Oxidation of Mo-Terminated Pit Edges in MoS<sub>2</sub> Monolayer
We employed ab initio molecular dynamics simulations to investigate the oxidation of MoS<sub>2</sub> triangular pits with oxidized zz-Mo edges. The purpose of this work is to characterize advanced stages of oxidation at high temperatures, which lead to the desorption of SO<sub>2<...
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2024
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| Summary: | We employed ab initio molecular dynamics simulations to investigate the oxidation of MoS<sub>2</sub> triangular pits with oxidized zz-Mo edges. The purpose of this work is to characterize advanced stages of oxidation at high temperatures, which lead to the desorption of SO<sub>2</sub> and the formation of oxy-thiomolybdate complexes. We first consider the energetics of the interaction of O<sub>2</sub> with the Mo atoms of the pit edge and then we calculate activation energy barriers for the initial stages of oxidation, after the dissociative adsorption of oxygen. The O<sub>2</sub> molecule chemisorbs on the Mo edge atoms with Δ<i>E</i> = −3.41 eV. The dissociation of O<sub>2</sub> has a low energy barrier of 0.71 eV which opens pathways for further oxidation processes. The ab-initio molecular dynamics simulations show that the breakage of the O–O bond of chemisorbed O<sub>2</sub> molecules on the Mo edge atoms gives rise to MoO<sub>2</sub> and MoO<sub>3</sub> moieties along the edges of the pit. As O atoms diffuse and insert into Mo–S bonds, the desorption of SO<sub>2</sub> is first observed. Further oxidation leads to the formation of surface oxy-thiomolybdate (Mo<sub>2</sub>S<sub>3</sub>O<sub>5</sub>, Mo<sub>2</sub>S<sub>2</sub>O<sub>5</sub>, Mo<sub>3</sub>S<sub>3</sub>O<sub>3</sub>, etc.) complexes which finally desorb from the surface at high temperatures. |
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