Cis-Dioxomolybdenum (VI) Complexes with N-donor Macrocyclic Ligands

The preparation of one monomeric [MoO2(L)](acac)2 having a Schiff base came by condensation of di-2-furanylethanedione with 2,3-diaminotoluene and 4 different complexes having formulation [MoO2(ML)](acac)2, from the result of [MoO2(L)](acac)2 with 1,3-diketones will be described with this paper. The preparation of each of these five MoO2 (VI) complexes was symbolized by thermal studies, UV-Vis, IR, elemental analyses, NMR, and molar conductance. The coordination number of molybdenum metal will be six. All 5 complexes of MoO2(VI) have a geometry of distorted octahedral arrangement. The octahedral arrangement of Mo-metal in prepared complexes is finished by 2 oxo O-atoms and 4 N-atoms from the synthesized ligand. All of the synthesized complexes demonstrated moderate action against S. aureus and S. typhi. The progression inside the antibacterial task being defined on the thought of chelation speculation.

Recent Advances in Molybdenum-Based Materials for Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries as power supply systems possessing a theoretical energy density of as high as 2600 Wh kg−1 are considered promising alternatives toward the currently used lithium-ion batteries (LIBs). However, the insulation characteristic and huge volume change of sulfur, the generation of dissolvable lithium polysulfides (LiPSs) during charge/discharge, and the uncontrollable dendrite formation of Li metal anodes render Li-S batteries serious cycling issues with rapid capacity decay. To address these challenges, extensive efforts are devoted to designing cathode/anode hosts and/or modifying separators by incorporating functional materials with the features of improved conductivity, lithiophilic, physical/chemical capture ability toward LiPSs, and/or efficient catalytic conversion of LiPSs. Among all candidates, molybdenum-based (Mo-based) materials are highly preferred for their tunable crystal structure, adjustable composition, variable valence of Mo centers, and strong interactions with soluble LiPSs. Herein, the latest advances in design and application of Mo-based materials for Li-S batteries are comprehensively reviewed, covering molybdenum oxides, molybdenum dichalcogenides, molybdenum nitrides, molybdenum carbides, molybdenum phosphides, and molybdenum metal. In the end, the existing challenges in this research field are elaborately discussed.

Resistance to Molten Superalloy at 1550 °C for Molybdenum Metal Core with a Silica/Silicide Coating

This work designs a silica (SiO2) layer on a molybdenum metal core to provide new insights on the corrosion resistance of the silica/silicide coating in the Ni-based superalloy. The molybdenum substrate coated with MoSi2 by pack cementation was pre-oxidized to fabricate a cristobalite scale on the surface and the preoxidation specimens were chosen to examine the corrosion-resistant property by using a DSM11 superalloy at 1550 °C. In order to prepare a cristobalite layer, the microstructure evolution of a 40- µm MoSi2 coating with the different oxidation parameters (temperature and time) was investigated. After casting test, the different casting results showed that the silicide layer was dissolved in the molten superalloy. However, the molybdenum matrix was found to be protected by the cristobalite layer, as well as accompanied by the cristobalite layer partially destroyed at the core/superalloy interfaces. Furthermore, the reason for the destruction of cristobalite layer was analyzed. The failure mechanism of the cristobalite layer was proposed during the cast process.

Characterization and Synthesis of Molybdenum Metal Precursors for Hydrocracking Reaction of Vacuum Residues

In this study, Molybdenum precursors were synthesized with Triphenylphosphine, 1,2-Bis(diphenylphosphino)ethane, Pyridine, 2,2-Bipyridine as a ligands. The molybdenum precursors was used for Hydrocraking reaction of Vacuum Residue (VR). Hydrocracking reactions were carried out under the 430 °C and H2 pressure of 80 bar in an 100 ml high pressure reactor. New Molybdenum precursors were tested and their activities were compared with Mo-octoate. The Molybdeum-Phosphine precursor showed the best performances, high yield and low coke contents (below 0,5 wt%), in of hydrocracking for VR. To characterize the physicochemical properties of Moprecursor catalyst, various characterization techniques (NMR, XPS) were carried out. We confirmed that cokes in the reactor were contained the P atoms derived from ligand of Mo-precursor after hydrocracking of VR.

Effect of Nano ZrO2 Additions on the Mechanical Properties of Ti-12Mo Composite by Powder Metallurgy Route

Ti-12Mo/ZrO2 nanocomposites are fabricated using the powder metallurgy technique for the potential of aerospace applications. Titanium-12 wt. % molybdenum metal matrix composite containing various percentages of ZrO2 (5, 10, and 15 wt. %) are prepared. The phase composition and microstructure of Ti-12Mo/ZrO2 powder, as well as the consolidated composites), are investigated by both X-ray diffraction and scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS) respectively. All the consolidated composites are characterized by measuring the density, Vickers hardness, and wear rate. XRD refers to no new phase are formed between Ti, Mo, and ZrO2 during the sintering process. Also, a good microstructure is achieved. Results indicated that the density of the sintered composites is increased with increasing ZrO2 percent up to 5 wt. %. On the other hand, the highest hardness and highest wear resistance are achieved for 5 wt. % ZrO2 sample. The present work demonstrated that Ti-12Mo/ZrO2 composites have a high potential for aerospace applications.