Adsorption of Water Molecule in Graphene/MoS2 Heterostructure with Vacancy Defects in Mo Sites

Abstract

First-principle calculations based on the spin-polarized density functional theory (DFT) with vdW corrections by DFT-D2 approach have been carried out to study structural, electronic, and magnetic properties of water-adsorbed graphene/MoS2 heterostructures (system-I), and water-adsorbed graphene/MoS2 heterostructures with vacancy defects in Mo sites (systems-II). We consider vacancy defects in different Mo sites such as centre-1Mo atom vacancy defect (system-IIa), left-1Mo atom vacancy defect (system-IIb), and 2Mo atom vacancy defects (system-IIc). All the systems considered in this study are structurally stable; however, the stability of defected systems decreases with an increase in defect concentrations. The calculated binding energies of HS used in this study agree with the reported work. Electronic properties of system-I and systems-II reveal that they have metallic characteristics. Our investigation shows that system-I is nonmagnetic and systems-II are magnetic. The magnetic moment in the defected systems (system-IIa, system-IIb, and system-IIc) is developed by unpaired up and down-spins of electrons created in the orbitals of atoms due to vacancy defects in Mo atoms.

Electronic and magnetic performance of MoS2 monolayer via Tc & Nb impurities defect and water adsorption

“…We have also estimated the adsorption energy of water molecule with Tc-MoS 2 & Nb-MoS 2 by using equation (3), and found to be 2.17 eV & 2.08 eV respectively. They are comparable with the reported values of water adsorption on 2D materials [9,25,27]. Hence, water adsorbed defected materials are stable 2D materials.…”

“…This means that the properties of TMDCs can be adjusted by controlling the environment they are in [22][23][24][25]. It is interesting to study how 2D materials like TMDCs interact with various solvents, such as water, due to their atomically flat surfaces which allow for different hydrophobic and long-range interactions [26,27]. The areas around the edges and vacancies in 2D materials are highly sensitive to the adsorption of molecules, which can change the electronic and magnetic properties of the layers by distorting their arrangement [24,28].…”