  The process of environmental oxidation is pivotal in determining the physical
and chemical properties of two-dimensional (2D) materials. Its impact holds
great significance for the practical application of these materials in
nanoscale devices functioning under ambient conditions. This study delves into
the influence of O2 and O3 exposure on the structural and electronic
characteristics of the C2N monolayer, focusing on the kinetics of adsorption
and dissociation reactions. Employing first-principles density functional
theory calculations alongside climbing image nudged elastic band calculations,
we observe that the C2N monolayer exhibits resistance to oxidation and
ozonation, evidenced by energy barriers of 0.05 eV and 0.56 eV, respectively.
These processes are accompanied by the formation of epoxide (C-O-C) groups.
Furthermore, the dissociation mechanism involves charge transfers from the
monolayer to the molecules. Notably, the dissociated configurations demonstrate
higher bandgaps compared to the pristine C2N monolayer, attributed to robust
C-O hybridization. These findings suggest the robustness of C2N monolayers
against oxygen/ozone exposures, ensuring stability for devices incorporating
these materials.
