Prediction of a highly sensitive molecule sensor for SO<i><sub>x</sub></i> detection based on TiO<sub>2</sub>/MoS<sub>2</sub> nanocomposites: a DFT study

2016-10-15T08:21:55Z (GMT) by Amirali Abbasi Jaber Jahanbin Sardroodi
<p>First principles calculations within density functional theory have been carried out to investigate the adsorptions of SO<i><sub>x</sub></i> (<i>x</i> = 1, 2) molecules on TiO<sub>2</sub>/MoS<sub>2</sub> nanocomposites in order to fully discover the gas sensing capabilities of TiO<sub>2</sub>/MoS<sub>2</sub> composite systems. The van der Waals interactions were included to obtain the most stable geometrical structures of TiO<sub>2</sub>/MoS<sub>2</sub> nanocomposites with adsorbed SO<i><sub>x</sub></i> molecules. SO<i><sub>x</sub></i> molecules preferentially interact with the doped nitrogen and fivefold coordinated titanium sites of the TiO<sub>2</sub> anatase nanoparticles because of their higher activities in comparison with the other sites. The results presented include structural parameters such as bond lengths and bond angles and energetics of the systems such as adsorption energies. The variation of electronic structures are discussed in view of the density of states and molecular orbitals of the SO<i><sub>x</sub></i> molecules adsorbed on the nanocomposites. The results show that the adsorption of the SO<i><sub>x</sub></i> molecule on the N-doped TiO<sub>2</sub>/MoS<sub>2</sub> nanocomposite is energetically more favorable than the adsorption on the undoped one, implying that the nitrogen doping helps to strengthen the interaction of SO<i><sub>x</sub></i> molecules with TiO<sub>2</sub>/MoS<sub>2</sub> nanocomposites. These calculated results thus provide a theoretical basis for the potential applications of TiO<sub>2</sub>/MoS<sub>2</sub> nanocomposites in the removal and sensing of harmful SO<i><sub>x</sub></i> molecules.</p>