Formaldehyde Molecules Adsorption on Zn Doped Monolayer MoS2: A First-Principles Calculation

Abstract

Based on the first principles of density functional theory, the adsorption behavior of H2CO on original monolayer MoS2 and Zn doped monolayer MoS2 was studied. The results show that the adsorption of H2CO on the original monolayer MoS2 is very weak, and the electronic structure of the substrate changes little after adsorption. A new kind of surface single cluster catalyst was formed after Zn doped monolayer MoS2, where the ZnMo3 small clusters made the surface have high selectivity. The adsorption behavior of H2CO on Zn doped monolayer MoS2 can be divided into two situations. When the H-end of H2CO molecule in the adsorption structure is downward, the adsorption energy is only 0.11 and 0.15 eV and the electronic structure of adsorbed substrate changes smaller. When the O-end of H2CO molecule is downward, the interaction between H2CO and the doped MoS2 is strong leading to the chemical adsorption with the adsorption energy of 0.80 and 0.98 eV. For the O-end-down structure, the adsorption obviously introduces new impurity states into the band gap or results in the redistribution of the original impurity states. All of these may lead to the change of the chemical properties of the doped MoS2 monolayer, which can be used to detect the adsorbed H2CO molecules. The results show that the introduction of appropriate dopant may be a feasible method to improve the performance of MoS2 gas sensor.

Synthesis of mono- and few-layered n-type WSe2 from solid state inorganic precursors

“…76,77 Without modifying the crystal structure or functionalizing the surface, the charge carrier nature can be shifted to ntype by applying a large positive V ds 21 or by decreasing the work function of the metal contacts. 78 Additionally, we hypothesize that Se vacancies, which are predicted to be present in CVD samples 79 , and introducing additional defect states between the Fermi level and the conduction band do not contribute as carriers in the WSe 2 . 80 This is because most of the vacancies are likely filled by oxygen, of which presence is clearly visible in the XPS measurements (see Figure 2a), since all the flakes were stored in air for several weeks before FET fabrication and then transferred using oxidizing solvents, such as water and acetone.…”

“…84,85 It is worth mentioning that in contrast, Zn-has been reported to induce p-doping in MoS 2 . 86 In general, theoretical results on Zndoped TMDs do not clearly elucidate the nature of Zn dopants as p-type, 87 semimetallic, 47,88 or ntype 89 , thus further information it is yet to be elucidated in this materials system.…”

Defected MoS2 Modified by Vanadium-Substituted Keggin-Type Polyoxometalates as Electrocatalysts for Triiodide Reduction in Dye-Sensitized Solar Cells

“…In recent years, transition metal sulfides have recently become the most promising substitutes for Pt due to their outstanding catalytic performance and abundant natural resources. , Among these materials, MoS 2 is a two-dimensional layered-structure material similar to graphene . This special structure gives MoS 2 nanosheets a larger specific surface area, greater electron transfer rate, and larger density of electronic states .…”

“…8,9 Among these materials, MoS 2 is a two-dimensional layered-structure material similar to graphene. 10 This special structure gives MoS 2 nanosheets a larger specific surface area, greater electron transfer rate, and larger density of electronic states. 11 In particular, the metastable 1T metallic phase MoS 2 nanosheets have shown excellent performance in energy applications, which makes high expectations for their electrocatalytic performance.…”