Nitride molybdenum

In most of the nonmetaHurgical uses of molybdenum compounds the metal is coordinated by oxygen or sulfur ligands. Molybdenum nitrides, carbides, and sihcides are, however, coming under increasing study for various appHcations. Roughly 75% of all molybdenum compounds are used as catalysts in the petroleum and chemicals industries. 

Systematic assessment of alumina-supported cobalt-molybdenum nitride catalyst Relationship between nitriding conditions, innate properties and CO hydrogenation activity... 

Song, J., et al., Synergistic effect of molybdenum nitride and carbon nanotubes on electrocatalysis for dye-sensitized solar cells. Journal of Materials Chemistry, 2012. 22(38) p. 20580-20585. 

The reasoning which led the author to make this first shot in the dark regarding the usefulness of combinations of solid compounds as ammonia catalysts was as follows If we assume that a labile iron nitride is an interminate in the catalytic ammonia synthesis, every addition to the iron which favors the formation of the iron nitride ought to be of advantage. In other words, the hypothesis was used that surface catalysis acts via the formation of intermediate compounds between the catalyst and one or more of the reactants. An experimental support for this theory was the fact that a stepwise synthesis via the formation and successive hydrogen reduction of nitrides had been carried out with calcium nitrides (Haber), and cerium nitrides (Lipski). Later, the author found molybdenum nitride as being the best intermediate for such a stepwise synthesis. 

Table 1 The influence of ammonolysis parameters on the surface area of molybdenum nitride adapted from reference 18...

Molybdenum nitride itself has been dispersed on platinum clusters dispersed in EMT zeolite. In this study, coverage of platinum particles by molybdenum deposition was investigated and was reported to suppress the activity for benzene hydrogenation and enhance the heptane conversion. With respect to bare Pt for heptane conversion, the aromatisation activity was reduced, whereas isomerisation and hydrogenolysis were observed. 

The reason indium nitride UFPs cannot grow by this method is probably the low decomposition temperature (620°C) of InN. The similar consideration can be done on tungsten nitride and molybdenum nitride. The phases of W2N and Mo2N are recognized in UFPs, but no WN and MoN phases are detected their decomposition temperature is about 80()°C. 

This method has been used most widely, but it is limited to the availability of reactive nitrido complexes. The molybdenum nitrides simply abstract sulfur from episulfides (MeCHCH2S) or... 

Using MoC15 as molybdenum source it was possible to prepare molybdenum nitride in a new Mo2N modification which was isotypic with a-Mo2C molybdenum carbide 26... 

The TPR and XRD measurements showed that molybdenum nitride is formed as y-Mo2N in the 12.5% and 97.1% MoO A C catalysts nitrided with NH3 at 973 K and 1173 K. For the catalysts nitrided at 773 K, there was no formation of molybdenum nitride on the surface, but adsorbed NH3 and NHX nitrided molybdenum oxides during TPD and TPR runs. 

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