Determination of Reactive Species for Alumina-Supported Molybdenum Carbide Catalysts for Methane Reforming Using Temperature-Programmed Reaction Methods

2000 ◽  
Vol 39 (Part 1, No. 7B) ◽  
pp. 4456-4459 ◽  
Author(s):  
Katsuhiko Oshikawa ◽  
Masatoshi Nagai ◽  
Shinzo Omi
Keyword(s):  
Molybdenum Carbide ◽  
Reactive Species ◽  
Methane Reforming ◽  
Temperature Programmed ◽  
Supported Molybdenum Carbide ◽  
Temperature Programmed Reaction

scholarly journals Decomposition of Formic Acid over Orthorhombic Molybdenum Carbide

2021 ◽  
Author(s):  
Kushagra Agrawal ◽  
Alberto Roldan ◽  
Nanda Kishore ◽  
Andrew J Logsdail
Keyword(s):  
Formic Acid ◽  
Density Functional ◽  
Molybdenum Carbide ◽  
Catalyst Surface ◽  
Energy Landscape ◽  
Functional Theory ◽  
Potential Energy Landscape ◽  
Temperature Programmed ◽  
Temperature Programmed Reaction ◽  
Dehydrogenation Mechanism

The decomposition of formic acid is investigated on the β-Mo<sub>2</sub>C (100) catalyst surface using density functional theory. The dehydration and dehydrogenation mechanism for the decomposition is simulated, and the thermochemistry and kinetics are discussed. The potential energy landscape of the reaction shows a thermodynamically favourable cleavage of H-COOH to form CO; however, the kinetics show that the dehydrogenation mechanism is faster and CO<sub>2</sub> is continuously formed. The effect of HCOOH adsorption on the surface is also analysed, in a temperature-programmed reaction, with the decomposition proceeding at under 350 K and desorption of CO<sub>2</sub> observed.

scholarly journals Decomposition of Formic Acid over Orthorhombic Molybdenum Carbide

2021 ◽  
Author(s):  
Kushagra Agrawal ◽  
Alberto Roldan ◽  
Nanda Kishore ◽  
Andrew J Logsdail
Keyword(s):  
Formic Acid ◽  
Density Functional ◽  
Molybdenum Carbide ◽  
Catalyst Surface ◽  
Energy Landscape ◽  
Functional Theory ◽  
Potential Energy Landscape ◽  
Temperature Programmed ◽  
Temperature Programmed Reaction ◽  
Dehydrogenation Mechanism

The decomposition of formic acid is investigated on the β-Mo<sub>2</sub>C (100) catalyst surface using density functional theory. The dehydration and dehydrogenation mechanism for the decomposition is simulated, and the thermochemistry and kinetics are discussed. The potential energy landscape of the reaction shows a thermodynamically favourable cleavage of H-COOH to form CO; however, the kinetics show that the dehydrogenation mechanism is faster and CO<sub>2</sub> is continuously formed. The effect of HCOOH adsorption on the surface is also analysed, in a temperature-programmed reaction, with the decomposition proceeding at under 350 K and desorption of CO<sub>2</sub> observed.

Supported Molybdenum Carbide Catalysts: Structure-Function Relationships for Hydrodenitrogenation

1996 ◽  
Vol 454 ◽  
Author(s):  
Gregory M. Dolce ◽  
Levi T. Thompson
Keyword(s):  
Active Sites ◽  
Molybdenum Carbide ◽  
Metal Carbides ◽  
Model Compounds ◽  
Early Transition Metal ◽  
Molybdenum Carbides ◽  
Temperature Programmed ◽  
Supported Molybdenum Carbide ◽  
Compositional Properties ◽  
Carbide Particles

ABSTRACTEarly transition metal carbides and nitrides have been shown to be active for the hydrotreatment of model compounds and petroleum crudes. In this paper we describe our investigations of the structural and compositional properties of γ-Al2O3-supported molybdenum carbides and efforts to correlate these properties with their pyridine and quinoline hydrodenitrogenation (HDN) activities. The HDN activities of the materials scaled linearly with the loading and oxygen chemisorptive uptake. Oxygen chemisorption results also suggested that the molybdenum carbide particles were highly dispersed and perhaps raft-like. Using temperature programmed desorption and infrared spectroscopy of carbon monoxide, we were able to identify two types of sites on the carbides; sites “on top” of the particle and sites at the perimeter. We have tentatively concluded that the most active sites for HDN were “on top” of the supported carbide particles.

scholarly journals On Catalytic Behavior of Bulk Mo2C in the Hydrodenitrogenation of Indole over a Wide Range of Conversion Thereof

Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1355
Author(s):  
Marek Lewandowski ◽  
Rafał Janus ◽  
Mariusz Wądrzyk ◽  
Agnieszka Szymańska-Kolasa ◽  
Céline Sayag ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Molybdenum Carbide ◽  
Nitrogen Adsorption ◽  
Operating Conditions ◽  
X Ray Diffraction ◽  
Catalytic Behavior ◽  
Wide Range ◽  
Temperature Programmed ◽  
Temperature Programmed Reaction ◽  
Resultant Material

The catalytic activity of bulk molybdenum carbide (Mo2C) in the hydrodenitrogenation (HDN) of indole was studied. The catalyst was synthesized using a temperature-programmed reaction of the respective oxide precursor (MoO3) with the carburizing gas mixture of 10 vol.\% CH4/H2. The resultant material was characterized using X-ray diffraction, CO chemisorption, and nitrogen adsorption. The catalytic activity was studied in the HDN of indole over a wide range of conversion thereof and in the presence of a low amount of sulfur (50 ppm), which was used to simulate the processing of real petroleum intermediates. The molybdenum carbide has shown high activity under the tested operating conditions. Apparently, the bulk molybdenum carbide turned out to be selective towards the formation of aromatic products such as ethylbenzene, toluene, and benzene. The main products of HDN were ethylbenzene and ethylcyclohexane. After 99% conversion of indole HDN was reached (i.e., lack of N-containing compounds in the products was observed), the hydrogenation of ethylbenzene to ethylcyclohexane took place. Thus, the catalytic behavior of bulk molybdenum carbide for the HDN of indole is completely different compared to previously studied sulfide-based systems.

Carbon-Supported Molybdenum Carbide Catalysts for the Conversion of Vegetable Oils

ChemSusChem ◽  
2012 ◽  
Vol 5 (4) ◽  
pp. 727-733 ◽  
Author(s):  
Junxing Han ◽  
Jinzhao Duan ◽  
Ping Chen ◽  
Hui Lou ◽  
Xiaoming Zheng ◽  
...  
Keyword(s):  
Vegetable Oils ◽  
Molybdenum Carbide ◽  
Supported Molybdenum Carbide

Chemical Analyses of Sol/Gel Surfaces and Thin Films

1984 ◽  
Vol 32 ◽  
Author(s):  
Carlo G. Pantano ◽  
C. A. Houser ◽  
R. K. Brow
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Silica Films ◽  
Alumina Films ◽  
Surface Analysis Techniques ◽  
Relative Water ◽  
Temperature Programmed

ABSTRACTThe application of surface analysis techniques to the characterization of sol/gel surfaces and thin films is described. Secondary-ion mass spectroscopy (SIMS), x-ray photoelectron spectroscopy (XPS) and sputter-induced photon spectroscopy (SIPS) are used to measure the composition of multicomponent silicate films, the relative water content of alumina films, the nitrogen content of ammonia treated silica films, and the depth profiles for films on black chrome. The determination of chemical structure using XPS and SIMS is also discussed. Finally, a brief introduction to temperature-programmed desorption (TPD) and its potential for studying surface chemical reactions, in situ, is presented.

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