Of The Moire Pattern On Properties Of Double-layered Graphenes With Single Adsorptive Catalyst

The graphene-based single-atom adsorbed system has great potential in catalysis applications with high catalytic activity.The structure stability and catalysts activity of catalysts system are depended on the electronic structure near the catalytic site.The interlayer lattice mismatch has an effect on the electronic structure in the twisted bilayer graphene system(t BLG),and the Moiré pattern which is totally depended on the interlayer twist angle is an important method to characterize such mismatch in t BLG.The goal of this work is to establish preliminary relation between the structure stability and adsorbed ability with respect to the twist angle in t BLG,by using DFT calculations.In this work,we defined new geometrical mismatch parameters to quantitatively describe the local lattice mismatch status in the twisted bilayer graphene system.The defined parameters have been verified by comparing to Moiré patterns and visually observed local structures.Based on the mismatch parameters,we categorized the lattice sites into specific mismatch types,which guided us to construct DFT testing models for binding energy(Eb)and adsorption energy(Ea)calculations.By performing correlation studies on Eb and Ea with various geometrical parameters,such as the size of the periodic cell,the twisting angle,and averaged values of binds and angles formed by different types of atoms.We observed both energies change with the size of the periodic cell in a layeredmonotone pattern,where the Eb is dominated by the monotonic part and increases with the cell size,while the Ea is dominated by the layered part.For Eb inside each layer,the value decreases monotonically with cell size.These relations yield a V-shape like relation between the Ea and Eb,suggesting the existence of some specific angles where the structural stability and catalytic performance are optimal combinations.Meanwhile,the cell size can be related to the twisting angle by a simple analytical relation,meaning we can predict both energies at given angles based on their relations with the cell size.In addition,the results of some preliminary electron density state calculations indicate changes in the symmetry of the system density state appears for different twisting angles.