Interaction Of Nitrogen Molecules Research Articles

Carbon dioxide adsorption on carbon nanomaterials

The adsorption of CO2 on a number of activated carbons, thermal carbon black, and oxide materials at 195 K was studied using static and dynamic techniques. The landing surface areas ω(CO2) ≈ 0.19 nm2 on thermal carbon black and the absolute values of sorption for P/P0 < 0.4 were determined. The density of adsorbed CO2 in the micropore volume was estimated at ρ(CO2) = 0.91 g/cm3. It was demonstrated that the previously found effect of a weakening of the sorption interaction of nitrogen molecules with thin-walled materials (which manifested itself in an analysis of sorption isotherms by a comparative method) was pronounced to a lesser degree for the sorption of CO2. At the same time, the presence of supermicropores in activated carbon samples resulted in overestimated values of surface areas. A dynamic method was proposed to measure the spectra of CO2 desorption at 195–260 K using a SORBI-MS system for evaluating the binding energy of sorbate molecules with the surface.

Catalytic Ammonia Synthesis over Mo Nitride/ZSM‐5

AbstractMolybdenum nitride species in HZSM‐5 are prepared by the reaction of ammonia with MoOx, which is pre‐exchanged into the channel of HZSM‐5. Both the processes of solid exchange of molybdenum oxide with the zeolite and the ammonia reaction are monitored by mass spectrometry. The Mo/N ratio of the MoNx species in the Mo nitride/HZSM‐5 is close to 2, as measured by temperature‐programmed oxidation. The MoNx species are more stable than bulk Mo2N against oxidation, due to the interaction between the molybdenum nitride species and the charged zeolite framework. The MoNx species, of which the dispersion is found to be greater than 90 %, are very active in ammonia synthesis and the catalytic activity is much more stable than that of bulk Mo2N. The reaction pressure is much more favorable to ammonia formation on the MoNx/ZSM‐5 catalyst than on bulk Mo2N. The interaction of nitrogen molecules with the inner electric field of the zeolite, at an equivalent pressure, enhances the reaction of ammonia synthesis.

Defects in Compound Semiconductors Caused by Molecular Nitrogen

The interaction of nitrogen molecules (N2) with the host lattice of compound semiconductors is investigated using first-principles density-functional calculations. In ZnO it is found that N2 causes localized states in the band gap either by forming an N2O molecule or by breaking a Zn-O bond. This mechanism contributes to the observed low nitrogen doping efficiency in ZnO. The appearance of localized states caused by N2 was also found in other semiconductors such as MgO and NaCl.

The interaction of nitrogen molecules with (4, 0) single-walled carbon nanotube: electronicand structural effects

The electronic structure and energetics of (4, 0) single-walled carbon nanotubes(CNTs) interacting with nitrogen have been studied using density-functionalcalculations. We show that the nanotubes become covered with a stable sheath ofN2 molecules. We have constructed potential energy curves which can be used for the thermodynamic analysisof N2 adsorption and desorption processes. Our results show that any analysisof the observed properties (for example thermodynamics, stability,and photoluminescence) of air-exposed CNTs needs to consider theN2 adsorbed on the CNTs.