Adsorbents with excellent CO₂ capture and separation performances are critical in reducing the excessive CO₂ concentration in the atmosphere. Herein, alkali/alkaline earth metals doped graphynes (AM_n-GYs, AM = Li, Na, K, Mg and Ca; GY = graphyne; n = 0.5, 1, and 2) were evaluated by employing grand canonical Monte Carlo and density functional theory approaches. The results showed that AMs were strongly bonded on GY with binding energies of −0.09 to −2.52 eV and diffusion barriers of 5.20–16.32 eV. Electronic structure analyses proved that there was a strong covalent bond, large charge transfer, and distinct orbital overlap characters between the AMs and GY, thus constructing a stable and feasible gas adsorption environment. Among all structures, AM₁-GYs with one AM doping in a GY unit cell displayed the best CO₂ adsorption behavior. Thereafter, Li₁/Na₁/K₁-GY with a pore size of 6.60 Å and Mg₁/Ca₁-GY with a pore size of 6.50 Å were screened as the potential adsorbents. In comparison, the best performing Ca₁-GY had an ultra-high CO₂ adsorption capacity of 9.01 mmol/g at 298 K and 1 bar, which was superior to most of the previously reported adsorbents. At 298 K and 1 bar, the CO₂ selectivity over N₂/CH₄ for Ca₁-GY reached 2246 and 5602, respectively. Interaction and gas distribution analysis confirmed that comparing to other AM₁-GYs, Ca₁-GY has a stronger affinity with CO₂ and larger isosteric heat differences between CO₂ and other gases, rendering Ca₁-GY to possess excellent adsorption capacity and selectivity.

具有出色 CO ₂捕获和分离性能的吸附剂对于降低大气中过量的 CO ₂浓度至关重要。在此，碱/碱土金属掺杂的石墨烯（AM _n -GYs，AM = Li、Na、K、Mg 和 Ca；GY = 石墨炔；n = 0.5、1 和 2）通过使用正则蒙特卡罗和密度进行评估功能理论方法。结果表明，AMs 与 GY 牢固结合，结合能为 -0.09 至 -2.52 eV，扩散势垒为 5.20-16.32 eV。电子结构分析证明，AMs和GY之间存在强共价键、大电荷转移和明显的轨道重叠特征，从而构建了稳定可行的气体吸附环境。在所有结构中，AM在 GY 晶胞中掺杂一种 AM 的₁ -GY 表现出最佳的 CO ₂吸附行为。此后，筛选出孔径为6.60 Å 的Li ₁ /Na ₁ /K ₁ -GY 和孔径为6.50 Å 的Mg ₁ /Ca ₁ -GY 作为潜在的吸附剂。相比之下，性能最好的 Ca ₁ -GY在 298 K 和 1 bar 下具有 9.01 mmol/g的超高 CO ₂吸附容量，优于大多数先前报道的吸附剂。在 298 K 和 1 bar 条件下，Ca _{1 相}对于 N ₂ /CH ₄的 CO ₂选择性-GY 分别达到 2246 和 5602。相互作用和气体分布分析证实，与其他AM ₁ -GY相比，Ca ₁ -GY与CO _{2 的}亲和力更强，CO ₂与其他气体的等量热差更大，使Ca ₁ -GY具有优异的吸附能力和选择性.