Metallic Contact between MoS2 and Ni via Au Nanoglue.

A critical factor for electronics based on inorganic layered crystals stems from the electrical contact mode between the semiconducting crystals and the metal counterparts in the electric circuit. Here, a materials tailoring strategy via nanocomposite decoration is carried out to reach metallic contact between MoS2 matrix and transition metal nanoparticles. Nickel nanoparticles (NiNPs) are successfully joined to the sides of a layered MoS2 crystal through gold nanobuffers, forming semiconducting and magnetic NiNPs@MoS2 complexes. The intrinsic semiconducting property of MoS2 remains unchanged, and it can be lowered to only few layers. Chemical bonding of the Ni to the MoS2 host is verified by synchrotron radiation based photoemission electron microscopy, and further proved by first-principles calculations. Following the system's band alignment, new electron migration channels between metal and the semiconducting side contribute to the metallic contact mechanism, while semiconductor-metal heterojunctions enhance the photocatalytic ability.

A DFT study of the effect of SO4 groups on the properties of TiO2 nanoparticles.

We present a study of the optical, electronic, and structural properties of TiO2 anatase-structured nanoparticles upon adsorption of SO4 groups, which are always present on the surface of the particles during the sulfate manufacturing method. Structural and electronic properties were studied using the density functional theory method (DFT), and optical properties were obtained by time-dependent DFT. It was found that SO4 groups alter both the geometric and electronic structure of TiO2 nanoparticles and change the photoabsorption characteristics. In particular, we find that η2-O2 type O-O moieties are formed due to the adsorption of 3 and 4SO4 groups.

Surface Morphology and Sulfur Reduction Pathways of MoS2 Mo Edges of the Monolayer and (100) and (103) Surfaces by Molecular Hydrogen: A DFT Study.

We have performed a density functional theory study of the MoS2 monolayer and the MoS2 (100) and (103) surfaces in relation to the early stages of the hydrodesulfurization reaction. In many X-ray diffraction (XRD) results, the (103) surface exhibits a higher peak than the (100) surface, yet one of the most frequently occurring surface has not been studied extensively. By analyzing experimental studies, we conclude that the (103) surface of MoS2 is the most frequently occurring edge surface when the sample size is thicker than ∼10-15 nm. Herein, we report the first comparison of reaction paths for the formation of a sulfur vacancy on the (103) surface of MoS2, monolayer, and (100) surface of MoS2. The reason for the occurence of the (103) surface in the XRD patterns has been established. We point out the similarity in the reaction barriers for the monolayer and (100) and (103) surfaces and discuss the reason for it. Moreover, we found a more energetically favorable step in the reaction pathway for the formation of a sulfur vacancy, which allowed us to refine the previously established pathway.