电荷与应变协同调控g-C9N7膜对CO2吸附和渗透特性的研究

为了有效捕获和分离CO₂，提出了一种电荷与应变协同调控的气体捕获和渗透的新方法，该方法具有可逆性和动力学可控的优点。采用分子动力学(MD)模拟和基于第一性原理密度泛函理论(DFT)计算，分析了不同电荷密度和拉伸应变控制下的多孔g-C₉N₇纳米片对CO₂捕获和渗透的影响规律。通过电荷调控策略，CO₂分子渗透率高达5.94×107 GPU(即0.019 899 mol/(s·Pa·m2))。另外，CO₂渗透率随拉伸应变率的增加而增大，拉伸应变率为7.5%的g-C₉N₇薄膜的最大渗透率为3.61×107 GPU(即0.012 094 mol/(s ·Pa ·m2))。在此基础上，采用负电荷与应变工程相结合的方法研究二者的协同效应，在负电荷为1 e、拉伸应变率为3.0%的条件下，CO₂渗透率达到3.18×107 GPU(即0.001 065 mol/(s ·Pa ·m2))。此时CO₂渗透率是仅施加1 e时CO₂渗透率的9倍，是仅添加3.0%应变率时CO₂渗透率的8倍。研究结果为开发具有CO₂捕获和分离高度可控的高性能材料提供了理论指导。

Characteristics of CO2 Adsorption and Permeability of Porous Carbon-Nitrogen Membranes Coupling-regulated by Charge and Strain

In order to promote the development of new materials and technologies to effectively capture and separate CO₂, a new charge-and strain-controlled gas capture and permeation method is proposed, which has the advantages of reversibility and controllable dynamics. The molecular dynamics (MD) simulation and first-principles density function (DFT) calculation are used to analyze the effects of CO₂ capture and penetration on porous g-C₉N₇ nanosheets with different charge densities and stress controls. Through charge regulation, the molecular permeance of CO₂ can reach 5.94×107 GPU (0.019 899 mol/(s·Pa·m2)). Under tensile strain conditions, the CO₂ permeance increases with the increase of tensile strain, and the maximum permeance of 7.5% tensile strain rate g-C₉N₇ membrane is 3.61×107 GPU(0.012 094 mol/(s ·Pa ·m2)). More interestingly, a feasible way is explored to combine negative charge with strain engineering to study synergistic effects. When the negative charge is 1 e and the tensile strain rate is 3.0%, the CO₂ permeability reaches 3.18×107 GPU(0.001 065 mol/(s ·Pa ·m2)), which is 9 times of that when only 1 e is added and 8 times of that when only 3.0% is added. These results provide useful guidance for the development of advanced materials with highly controllable CO₂ capture and separation properties.