First-principles calculations on the basis of density functional theory (DFT) as implemented in the Vienna ab initio simulation package (VASP) were performed to optimize the hexagonal lattices of the 2D binary polymers. The projector augmented wave (PAW) method was used to treat the ion-electron interactions for atoms. The generalized gradient approximation (GGA) involving the Perdew-Burke-Ernzerhof (PBE) functional with Grimme's D3 van der Waals correction was adopted to process the exchange-correlation term and accurately account for the weak interactions between the adsorbents and the 2D binary polymers. A convergence threshold of 1 × 10 -5 eV in energy and 1 × 10 -2 eV Å -1 in force were set with the conjugate gradient method. A cutoff energy of 500 eV for the plane wave basis set and the 3 × 3 × 1 Monkhorst-Pack k-point mesh for the hexagonal Brillouin Zone was utilized in all computations. The vacuum layer was set to be 15 Å along the c direction to avoid interactions between neighboring images.