TY - JOUR
T1 - Sodium Electron Solvation and Reactivity at Water Surface
AU - Dong , Hui
AU - Bu , Yuxiang
JO - Communications in Computational Chemistry
VL - 1
SP - 13
EP - 23
PY - 2025
DA - 2025/04
SN - 7
DO - http://doi.org/10.4208/cicc.2025.26.01
UR - https://global-sci.org/intro/article_detail/cicc/24044.html
KW - Interface electron solvation, solvated electron, reactivity, proton-coupled electron transfer, $ab$ initio molecular dynamics simulation.
AB - <p style="text-align: justify;">Interfacial solvated electrons (${\rm e}^-_{{\rm sol}}s$) possess
profound application values in physics,
chemistry, and materials, thus attracting
ever-growing attention. Although previous
studies have unequivocally corroborated the
involvement of <span style="text-align: justify; text-wrap-mode: wrap;">${\rm e}^-_{{\rm sol}}s$</span> in the reaction of alkali
metals with water, the mechanism has not been
thoroughly revealed. Here, we simulate the
solvation and ionization process of a single Na
or a metallic ${\rm Na}_8$ cluster at the vacuum-liquid
interface by the hybrid functional-based $ab$ initio molecular dynamics (AIMD) method,
especially to elucidate the interfacial electron
dynamics behavior. Results show that the
electron donated by Na or ${\rm Na}_8$ is partially solvated at the interface, a process driven by both the ${\rm Na}^+$ interaction with the electron and its stabilization in water, which promotes electron redistribution,
delocalization, and activation. Additionally, solvation increases the $H_2O$ population near HOMO and
on unoccupied orbitals, promoting $H_2O$ reorganization and electron transfer. In aqueous solutions, Na
is highly ionized and generates a unique pre-solvated electron (${\rm e}^-_{{\rm pre}}$). ${\rm Na}_8$ cluster, on the other hand, is
partially solvated through bottom active O-coordinating sites at the interface, polarizes internally, and
produces a pre-solvated dielectron (${\rm e}^{2-}_{2 \ {\rm pre}}$), which is followed by $H_2O$ reorganization near the surface
and the subsequent hydrogen evolution reaction by proton-coupled electron transfer. Surrounding $H_2O$ molecules form multiple Na-O bonds with the remaining ${\rm Na}^{2+}_8$ to compensate for ${\rm e}^{2-}_{2 \ {\rm pre}}$ loss. Our
work displays the microscopic dynamics mechanism of Na and $H_2O$ reaction by AIMD simulation and
provides evidence for the participation of ${\rm e}^-_{{\rm pre}}s$ in the hydrogen evolution reaction, which deepens our
attention and understanding of redox reactions involving ${\rm e}^-_{{\rm sol}}s.$</p>