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Effects of Vacancy-Defected, Dopant and the Adsorption of Water upon Mn_{2}O_{3} and Mn_{3}O_{4} (001) Surfaces: A First-Principles Study

100%

Mansouri M.

Acta Physica Polonica A

2018

vol. 133

issue 5

1178-1185

In this study, a first-principles study using the spin-polarized density functional theory approach within corrected functional was carried out to investigate the electronic features of manganese oxide surfaces under three situations of (a) cation vacancy, (b) intercalation of multi- and univalent ions, and (c) adsorption of a water molecule upon the surface as catalytic performance. The possibility of obtaining the significant absolute magnetic momentum phases from native defects in orthorhombic structures of Mn_{2}O_{3} and Mn_{3}O_{4} (001) surface is explored, whereas Mn vacancy provides a transition from the insulating phase into a metal-like nature and modifies the electronic transport. Moreover, bandgap engineering via impurity intercalation has been explored. Ca^{+2} and Al^{+3} intercalations have manifested substantial attributes and explain the experimental results as efficient conducting system and catalytic activity. Furthermore, the adsorption of one water molecule and the most stable configuration, adsorption energies and electronic properties were thoroughly discussed. Accordingly, it was explored that H_{2}O: Mn_{2}O_{3} and Mn_{3}O_{4} exhibit suitable parameters as efficient catalytic synthesis.

Ab Initio Investigation on the Effect of Transition Metals Doping and Vacancies in WO₃

63%

Mansouri M., Mahmoodi T.

Acta Physica Polonica A

2016

vol. 129

issue 1

8-14

We did a density functional theory spin-polarized calculation based on pseudopotential method on the effect of both vacancy and substitutional impurity in the tungsten tri-oxide lattice. We investigated oxygen and tungsten vacancies and for substitutional dopants we used palladium (Pd), platinum (Pt) and gold (Au) atoms with the formula A_xW_{1-x}O₃ and x=0.125, 0.25, 0.375, 0.5. We obtained electronic band structure, density of states and magnetization of defected and doped WO₃. The results show that in the presence of tungsten vacancy, WO₃ acts as a semiconductor with an indirect band gap while oxygen vacancy induces a metallic behavior for WO₃. Besides, for Pt and Pd the location of trap states lead to photoexcited hole capturing, which can improve photocurrent but for Au dopant, the trap states occur in the middle of the band gap as active recombination centers. Furthermore, both kind of vacancies and Pt dopant can induce magnetization in all values of x, while Pd and Au are less efficient in inducing magnetization.

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2 Acta Physica Polonica A

1 2018

1 2016

2 Mansouri M.

1 Mahmoodi T.

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Effects of Vacancy-Defected, Dopant and the Adsorption of Water upon Mn_{2}O_{3} and Mn_{3}O_{4} (001) Surfaces: A First-Principles Study

Ab Initio Investigation on the Effect of Transition Metals Doping and Vacancies in WO₃