Tungsten Oxide

The contradiction between the increase of organic nitrides and sulfides in oil and the heavy crude oil. The strict environmental protection regulations are becoming more and more serious, so it is necessary to conduct deep hydrofining for oil products. The research shows that although the traditional molybdenum sulfide based catalyst is effective in hydrotreating process, it is far from meeting the requirements of deep hydrodesulfurization. The current approach is to retrofit existing catalysts and find new catalysts that can be used to meet the need for deep hydrotreating of crude oils. In 1990s, the synthesis and performance of tungsten nitride hydrodesulfurization catalyst have been reported abroad, and the structure and desulfurization performance of P, Ni, W catalyst with phosphorus as auxiliary agent have been studied. However, the research on tungsten phosphide seems to be few. Therefore, the Chinese scholars also try to use tungsten phosphide for hydrodesulfurization test, so a...

With the continuous strengthening of human environmental awareness, the quality of living environment has aroused widespread concern. All countries have formulated strict standards for the quality indicators of sulfur, nitrogen and other harmful substances in petroleum products. The clean production process and green products have become the mainstream trend in the development of petroleum refining and chemical production. In recent years, the transition metal nitrides hydrotreating catalyst has become a hot topic in the field of new catalysts because of its excellent deep hydrodesulfurization, denitrification activity and selectivity. Some scholars believe that the current research on oil desulfurization catalyst is too focused on the cobalt molybdenum series earlier, and has excellent mechanical and thermal stability and anti poisoning characteristics of nickel tungsten catalysts study less, but in fact, the nickel tungsten nitrogen catalyst has more potential applications.  By u...

Monolayer tungsten disulfide is a kind of nano material with layered structure, it has better temperature stability than monolayer disulfide. It has attracted much attention in recent years because of its better optical and electrical properties, in the semiconductor field such as transistors, tungsten disulfide is an indirect bandgap semiconductor, forbidden band width is  2.0eV, it has more space than the application of graphene in the field of electronic tube. At present, the most important methods to prepare monolayer tungsten disulfide in China are three methods: RF sputtering, reactive magnetron sputtering and chemical deposition. In recent years, the research on the preparation of two-dimensional TMDCs by CVD(chemical vapor deposition) method is mainly focused on molybdenum disulfide, because MoS 2  requires lower temperature and it is easy to control the growth process, tungsten disulfide seems much more complex. There are two main ways to prepare tungsten disulfide fi...

Two dimensional transition metal chalcogenide (TMDCs) is considered as a potential star material for future applications of electronic devices because of its graphene like structure. The current research more semiconductor materials are tungsten disulfide WS 2 , molybdenum disulfide MoS 2 , MoSe 2  molybdenum selenide, WSe 2  tungsten selenide and so on. Among them, WS 2  has the most promising application in electronic devices because of its bipolar electron transport properties. Single layer two W is a kind of layered material similar to graphite with a layer spacing of 0.7 nm. WS 2  is an important photoelectric material. When WS 2  is changed from bulk material to single layer, the material changes from indirect bandgap to direct band gap semiconductor, and the band gap will change from 1.3eV to 2.0eV, which makes the monolayer tungsten disulfide thin films have important potential applications in photoelectric detectors and solar cells. Monolayers of tung...

Rare earth ions are rich in energy levels, their luminescence wavelengths can change from ultraviolet to infrared. They are often used as luminescent centers in luminescent materials. Metal tungstate is a kind of important inorganic functional materials, including tungsten ore stone structure of zinc tungstate (ZnWO 4 ) is a self luminous material type. WO 4 2-  itself has self excitation fluorescence, emits blue green light under ultraviolet irradiation, and can effectively transfer energy to rare earth ions. Therefore, it is widely concerned that in the chemical industry, the self luminescent tungstate doped rare earth element is the most effective LED light source acquisition scheme to change its fluorescence color. At present, the synthesis methods of rare earth doped ZnWO 4  are sol gel method, combustion method, hydrothermal method and microemulsion method. Hydrothermal synthesis is a commonly used method for the synthesis of green phosphors ZnWO 4 :Tb 3+ . In the proces...

Whisker is a kind of fiber which grows in single crystal form under artificial control. Whisker's  diameter is very small (micron order of magnitude), no defects in the usual materials (grain boundaries, dislocations, voids, etc.).  Its atomic arrangement is highly ordered, so its intensity is close to the theoretical value of the complete crystal. Because the whisker reinforced composites have the potential of high strength, the research and development of whiskers have been paid much attention to. Zinc tungstate whisker is mainly used in metal matrix composites, and it is a key high-tech material. It has been widely used in ceramic cutting tools, space shuttles, automobile parts, chemical industry, machinery and energy production.  Zinc tungstate has a better scintillation performance than the currently widely used scintillation crystal, but also has the characteristics of not deliquescence and low price, and is a very promising scintillation crystal. The size of zinc ...

Fullerene is the third allotrope of elemental carbon was found by a carbon, any elements in spherical, oval shaped structure of the material existence. In the field of lubricants, tungsten disulfide is a typical layered structure, easy to slip away, it is widely used in the field of lubricants, but tungsten disulfide due to its crystal edge of the unsaturated suspension bond with chemical activity, easy in the friction process oxidized, the tribological properties of graphene are greatly reduced, especially in humid atmosphere. Graphene has good chemical stability, so it is applied in practice, people tend to be tungsten disulfide and graphene compound made of lubricants, but some scholars use inorganic fullerene C 60  instead of graphene, and get better results. The inorganic fullerene structure eliminates the dangling bonds on the edge and has higher chemical inertness. The hollow cage structure can provide higher elasticity and increase the resilience in the load range, in ord...