Programme

P.67 -- Poster, VCTP-48

Date: Thursday, 3 August 2023

Time: 08:30 - 10:00

A DFT investigation of methanal gas absorption on monolayer MS2 (M=W, Mo)

Quang Huy Tran (1), Thi Nhan Tran (2), Thi Theu Luong (3), Viet Bac Phung (4), Van An Dinh (5)

(1) Faculty of Physics, Hanoi Pedagogical University 2, Hanoi, Vietnam; (2) Faculty of Fundamental Sciences, Hanoi University of Industry, Hanoi, Vietnam; (3) Hoa Binh University, Hanoi, Vietnam; (4) VNU Vietnam Japan University, Luu Huu Phuoc, My Dinh I, Hanoi, Vietnam; (5) Department of Precision Engineering, Graduate School of Engineering, Osaka University, Osaka, Japan

Using density functional theory (DFT), this study explores the adsorption mechanism of methanal gas on the monolayer MS2 (M=W, Mo) surface. In order to characterize the adsorption of the gas molecule and its interaction with the MS2 substrate, we utilize DFT simulations that incorporate van der Waals (vdW) interactions, conducted within the VASP framework. Using a Computational DFT-based Nanoscope tool, we determine the global minimum energy configurations and binding energies of gas molecules adsorbed on the monolayer MS2. This allows us to visualize the various binding possibilities of gas molecules on the surface of MS2. We compute the adsorption energy profiles using five functionals incorporating van der Waals interactions: revPBE-vdW, optPBE-vdW, vdW-DF2, optB88, and optB86b. The results reveal that the magnitude of adsorption energy decreases in the following order for both materials: optPBE > optB88 ≈ optB86b > revPBE > vdW-DF2. Among the two materials, methanal exhibits higher sensitivity to the MoS2 substrate, evidenced by its larger adsorption energy (253 meV) and a reduction in the bandgap (24 meV, equivalent to 1.1% decrease compared to non-adsorption). This study also includes in-depth discussions regarding the interaction between methanal and the MS2 substrate, focusing on aspects such as charge transfer, modified density of states and band structure.

Presenter: Tran Quang Huy