Synthesis of High Surface Area Molybdenum Nitride in Mixtures of Nitrogen and Hydrogen

Molybdenum trioxide (MoO3) films, 15 µm thick, have been deposited on 50 µm thick polycrystalline titanium substrates from 250 to 500 °C via liquid spray pyrolysis. Molybdenum pentachloride (MoCl5) dissolved in methanol was used as the molybdenum source; ambient conditions provided the oxygen source. X-ray diffraction (XRD) data indicated that amorphous MoO3 films were produced at deposition temperatures below 400 °C. Randomly orientated polycrystalline MoO3 films were produced at 400 °C and higher deposition temperatures. The deposition temperature also influenced the surface area of the films and their average grain size. Subsequent conversion of the MoO3 films to high surface area (HSA) conductive films containing both γ–Mo2N and δ–MoN was accomplished via programmed reactions with anhydrous NH3 and involved the formation of MoO2 and MoOxN1−x as intermediate phases. The degree of crystallinity, surface area, and average grain size of the MoO3 films strongly influenced the average grain size and surface area of the resultant MoxN films.

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ChemInform Abstract: Synthesis of High Surface Area Molybdenum Nitride in Mixtures of Nitrogen and Hydrogen.

ChemInform ◽

10.1002/chin.199419021 ◽

2010 ◽

Vol 25 (19) ◽

pp. no-no

Author(s):

R. S. WISE ◽

E. J. MARKEL

Keyword(s):

Surface Area ◽

High Surface ◽

High Surface Area ◽

Molybdenum Nitride

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Hydrogen production by ammonia decomposition using high surface area Mo2N and Co3Mo3N catalysts

Catalysis Science & Technology ◽

10.1039/c5cy00871a ◽

2016 ◽

Vol 6 (5) ◽

pp. 1496-1506 ◽

Cited By ~ 45

Author(s):

Seetharamulu Podila ◽

Sharif F. Zaman ◽

Hafedh Driss ◽

Yahia A. Alhamed ◽

Abdulrahim A. Al-Zahrani ◽

...

Keyword(s):

Citric Acid ◽

Hydrogen Production ◽

Surface Area ◽

High Surface ◽

High Surface Area ◽

Ammonia Decomposition ◽

Molybdenum Nitride ◽

Ammonium Heptamolybdate ◽

Temperature Programmed

High surface area bulk molybdenum nitride catalysts were synthesized via temperature-programmed ammonolysis of an ammonium heptamolybdate and citric acid (CA) composite.

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Characteristics of High Surface Area Molybdenum Nitride and Its Activity for the Catalytic Decomposition of Ammonia

Catalysts ◽

10.3390/catal11020192 ◽

2021 ◽

Vol 11 (2) ◽

pp. 192

Author(s):

Seo-Hyeon Baek ◽

Kyunghee Yun ◽

Dong-Chang Kang ◽

Hyejin An ◽

Min Bum Park ◽

...

Keyword(s):

Surface Area ◽

Photoelectron Spectroscopy ◽

High Surface ◽

High Surface Area ◽

Catalytic Decomposition ◽

Molybdenum Nitride ◽

X Ray ◽

Temperature Programmed Oxidation ◽

Oxidation Reduction ◽

Temperature Programmed

High surface area (>170 m2 g−1) molybdenum nitride was prepared by the temperature-programmed nitridation of α-MoO3 with pure ammonia. The process was optimized by adjusting the experimental variables: the reaction temperature, heating rate, and molar flow rate of ammonia. The physicochemical properties of the as-formed molybdenum nitride were characterized by X-ray diffraction, N2 sorption, transmission electron microscopy, temperature-programmed oxidation/reduction, and X-ray photoelectron spectroscopy. Of the experimental variables, the nitridation temperature was found to be the most critical parameter determining the surface area of the molybdenum nitride. When the prepared molybdenum nitride was exposed to air, the specific surface area rapidly decreased because of the partial oxidation of molybdenum nitride to molybdenum oxynitride. However, the surface area recovered to 90% the initial value after H2 treatment. The catalyst with the highest degree of nitridation showed the best catalytic activity, superior to that of unmodified α-MoO3, for the decomposition of ammonia because of its high surface area.

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Structure Effects of High Surface Area Molybdenum Nitride Powders, Macrocrystals and Nanoparticles as Catalysts for Thiophene Desulfurization

MRS Proceedings ◽

10.1557/proc-549-51 ◽

1998 ◽

Vol 549 ◽

Author(s):

K. L. Roberts ◽

E. J. Markel

Keyword(s):

Surface Area ◽

Specific Activity ◽

High Surface ◽

High Surface Area ◽

Lower Surface ◽

Metal Catalysts ◽

Molybdenum Nitride ◽

Temperature Programmed ◽

Thiophene Hds ◽

N Powder

AbstractMo2N powder, macrocrystals and nanoparticles and porous Mo metal were synthesized using temperature programmed reduction of MoO3 powder and crystals with reactant feed gases consisting of NH3 N2/H2 mixtures and pure H2. The Mo-based catalysts were characterized using BET, XRD, TGA, SEM, and STM. The Mo-based catalysts were also analyzed for the hydrodesulfurization (HDS) of thiophene. The relatively lower surface area Mo2N macrocrystalline catalysts (SSA = 44 m2/g) have a greater area specific activity than that of the higher surface area Mo2N powder catalysts (SSA = 150 m2/g) for the HDS of thiophene. Mo metal catalysts have significantly lower activity for thiophene HDS than Mo 2N catalysts and the HDS selectivities of non-sulfided Mo metal catalysts are significantly different from those of Mo 2N catalysts.

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Utilization of CO2 and N2 for selective synthesis of styrene from ethylbenzene over high surface area γ-Al2O3 supported molybdenum nitride catalysts

Arabian Journal of Chemistry ◽

10.1016/j.arabjc.2018.10.008 ◽

2020 ◽

Vol 13 (1) ◽

pp. 3236-3245

Author(s):

Venkata Ramesh Babu Gurram ◽

Murali Kondeboina ◽

Siva Sankar Enumula ◽

Naveen Gajula ◽

David Raju Burri ◽

...

Keyword(s):

Surface Area ◽

High Surface ◽

High Surface Area ◽

Molybdenum Nitride ◽

Selective Synthesis

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Tenacious Mass Transfer Limitations Drive Catalytic Selectivity during Electrochemical Carbon Dioxide Reduction

10.26434/chemrxiv.7770338.v1 ◽

2019 ◽

Cited By ~ 1

Author(s):

Kailun Yang ◽

Recep Kas ◽

Wilson A. Smith

Keyword(s):

Surface Area ◽

High Surface ◽

High Surface Area ◽

Catalyst Layer ◽

Active Surface ◽

Active Surface Area ◽

High Concentration ◽

Copper Electrodes ◽

Surface Enhanced ◽

Local Current

This study evaluated the performance of the commonly used strong buffer electrolytes, i.e. phosphate buffers, during CO2 electroreduction in neutral pH conditions by using in-situ surface enhanced infrared absorption spectroscopy (SEIRAS). Unfortunately, the buffers break down a lot faster than anticipated which has serious implications on many studies in the literature such as selectivity and kinetic analysis of the electrocatalysts. Increasing electrolyte concentration, surprisingly, did not extend the potential window of the phosphate buffers due to dramatic increase in hydrogen evolution reaction. Even high concentration phosphate buffers (1 M) break down within the potentials (-1 V vs RHE) where hydrocarbons are formed on copper electrodes. We have extended the discussion to high surface area electrodes by evaluating electrodes composed of copper nanowires. We would like highlight that it is not possible to cope with high local current densities on these high surface area electrodes by using high buffer capacity solutions and the CO2 electrocatalysts are needed to be evaluated by casting thin nanoparticle films onto inert substrates as commonly employed in fuel cell reactions and up to now scarcely employed in CO2 electroreduction. In addition, we underscore that normalization of the electrocatalytic activity to the electrochemical active surface area is not the ultimate solution due to concentration gradient along the catalyst layer.This will “underestimate” the activity of high surface electrocatalyst and the degree of underestimation will depend on the thickness, porosity and morphology of the catalyst layer.

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