两性离子
化学
水溶液
从头算
计算化学
甘氨酸
动能
质子
吸收(声学)
速率决定步骤
分子动力学
反应速率
反应机理
限制
化学物理
氨基酸
物理化学
分子
有机化学
材料科学
催化作用
物理
机械工程
生物化学
量子力学
工程类
复合材料
作者
Xiaochu Ma,Vyacheslav S. Bryantsev,Santanu Roy
标识
DOI:10.1016/j.xcrp.2023.101642
摘要
Aqueous amino acids are promising absorbents for direct air capture (DAC) of CO2. Herein, we investigate the possibility of kinetic control of CO2 absorption with aqueous anionic glycine (GLY−) by employing extensive ab initio molecular dynamics simulations, free energy analysis, and reaction rate theory. We find that first GLY− binds to CO2 by overcoming a barrier (7.4 kcal/mol) to form a zwitterion intermediate, which then releases a proton by overcoming a similar barrier. Despite the similarity in the barrier, zwitterion formation appears to be the rate-limiting step because it is two orders of magnitude slower (microseconds) than the proton release step. This is predominantly due to stronger nonequilibrium solvent effects for the former that cause many barrier-recrossing events and effectively slow down the reaction rate. Such a detailed fundamental understanding of the amino acid-based CO2-absorption mechanism and rates is key to improving the kinetic efficiency of DAC technology.
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