FTIR Studies on the Acidity of Sulfated Zirconia Prepared by Thermolysis of Zirconium Sulfate

Platero, E. Escalona; Mentruit, M. Peñarroya; Areán, C. Otero; Zecchina, A.

doi:10.1006/jcat.1996.0284

Cited by 109 publications

(40 citation statements)

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“…Figure a shows that (bidentate) sulfate bands between 1400–1000 cm −1 , absent in fresh Ru/ZrO 2 , are clearly evident in the spent catalysts. The broad bands located at around 1400–1340 and 1200–1000 cm −1 are respectively assigned to S=O and S−O stretching vibration modes of the sulfate present on the surface of ZrO 2 . In comparison with fresh Ru/ZrO 2 , two new (weak) bands appeared at approximately 1450 and 1530 cm −1 in the spent catalysts, ascribed to the vibration of C−H groups, indicating some deposition of organic species as well .…”

Section: Figurementioning

confidence: 99%

“…The presence of surface sulfate was furthermore confirmed by the progressive increase in the signal at around 775 K, owing to the oxidation of surface‐bound NH 3 to N 2 by sulfate groups at high temperatures under O 2 ‐free conditions . These findings are clearly in line with the FTIR spectroscopy results and a number of studies on sulfation of ZrO 2 …”

Section: Figurementioning

confidence: 99%

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Influence of Sulfuric Acid on the Performance of Ruthenium‐based Catalysts in the Liquid‐Phase Hydrogenation of Levulinic Acid to γ‐Valerolactone

et al. 2017

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The presence of biogenic or process‐derived impurities poses a major problem on the efficient catalytic hydrogenation of biomass‐derived levulinic acid to γ‐valerolactone; hence, studies on their influence on catalyst stability are now required. Herein, the influence of sulfuric acid as feed impurity on the performance of Ru‐based heterogeneous catalysts, including Ru/ZrO2 and mono‐ and bimetallic Ru‐on‐carbon catalysts in dioxane as solvent, was investigated. The carbon‐supported Ru catalysts proved to be very sensitive to minor amounts of sulfuric acid. In stark contrast, Ru/ZrO2 showed a remarkable stability in the presence of the same impurity, which is attributed to the sulfate‐ion adsorption capacity of the support. Preferential sulfate adsorption onto the surface of ZrO2 effectively protects the Ru active phase from deactivation by sulfur poisoning. A simple catalyst regeneration strategy was effective in removing adsorbed impurities, allowing efficient catalyst recycling.

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Section: Figurementioning

confidence: 99%

Section: Figurementioning

confidence: 99%

Influence of Sulfuric Acid on the Performance of Ruthenium‐based Catalysts in the Liquid‐Phase Hydrogenation of Levulinic Acid to γ‐Valerolactone

et al. 2017

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“…Figure 3 shows the DRIFT spectra obtained. The pronounced shoulder above 1400 cm À1 characteristic of pyrosulfates [45,46] was observed for Cat_SZ1, whereas only contributions from monosulfates were visible in the spectra of Cat_SZ2. Cat_SZ1 therefore appears to contain a significant quantity of www.chemcatchem.org pyrosulfate, which, according to Hofmann and Sauer, [46] is the most stable species on the surface of tetragonal zirconia.…”

Section: Resultsmentioning

confidence: 95%

An Integrated Catalytic and Transient Study of Sulfated Zirconias: Investigation of the Reaction Mechanism and the Role of Acidic Sites in n‐Butane Isomerization

Breitkopf¹

2009

ChemCatChem

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The transient temporal analysis of products (TAP) pulse method has been applied to investigate the isomerization of n‐butane on sulfated zirconias at very low pressure. By combining these results with findings from XRD, XPS, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), temperature‐programmed desorption (TPD), and catalytic studies at atmospheric pressure, a wide range of pressure conditions can be accessed to study the influence of surface sulfate groups on the isomerization activity and the mechanism of this reaction. The catalytic activity of powder catalysts has been correlated to the surface site density of sulfates, with pyrosulfate structures playing a major role in the initiation of the reaction. The complex interplay between sulfate‐free and sulfate‐covered zirconia surfaces for the adsorption of alkanes has been investigated in detail, with TAP pulse experiments showing a monomolecular reaction pathway at low n‐butane partial pressures. Moreover, TAP pulse experiments have allowed detection of the reaction products of this initiation process, including butene and water, and have shown their influence on the deactivation of sulfated zirconias. Heats of adsorption have been calculated from the TAP pulse experiments.

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“…The last intensity peaks are observed at 3438 cm -1 and 3421 cm -1 , which are attributed to the stretching of the O-H alcohol. 17,19 The C5 specimen shows only three intensity peaks when compared with the other specimens. The peaks are recorded at 943 cm -1 , 1632 cm -1 , and 3355 cm -1 , which are due to the bending of the C-H alkene, bending of the N-H and stretching of the SP 2 C-H respectively.…”

Section: Ftir Studiesmentioning

confidence: 93%

“…The number of intense peaks is reduced, while new peaks such as 1666 cm -1 and 2059 cm -1 are formed, which denote the presence of Zr. 19 The next consecutive specimens U3, U4 and U5 show the spectrograms that corresponds to the presence of Cu that has been doped with PVA and Zr at a rate of 6 %, 8 % and 10 %, respectively. From the spectrograms of U3 and U5 the peaks observed are 627cm -1 , 828 cm -1 and 945 cm -1 , which correspond to the presence of the C-H alkene stretch, 20 while U7 does not show the presence of the C-H alkene bond because U7 is doped with 10 % CuSO 4 .…”

Section: Ftir Studiesmentioning

confidence: 99%

Development and characterization of metal-dopant-based zirconia nanofibres via an electrospinning process for scientific applications

Thomas¹,

Judes²

2018

Mater. Tehnol.

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Nanofibres and their composites are some of the emerging materials used in versatile applications due to their better compatible performance. Zirconia nanofibres are examples of such materials. Though zirconia nanofibres have better performance, their conductivity is inferior and to boost their performance, doping with metals is required. Thus, the present study deals with the development of zirconia nanofibres doped with copper and iron in different concentrations and hybrid combinations using the electrospinning method with polyvinyl alcohol as a precursor. The developed materials are subjected to a thermal treatment to develop the properties. Both the thermally treated and untreated fibres were characterized using thermogravimetric analysis, Fourier-transform infrared spectroscopy, X-Ray diffraction, scanning electron microscopy coupled with energy-dispersive analysis, viscosity and conductivity measurements. It was concluded that doping thermally treated zirconia nanofibres with a hybrid combination of copper and iron was beneficial.

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FTIR Studies on the Acidity of Sulfated Zirconia Prepared by Thermolysis of Zirconium Sulfate

Cited by 109 publications

References 0 publications

Influence of Sulfuric Acid on the Performance of Ruthenium‐based Catalysts in the Liquid‐Phase Hydrogenation of Levulinic Acid to γ‐Valerolactone

Influence of Sulfuric Acid on the Performance of Ruthenium‐based Catalysts in the Liquid‐Phase Hydrogenation of Levulinic Acid to γ‐Valerolactone

An Integrated Catalytic and Transient Study of Sulfated Zirconias: Investigation of the Reaction Mechanism and the Role of Acidic Sites in n‐Butane Isomerization

Development and characterization of metal-dopant-based zirconia nanofibres via an electrospinning process for scientific applications

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