Examining O adsorption on pristine and defective popgraphene sheets: A DFT study

Popgraphene (PopG) is a two-dimensional carbon-based material with fused pentagonal and octagonal rings. Like graphene, it exhibits a metallic band gap and exceptional thermal, dynamic, and mechanical stability. Here, we theoretically study the electronic and structural properties of PopG monolayers, including their doped and vacancy-endowed versions, as O$$ adsorbers. Our findings show that pristine and vacancy-endowed PopG sheets have a comparable ability to adsorb O$$ molecules, with adsorption energies ranging from $$0.57 to $$0.59 eV (physisorption). In these cases, octagonal rings play a dominant role in the adsorption mechanism. Platinum and Silicon doping enhance the O$$ adsorption in areas close to the octagonal rings, resulting in adsorption energies ranging from $$1.13 to $$2.56 eV (chemisorption). Furthermore, we computed the recovery time for the adsorbed O$$ molecules. The results suggest that PopG/O$$ interaction in pristine and vacancy-endowed cases can change the PopG electronic properties before O$$ diffusion.

Density Functional Theory (DFT) simulations, with Van der Waals corrections (DFT-D, within the Grimme scheme), were performed to study the structural and electronic properties of PopG/O$$ systems using the DMol3 code within the Biovia Materials Studio software. The exchange and correlation functions are treated within the generalized gradient approximation (GGA) as parameterized by Perdew-Burke-Ernzerhof (PBE) functional. We used the double-zeta plus polarization (DZP) for the basis set in these cases. We also considered the BSSE correction through the counterpoise method and the nuclei-valence electron interactions by including semi-core DFT pseudopotentials.