Low temperature water-gas shift reaction on cerium containing mordenites prepared by different methods

“…31 In the light of this empirical approach, the bands at 1620 and 1370 cm -1 might be attributed to a monodentate formate species since the frequency separation (250 cm -1 ) is higher than that of a free formate ion (220 cm -1 ). 32 3.4.2.…”

Section: Temperature Programmed Reduction (Tpr)mentioning

confidence: 98%

CO/Water and UV−vis Assisted Assembly of Nanostructured Platinum Wires in Mesoporous Silica

Mohamed

Thabet

2008

J. Phys. Chem. C

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This work describes a method to synthesize free-standing nanoplatinum wires (8-25 nm diameter and 30-100 nm length) fabricated by CO (200 Torr)/water (20 Torr) under a high-pressure Hg lamp at 300 K, for 36 h, induced from H 2 PtCl 6 impregnated with FSM-16 (2.7 nm). On the other hand, stabilized platinum nanoparticles (spherical) grown by consecutive reductive carbonylation of a CO (200 Torr) and CO (20 Torr)/water (2 Torr) system at 323 K exhibited mean particle sizes of 2-10 nm. The structure, dispersion behavior, and surface morphology of the materials have been characterized by temperature programmed surface reaction of CO (TPSR), temperature programmed reduction (TPR), N 2 sorpitometry, and transmission electron microscopy techniques. The Pt nanowires showed a higher catalytic activity toward the water-gas shift reaction (WGSR) than that of nanoparticles. It has been shown that the activity does not depend on the structural and morphological characteristics of Pt/FSM-16 such as specific surface area or primary crystallites size but depends on Pt geometry. Investigation of the surface intermediates observed by in situ Fourier transform infrared spectroscopy formed over Pt nanowires and Pt nanoparticles during the WGSR depicted the developing of unidentate formate species on the former and carbonates on the latter. TPSR demonstrated the facile interaction of CO with nanowires (243-373 K) at lower temperatures, presumably dissociatively, than with nanoparticles (243-493 K). The same result was accomplished using TPR, comprehending that complete reduction was attained at 723 K for the former, but it did not reach completion until 873 K for the latter. This indicated that cationic Pt plays a crucial role in catalyzing WGSR at 323 K. Other issues regarding the binding of CO on Pt particles, declining activity with temperatures, and CO cluster bonds either on Pt nanoparticles or nanowires were also discussed.

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“…The existence of a band at 1558 cm −1 is indicative for oxidative break down of LPY species into carbonaceous surface species; at such low temperature (300 K), implying the existence of considerably reactive basic sites. The latter result was confirmed also through the exposed band at 1680 cm −1 ascribed to νC=O of α-pyridone species [36,37].…”

Section: Pyridine Adsorptionmentioning

confidence: 71%

PHOTOCATALYTIC DEGRADATION OF DIRECT BLUE-1 DYE ON ZrO2, SULPHATED ZrO2 AND V2O5-ZrO2/SO4 CATALYSTS

Othman

Mohmed

Thabet

2010

Al-Azhar Bulletin of Science

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Sulfated (5wt.%) ZrO2 and non-sulfated ZrO2 modified by NH4VO3 using incipient wetness impregnation technique to achieve a loading of 5wt.% V2O5 were thoroughly characterized by means of X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy, N2 sorptiometry, particle size analyzer and pyridine-FT-IR that was used to investigate the acidity of the samples. Degradation of direct blue-1 (DB) dye was tested for the effectiveness of the samples. The results revealed that DB degradation was highly improved with V supported on ZrO2-SO4 and showed a conversion comprises of 95% after UV irradiation (emitting at 365 nm) for 60 min exceeding that of SO4 free ZrO2 sample (68%) obtained at the same period of illumination. This was due to the large surface area (183 m 2 g-1), small crystallites size and presence of basic sites namely O2 − and OH − moieties, those take part in the reaction as additional oxidizing agents. The photocatalytic degradation of DB was found to follow first order rate kinetics. More information on the activity, surface texturing, kinetics and TOC removal were well evaluated, compared and discussed for all samples.

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Low temperature water-gas shift reaction on cerium containing mordenites prepared by different methods

Cited by 28 publications

References 39 publications

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CO/Water and UV−vis Assisted Assembly of Nanostructured Platinum Wires in Mesoporous Silica

PHOTOCATALYTIC DEGRADATION OF DIRECT BLUE-1 DYE ON ZrO2, SULPHATED ZrO2 AND V2O5-ZrO2/SO4 CATALYSTS

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