Adsorption of formaldehyde on transition metal doped monolayer MoS2: A DFT study

Density functional theory (DFT) calculations have been performed to investigate the electronic properties of pristine monolayer MoS2 and various transition-metal (TM) (Ni, Pt, Ti and Pd) doped MoS2 as well as the adsorption of formaldehyde on these monolayer 2D structures. It was found that the CH2O adsorption energy (0.11 eV) on monolayer MoS2 was very weak, indicating that pristine MoS2 is insensitive to formaldehyde (CH2O). However, the adsorption of CH2O on monolayer TM-MoS2 shows relatively high affinity. Thus, TM-doping can substantially improve the sensitivity towards CH2O. In order to investigate the mechanism of adsorption, the electronic properties such as molecular projected density of states and differential charge transfer were calculated. The results showed that the adsorption on Ti-doped monolayer MoS2 (1.59 eV) is very promising with the most stable adsorption. Both differential charge transfer and ab initio molecular dynamic were used to investigate the adsorption mechanism. The ab initio molecular dynamic at 500 K was performed using the Car-Parrinello method. The most stable configuration shows the highest adsorption energy and CH2O can be adsorbed even at 500 K. These suggest that Ti-doped monolayer MoS2 would be a feasible material for CH2O removal at room temperature.