Strong bases behave as weak bases in nanoscale chemical environments: implication in humidity-swing CO2 air capture

Yingying HAN, Liangliang ZHU, Yutong YAO, Xiaoyang SHI, Yayun ZHANG, Hang XIAO*, Xi CHEN

*Corresponding author for this work

Research output: Journal PublicationsJournal Article (refereed)peer-review

8 Citations (Scopus)


Hydration of ions/molecules in nanometer-sized clusters or nanoscopic pores is ubiquitous and plays a key role in many chemical and physical systems. In this work, guanidine-H2O reactions with n=1-8 water molecules were systematically studied by ab initio methods. The result suggests that the reduced availability of water molecules greatly inhibits the strong base guanidine from producing OH. That is, guanidine exhibits the behavior of a weak bases in low-humidity nanoscale environments. Intriguingly, this effect is not limited to guanidine but could be applied to other strong bases. Furthermore, we demonstrate that the direction of guanidine-CO2 reactions can be controlled by changing the number of water molecules present, which in turn responds to the humidity change in air. These findings not only shed some light on unconventional chemical reactions of strong bases in atmospheric clusters and on solid porous surfaces, but also provide insights into the development of guanidine-based CO2 air-capture sorbents. © the Owner Societies 2021.
Original languageEnglish
Pages (from-to)14811-14817
Number of pages7
JournalPhysical Chemistry Chemical Physics
Issue number27
Early online date10 Jun 2021
Publication statusPublished - 21 Jul 2021
Externally publishedYes

Bibliographical note

This work was supported by the National Natural Science Foundation of China (11872302), the R&D Program of Xi’an (2020KJRC0147), the Xi’an Science and Technology Plan Project, China (2019220914SYS024CG046) and the Earth Engineering Center and Center for Advanced Materials for Energy and Environment at Columbia University.


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