First-Principles Study of the Gas Sensing of Benzene and Formaldehyde by Ag₂O- and CuO-Modified MoSe₂ Nanosheets

Abstract

C6H6 and HCHO are two types of hazardous indoor gasses that seriously threaten human health. Based on first-principles calculations, Ag2O- and CuO-modified MoSe2 nanosheets were selected as gas-sensing materials to study their adsorption and sensitivity to C6H6 and HCHO. The calculation results showed that Ag2O and CuO exhibit a stable modification structure on the MoSe2 nanosheets, which improves the gas adsorption activity of the MoSe2 surface. The adsorption structure, adsorption energy, charge transfer, energy band, and density of states were analyzed based on density functional theory. Gas molecules form stable structures on the surface of Ag2O–MoSe2 nanosheets by chemical adsorption and CuO–MoSe2 nanosheets by physical adsorption. The adsorption capacity of both Ag2O and CuO-modified MoSe2 nanosheets is HCHO > C6H6, and both gas adsorption processes are exothermic and occur spontaneously. In contrast, the gas adsorption on Ag2O–MoSe2 nanosheets is more stable than that on CuO–MoSe2 nanosheets.

Physisorption Behaviors of Organochlorine Pesticides on the InP3 Monolayer from Theoretical Insight

“…Furthermore, the interactions between four organochlorine pesticide molecules and the InP 3 surface are analyzed with the highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO) of molecule orbital theory. , …”

“…Furthermore, the interactions between four organochlorine pesticide molecules and the InP 3 surface are analyzed with the highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO) of molecule orbital theory. 42,43 The energy difference between HOMO and LUMO is defined as an energy gap (E g ), which is beneficial for the understanding of change in conductivity before and after pesticide molecule adsorption. Figure 3 , where E g ad and E g pure represent the energy gap of four adsorption systems and pure InP 3 substrate.…”

Adsorption and Sensing Performance of Vented Gases from Lithium-Ion Batteries on Transition-Metal-Doped GeTe Nanosheets: A DFT Investigation

“…A more negative E ad value shows that the substrate has a greater capacity to adsorb the gas. In addition, the most stable gas adsorption structure can be obtained by analyzing the adsorption structure and E ad . The E ad of each gas adsorption system was calculated using eq . , E ad = E suf / gas − E suf − E gas where E suf/gas is the total energy of the system after gas adsorption on pristine or TM-doped GeTe, E suf represents the energy of the pristine or TM-doped GeTe, and E gas is the energy of the gas molecules.…”

Defect and interface/surface engineering synergistically modulated electron transfer and nonlinear absorption properties in MoX2 (X = Se, S, Te)@ZnO heterojunction

“…According to their structural compatibility and van der Waals interaction, 2D MX 2 layers can be fabricated into a variety of transverse and longitudinal heterostructures, 20 where the creation of a heterojunction is an effective means to the improve semiconductor performance of materials. Thus far, various heterojunction composites based on modified TMDs have been reported, including metal@TMDs (Ag, Cu, Au), [21][22][23] metallic-compound@TMD composites (CuO, ZnO, Co 3 O 4 , TiO 2 ), [24][25][26][27][28][29] nonmetal@TMDs (graphene) 30 and TMD@TMD composites (MoS 2 , WSe 2 ). 31,32 Among them, combining TMDs with metallic compounds to construct heterojunctions has become a popular method to change their structure and performance defects.…”