电荷与应变协同调控g-C_(9)N_(7)膜对CO_(2)吸附和渗透特性的研究

Characteristics of CO_(2) Adsorption and Permeability of Porous Carbon-Nitrogen Membranes Coupling-regulated by Charge and Strain

为了有效捕获和分离CO_(2),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-C_(9)N_(7)纳米片对CO_(2)捕获和渗透的影响规律。通过电荷调控策略,CO_(2)分子渗透率高达5.94×10^(7) GPU(即0.019899 mol/(s·Pa·m^(2)))。另外,CO_(2)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-C_(9)N_(7)薄膜的最大渗透率为3.61×10^(7) GPU(即0.012094 mol/(s·Pa·m^(2)))。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,CO_(2)渗透率达到3.18×10^(7) GPU(即0.001065 mol/(s·Pa·m^(2)))。此时CO_(2)渗透率是仅施加1 e时CO_(2)渗透率的9倍,是仅添加3.0%应变率时CO_(2)渗透率的8倍。研究结果为开发具有CO_(2)捕获和分离高度可控的高性能材料提供了理论指导。

In order to promote the development of new materials and technologies to effectively capture and separate CO_(2),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 CO_(2) capture and penetration on porous g-C_(9)N_(7) nanosheets with different charge densities and stress controls.Through charge regulation,the molecular permeance of CO_(2) can reach 5.94×10^(7) GPU(0.019899 mol/(s·Pa·m^(2))).Under tensile strain conditions,the CO_(2) permeance increases with the increase of tensile strain,and the maximum permeance of 7.5%tensile strain rate g-C_(9)N_(7) membrane is 3.61×10^(7) GPU(0.012094 mol/(s·Pa·m^(2))).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 CO_(2) permeability reaches 3.18×10^(7) GPU(0.001065 mol/(s·Pa·m^(2))),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 CO_(2) capture and separation properties.