A study of single-layer and restacked MoS₂by X-ray diffraction and X-ray absorption spectroscopy

A simple electrochemical route to metallic phase trilayer MoS2: evaluation as electrocatalysts and supercapacitors

“…15,35 In the case of 1T phase in particular, the excess negative charge formed due to the electron donation from lithium is stabilised by adsorption of water molecules on both sides of the nanosheets which then increases the overall thickness of the flake. 11,17 The presence of adsorbed water layers on 1T-MoS 2 is supported using powder X-dray diffraction data which shows a diffraction peak at 2θ ≈8 ° that was not present in bulk MoS 2 ( Figure S2) and the corresponding d-spacing is 1.1 nm. Previous work attributed this process to the adsorption of bilayer water molecules between the adjacent layers of MoS 2 nanosheets.…”

“…Previous work attributed this process to the adsorption of bilayer water molecules between the adjacent layers of MoS 2 nanosheets. 17 A broad diffraction peak also seen at 14.5° (002) with interlayer distance of 6.1 nm, and no other peaks were observed unlike in bulk MoS 2 . We should also note that a few flakes showed a was estimated as 0.26 nm 17 .…”

“…13,16 Then, the resulting Li intercalated bulk MoS 2 is immersed in water and sonicated to exfoliate it down to monolayer to few layer thick MoS 2 nanosheets with dimensions typically of submicron lateral size. 15,17,18 Whilst this method is attractive due its high yield of monolayer MoS 2 sheets, it also has some major drawbacks; the process requires a long lithiation time (2-3 days) under reflux (100 °C) conditions. 13 19 Furthermore, organolithium compounds are highly pyrophoric so must be handled away from oxygen and moisture, restricting the reaction to a glove box.…”

Model oxide supported MoS2 HDS catalysts: structure and surface properties

“…In fact, as the XRD peak broadening depends on the coherent scattering domains, it is possible to determine the crystallite dimensions of the MoS 2 slabs in the c-axis direction by applying the Sherrer's equation (D 002 =0.76·λ/β 002 ·cosθ, where λ is the wavelength of the X-Rays, β is the angular full-width-at-half-height FWHM and θ is the diffraction angle), 31 to the (002) XRD diffraction line (see inset of A mean value of about 4 nm was obtained by considering an interlayer distance of 6.17 Å, which indicates a staking number of ≈ 6 layers. As the presence of single MoS 2 layers and the defectivity (such as imperfect stacking and bending of layers) affects the scattering profile and the (002) XRD diffraction peak as well, 5,18,[31][32][33][34][35] the evaluation of the average number of slabs following this method is quite approximate and overestimated, as already observed for well dispersed MoS 2 catalysts. 5 The presence of heterogeneous MoS 2 particles characterized by an average staking value of about 6 layers and the high heterogeneity emerging from the analysis of the 2θ ≈ 30°÷50° range will be substantially confirmed by the Raman and TEM analyses (see below).…”

Optimizing Hybridization of 1T and 2H Phases in MoS2Monolayers to Improve Capacitances of Supercapacitors

“…The thickness of the NSs was measured by atomic force microscopy (AFM) to be 0.8 nm (Figure 2 (105) peaks are no longer seen in the exfoliated product, implying the restacking of the exfoliated monolayer MoS 2 NSs. [16,17] Moreover, a new diffraction peak at 7.6°( shown in the inset) was induced by the restacking of monolayers, whose spacing of 1.376 nm is larger than that in the pristine powder (0.615 nm). The (002) peak gradually shifted towards lower angles and became broad indicating the expansion of the interlayer distance and the relatively small size of MoS 2 NSs.…”