The electronic properties and water desalination performance of a photocatalytic TiO2/MoS2 nanocomposites bilayer membrane: a molecular dynamic simulation

Qusai Ibrahim; Rokhsareh Akbarzadeh; Salem Gharbia

doi:10.1007/s00894-022-05053-7

The electronic properties and water desalination performance of a photocatalytic TiO₂/MoS₂ nanocomposites bilayer membrane: a molecular dynamic simulation

J Mol Model. 2022 Feb 16;28(3):61. doi: 10.1007/s00894-022-05053-7.

Authors

Qusai Ibrahim¹, Rokhsareh Akbarzadeh², Salem Gharbia³

Affiliations

¹ School of Engineering and Design, Institue of Technology Sligo, Sligo, F91 YW50, Ireland.
² Energy, Sensors and Multifunctional Nanomaterials Research Group, Department of Chemical Sciences, Faculty of Science, University of Johannesburg, Doornfontein, 2028, South Africa.
³ Department of Civil Engineering and Construction, School of Engineering and Design, Institute of Technology, Sligo, F91 YW50, Ireland. gharbia.salem@itsligo.ie.

PMID: 35171351
DOI: 10.1007/s00894-022-05053-7

Abstract

Due to the rapid depletion of water resources, more interest is paid for the efficient desalination process in recent years. MoS₂ membrane aroused attention due to its high mechanical stability and electronic properties, which can sustain extra-large strains. In this study, the electronic properties and water desalination performance of TiO₂/MoS₂-hexagonal, and TiO₂/MoS₂-rhombohedral nanocomposites bilayer membranes were studied and simulated for the first time. The effect of TiO₂ in the performance of MoS₂ was observed in water desalination under the defined applied pressure ranging from 50 to 250 MPa with a 6.4 Å pore diameter. The membrane structure is created and optimized. The energy minimized for TiO₂ from - 19,596.4282 kcal/mol for the initial structure to - 19,605.1611 kcal/mol for the final structure. For TiO₂/MoS₂-hexagonal, the energy minimized from - 4955.54271 eV) to - 4955.62091 eV and TiO₂/MoS₂-rhombohedral from - 6042.26925 eV to - 6046.91835 eV. A molecular dynamic (MD) simulation was performed using Material Studio 2019 to study the electronic properties under 0-1 eV electric field using the CASTEP code. The results showed a better photocatalytic performance under the external electric field. The effect of external electric field significantly intensifies absorption in the visible range and achieved a high photocatalytic activity on TiO₂/MoS₂. TiO₂, TiO₂/MoS₂-hexagonal and TiO₂/MoS₂-rhombohedral nanocomposites bilayer membranes are simulated and evaluated for the water desalination using ReaxFF software. Both MoS₂ phases with TiO₂ have achieved a high salt rejection up to 97% (P-value = 0.0036, R² = 0.958), while TiO₂/MoS₂-rhombohedral achieved the highest permeability (6.0*10^-8 mm g cm^-2 s^-1 bar^-1) (P-value = 0.000296, R² = 0.972) under 250 MPa applied pressure.

Keywords: Desalination; Membrane; MoS2; Molecular dynamics; Simulation; TiO2.