Molybdenum nitrides: a study of synthesis variables and catalytic performance in acetylene hydrogenation

Cárdenas‐Lizana, Fernando; Lamey, Daniel; Kiwi‐Minsker, Lioubov; Keane, Mark A.

doi:10.1007/s10853-018-2009-x

Cited by 24 publications

(28 citation statements)

References 59 publications

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“…However, a continuous increase in the total pore volume up to 770 • C was observed, probably because of the formation of mesopores during the partial transformation of γ-Mo 2 N to β-Mo 2 N [34]. The differentiation of γ-Mo 2 N and β-Mo 2 N by X-ray diffraction is quite difficult because of the heavy overlap of the characteristic peaks; however, the BET surface areas of γ-Mo 2 N and β-Mo 2 N fall into the range of 40-145 and 2-17 m 2 g −1 , respectively [25,35,36]. Thus, it can be reasonably speculated that the phase change of γ-Mo 2 N to β-Mo 2 N occurred at the temperatures higher than 630 • C. The rapid increase in the average pore diameter with associated reduction in the surface area and pore volume over the samples nitrided at temperatures higher than 800 • C is a result of the formation of metallic Mo particles.…”

Section: Resultsmentioning

confidence: 99%

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

et al. 2021

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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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Section: Resultsmentioning

confidence: 99%

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

et al. 2021

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“…In order to compare the nature of the atoms incorporated into the structure, a series of supported molybdenum nitride catalysts were synthesized using method A (MoN A ) or method B (MoN B ) with TiO 2 -P, TiO 2 -D, or ZrO 2 as support ( Table 2). Based on the literature dealing with the synthesis of bulk molybdenum nitride (Ghampson et al, 2012;Perret et al, 2012;Cárdenas-Lizana et al, 2018), the formation of hexagonal β-Mo 2 N is favored when using low GHSV, high heating ramp and low N 2 content in the gas stream (method A) while the opposite conditions usually generate cubic γ-Mo 2 N with high surface area (method B).…”

Section: Preparation and Characterization Of Molybdenum Nitride Catalmentioning

confidence: 99%

“…The synthesis parameters, such as gas composition, gas space velocity, heating rate, and final temperature, influence the final properties of molybdenum nitrides and carbides (Oyama, 1992;Nagai et al, 1998a;Xiao et al, 2000;Hanif et al, 2002;Mo et al, 2016;Cárdenas-Lizana et al, 2018). The presence of a support and its nature also affect the structural and catalytic properties (García Blanco et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Supported Molybdenum Carbide and Nitride Catalysts for Carbon Dioxide Hydrogenation

et al. 2020

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Catalysts based on molybdenum carbide or nitride nanoparticles (2-5 nm) supported on titania were prepared by wet impregnation followed by a thermal treatment under alkane (methane or ethane)/hydrogen or nitrogen/hydrogen mixture, respectively. The samples were characterized by elemental analysis, volumetric adsorption of nitrogen, X-ray diffraction, and aberration-corrected transmission electron microscopy. They were evaluated for the hydrogenation of CO 2 in the 2-3 MPa and 200-300 • C ranges using a gas-phase flow fixed bed reactor. CO, methane, methanol, and ethane (in fraction-decreasing order) were formed on carbides, whereas CO, methanol, and methane were formed on nitrides. The carbide and nitride phase stoichiometries were tuned by varying the preparation conditions, leading to C/Mo and N/Mo atomic ratios of 0.2-1.8 and 0.5-0.7, respectively. The carbide activity increased for lower carburizing alkane concentration and temperature, i.e., lower C/Mo ratio. Enhanced carbide performances were obtained with pure anatase titania support as compared to P25 (anatase/rutile) titania or zirconia, with a methanol selectivity up to 11% at 250 • C. The nitride catalysts appeared less active but reached a methanol selectivity of 16% at 250 • C.

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“…The catalytic behaviour of β- and γ-Mo 2 N in the partial hydrogenation of acetylene was evaluated by Lizana et al [46] that studied the influence of synthesis parameters on textural properties of the nitrides and its effect on the catalytic performance. The results showed that selectivity of both β- and γ-Mo 2 N was higher than over Pd-based catalysts.…”

Section: Transition Metal Nitrides As Catalystmentioning

confidence: 99%

Recent Progress on Transition Metal Nitrides Nanoparticles as Heterogeneous Catalysts

Dongil

2019

Nanomaterials

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This short review aims at providing an overview of the most recent literature regarding transition metal nitrides (TMN) applied in heterogeneous catalysis. These materials have received renewed attention in the last decade due to its potential to substitute noble metals mainly in biomass and energy transformations, the decomposition of ammonia being one of the most studied reactions. The reactions considered in this review are limited to thermal catalysis. However the potential of these materials spreads to other key applications as photo- and electrocatalysis in hydrogen and oxygen evolution reactions. Mono, binary and exceptionally ternary metal nitrides have been synthetized and evaluated as catalysts and, in some cases, promoters are added to the structure in an attempt to improve their catalytic performance. The objective of the latest research is finding new synthesis methods that allow to obtain smaller metal nanoparticles and increase the surface area to improve their activity, selectivity and stability under reaction conditions. After a brief introduction and description of the most employed synthetic methods, the review has been divided in the application of transition metal nitrides in the following reactions: hydrotreatment, oxidation and ammonia synthesis and decomposition.

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Molybdenum nitrides: a study of synthesis variables and catalytic performance in acetylene hydrogenation

Cited by 24 publications

References 59 publications

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

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

Supported Molybdenum Carbide and Nitride Catalysts for Carbon Dioxide Hydrogenation

Recent Progress on Transition Metal Nitrides Nanoparticles as Heterogeneous Catalysts

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