Carbide-oxide interactions in bulk and supported tungsten carbide catalysts for alcohol synthesis

Leclercq, Loı̈c; Almazouari, A.; Dufour, M.; Leclercq, G.

doi:10.1007/978-94-009-1565-7_18

Cited by 11 publications

(11 citation statements)

References 26 publications

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“…Figure a contains XPS C 1s spectra for WC and W 2 C thin films for which the CH 4 flow rate was turned off toward the end of the post anneal process. The characteristic carbidic carbon peak for WC is observed at 282.8 eV, while that for W 2 C, which is expected to be lower in intensity and higher in binding energy than WC, is located near 283.7 eV. For both WC and W 2 C surfaces, small C 1s peaks at 284.7 eV are also observed, which originate from adventitious carbon adsorbates from atmosphere.…”

Section: Resultsmentioning

confidence: 94%

“…Of great importance to this study is the TMC surface stoichiometry, which is known to have a profound effect on the catalytic behavior of TMC surfaces. − For example, excess surface carbon has commonly been observed on as-synthesized Pt–WC/W 2 C surfaces, and generally has a prohibitive effect on the catalytic properties of a catalyst. In this study, buildup of excess surface carbon was avoided by shutting off the flow of CH 4 during a post deposition annealing step, which has previously been used to eliminate excess surface carbon in the synthesis of WC powder catalysts .…”

Section: Resultsmentioning

confidence: 99%

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A New Class of Electrocatalysts for Hydrogen Production from Water Electrolysis: Metal Monolayers Supported on Low-Cost Transition Metal Carbides

et al. 2012

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This work explores the opportunity to substantially reduce the cost of hydrogen evolution reaction (HER) catalysts by supporting monolayer (ML) amounts of precious metals on transition metal carbide substrates. The metal component includes platinum (Pt), palladium (Pd), and gold (Au); the low-cost carbide substrate includes tungsten carbides (WC and W(2)C) and molybdenum carbide (Mo(2)C). As a platform for these studies, single-phase carbide thin films with well-characterized surfaces have been synthesized, allowing for a direct comparison of the intrinsic HER activity of bare and Pt-modified carbide surfaces. It is found that WC and W(2)C are both excellent cathode support materials for ML Pt, exhibiting HER activities that are comparable to bulk Pt while displaying stable HER activity during chronopotentiometric HER measurements. The findings of excellent stability and HER activity of the ML Pt-WC and Pt-W(2)C surfaces may be explained by the similar bulk electronic properties of tungsten carbides to Pt, as is supported by density functional theory calculations. These results are further extended to other metal overlayers (Pd and Au) and supports (Mo(2)C), which demonstrate that the metal ML-supported transition metal carbide surfaces exhibit HER activity that is consistent with the well-known volcano relationship between activity and hydrogen binding energy. This work highlights the potential of using carbide materials to reduce the costs of hydrogen production from water electrolysis by serving as stable, low-cost supports for ML amounts of precious metals.

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Section: Resultsmentioning

confidence: 94%

Section: Resultsmentioning

confidence: 99%

A New Class of Electrocatalysts for Hydrogen Production from Water Electrolysis: Metal Monolayers Supported on Low-Cost Transition Metal Carbides

et al. 2012

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“…In particular, the more recent development, of high surface area carbides, has led to an explosion of interest in their use. Consequently, carbides have been shown to be particularly active for hydrotreating, especially hydrodenitrogenation (HDN), − hydrogenation reactions, − the Fischer−Tropsch reaction, ,,− hydroisomerization, ,− and the oxyreforming of methane. − …”

Section: Introductionmentioning

confidence: 99%

Preparation of Molybdenum Carbides Using Butane and Their Catalytic Performance

et al. 2000

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The synthesis of high surface area molybdenum carbides from molybdenum oxide and butane has been studied via temperature-programmed reaction (TPRe), X-ray diffraction (XRD), scanning electron microscopy (SEM), 13 C solid-state NMR, infrared (IR), and Raman spectroscopy (LR). The molybdenum oxygen/carbon system passes through four phase transitions before transforming into the pure Mo 2 C carbide. Carbon exists in two forms within high surface area molybdenum carbide. The initially produced molybdenum carbide has a face-centered-cubic (fcc) structure but is gradually converted into the hexagonal-close-packed (hcp) structure with increasing carburization temperature, and eventually at high temperature coke is deposited. During the early stages, MoO 3 is reduced by H 2 , but at higher temperatures, butane also takes part in the reduction and, besides being consumed in the formation of carbide, is catalytically converted into methane, ethane, propane, and benzene. The high surface area of the molybdenum carbide materials is a consequence of preliminary cracking of oxide crystallites during reduction with hydrogen and later from the deposition of amorphous carbon. Catalytic activity tests indicate that molybdenum carbide material, prepared at 823 K, is a good catalyst for the dehydrogenation of butane. The carbide obtained between 923 and 973 K has excellent performance for pyridine HDN with good selectivity.

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“…Thus, carbides and nitrides have been explored for a wide range of reactions. They have been shown to be particularly active for hydrotreating, especially hydrodenitrogenation (HDN), − hydrogenation reactions, − the Fischer−Tropsch reaction, ,,− hydrocarbon isomerization, ,− and the oxyforming of methane. − …”

Section: Introductionmentioning

confidence: 99%

Study of the Temperature-Programmed Reaction Synthesis of Early Transition Metal Carbide and Nitride Catalyst Materials from Oxide Precursors

et al. 1999

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The synthesis of high surface area carbide and nitride materials from binary and ternary oxides of vanadium, niobium, tantalum, molybdenum, and tungsten, suitable for use as catalysts for a wide range of reactions, has been investigated via the temperatureprogrammed reaction (TPRe) method, in various gas mixtures. TPRe of oxides in CH 4 /H 2 , C 2 H 6 /H 2 , or NH 3 yield materials with surface areas >40 m 2 g -1 . For the reaction with ethane or ammonia the reaction appears to proceed topotactically while that with methane does not; however, the conversion of nitrides to carbides in CH 4 /H 2 does appear to proceed topotactically.

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Carbide-oxide interactions in bulk and supported tungsten carbide catalysts for alcohol synthesis

Cited by 11 publications

References 26 publications

A New Class of Electrocatalysts for Hydrogen Production from Water Electrolysis: Metal Monolayers Supported on Low-Cost Transition Metal Carbides

A New Class of Electrocatalysts for Hydrogen Production from Water Electrolysis: Metal Monolayers Supported on Low-Cost Transition Metal Carbides

Preparation of Molybdenum Carbides Using Butane and Their Catalytic Performance

Study of the Temperature-Programmed Reaction Synthesis of Early Transition Metal Carbide and Nitride Catalyst Materials from Oxide Precursors

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