Tunable redox potential of nonmetal doped monolayer MoS2: First principle calculations

Doping is an effective method to alter the electronic behavior of materials by forming new chemical bonds and bringing bond relaxation. With this aid of first principle calculations, the crystal configuration and electronic properties of monolayer MoS2 have been modulated by the nonmetal (NM) dopants (H, B, C, N, O, F, Si, P, Cl, As, Se, Br, Te and I), and the thermodynamic stability depending on the preparation conditions (Mo-rich and S-rich conditions) were discussed. Results shown that, the NM dopants substituted preferentially for S under Mo-rich condition, the electronic distribution around the dopants and the nearby Mo atoms are changed by the new formed Mo-NM bonds and bands relaxation. Compared to pristine monolayer MoS2, the NM ions with odd chemical valences enhance the oxidation potential and reduce the reduction potential of specimens, but the NM ions with even chemical valences have the opposite effects on the redox potentials. Compared to the NM ions with even chemical valences, the lone pair electrons in NM ions with odd chemical valences can extra interact with the Mo ions and reduces the Ecgm and Evgm values of specimens. It offers a simple way to design various monolayer MoS2 based catalysts in order to catalyze different materials by chose the reasonable dopants for stronger oxidation or reduction potential. (C) 2016 Elsevier B.V. All rights reserved.