Preparation and characterization by electrophoretic migration of TiO2—Al2O3 catalytic supports

ZrO 2 -SBA-15 materials with different ZrO 2 loadings (12.5, 25, 37.5, and 50 wt.%) were prepared by incipient wetness impregnation of SBA-15 silica with zirconium (IV) n-propoxide solution and characterized by N 2 physisorption, IEP, and XRD. It was found that the dispersion of zirconia in ZrO 2 -SBA-15 samples decreased with ZrO 2 loading. Nevertheless, about 70-90% of the available support surface was covered with deposited ZrO 2 species leading to high zirconia surface, significantly higher than areas of the traditional bulk ZrO 2 supports. ZrO 2 -SBA-15 materials were used to prepare Mo catalysts, which were characterized (N 2 physisorption, XRD, TPR, and HRTEM) and tested in 4,6-dimethyldibenzothiophene hydrodesulfurization (HDS). Characteristics of Mo species deposited on ZrO 2 -SBA-15 materials with 25-50 wt.% of ZrO 2 and their intrinsic HDS activities were found to be similar to those of the Mo catalyst supported on pure ZrO 2 . Thus, it is shown for the first time that prepared ZrO 2 -SBA-15 materials combine chemical properties of zirconia, attractive for many catalytic applications, with excellent textural characteristics of SBA-15.

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“…(ASC) using the method published by Gil Lliambas et al (1990). The following equation was used for ASC calculation:…”

mentioning

confidence: 99%

APPLICATION OF NEW ZRO₂-SBA-15 MATERIALS AS CATALYTIC SUPPORTS: STUDY OF INTRINSIC ACTIVITY OF MO CATALYSTS IN DEEP HDS

Gutiérrez¹,

Ayala²,

Puente³

et al. 2009

Chemical Engineering Communications

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“…In the water treatment the chlorine of the surface species is replaced by OH groups, which then serve as new bonding sites. In this way a continuous network of new oxide is formed and the XRD patterns of the new oxide cannot be expected before a suitable number of layers is formed. ,,,, Fink et al , and Voronin et al, who report agglomerate formation after the first cycle, have concluded that the agglomerates are formed during the water treatment. According to Meallier et al Haukka et al., , and our earlier work on ZrCl 4 , on the other hand, agglomeration occurs together with direct chlorination during the chloride reaction itself.…”

Section: Discussionmentioning

confidence: 99%

“…In this technique, reactions of gaseous ZrCl 4 and water follow one another, with each reaction continued until surface saturation is achieved. , Closely related methods involving gas−solid reactions have earlier been used for the same purpose of covering the original oxide and preparing high surface area oxides for both catalysts and catalyst supports. Alternating reactions of metal chlorides or oxychlorides and water have been applied in the growth of TiO 2 , − GeO 2 , − SnO 2 , − CrO x , − and V 2 O 5 − on silica, alumina, and titania, but not yet in the growth of ZrO 2 . A great deal of work has also been done in applying sequential reactions of metal chlorides and water to the growth of high quality oxide thin films of Al 2 O 3 , TiO 2 , ZrO 2 , HfO 2 , and SnO 2 (ref and references therein).…”

Section: Introductionmentioning

confidence: 99%

Sequential Saturating Reactions of ZrCl₄ and H₂O Vapors in the Modification of Silica and γ-Alumina with ZrO₂

et al. 1997

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Zirconia-modified silica and alumina samples were prepared by the atomic layer epitaxy technique using successive saturating reactions of ZrCl4 and H2O vapors. The growth of ZrO2 was followed by X-ray diffraction, diffuse reflectance IR Fourier transform spectroscopy, and 1H magic angle spinning NMR measurements. In addition, coverage of the silica surface was estimated by low-energy ion scattering (LEIS). At the reaction temperature of 300 °C the main reaction of ZrCl4, on both supports, occurred with surface OH groups, leading to amorphous ZrCl x species. In addition, part of the molecules reacted to form ZrO2 agglomerates while simultaneously chlorinating OH groups of the supports. Water treatment removed Cl from the ZrCl x surface species, leaving behind Zr−OH groups, and released the directly chlorinated OH groups. Both the reappearing OH groups of the support and the Zr−OH groups were then again available during the next ZrCl4 treatment for both main reactions of ZrCl4. As the reaction cycles were repeated the concentration of amorphous Zr in the samples increased together with the amount of crystalline ZrO2 and surface coverage. On silica, after five cycles of repeated reactions when an average surface density of 5 Zr/nm2 had been achieved, 25% of the original accessible OH groups were still present on the surface. At that point, LEIS measurements showed 50% coverage. On the surface of both silica and alumina, ZrO x was present in the form of tetragonal agglomerates and an amorphous network phase. Two types of Zr−OH groups were identified.

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“…Further we have evaluated the effect of pH on the chemical equilibrium of the tungsten ionic species in solution and their adsorption mechanism on alumina. Some relevant studies from the literature indicated that pH, metal concentration of the solution and ZPC of the support controls the amount and structure of the tungsten oxide species on the surface [40][41][42][43]. At solution pH higher than 7.…”

Section: Physico-chemical Characterization Of Thementioning

confidence: 99%

Conversion of heavy gasoil into ultra-low sulfur and aromatic diesel over NiWRu/TiO₂–γAl₂O₃catalysts: Role of titanium and ruthenium on improving catalytic activity

Silvy¹,

Lageshetty²

2020

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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This contribution deals with about selective conversion of heavy gas oils into middle distillates fuels that meet ultra-low sulfur and aromatic compound quality standards by using a novel NiWRu/TiO2–γAl2O3 catalyst under typical hydrotreatment conditions. A diesel fuel fraction having sulfur, nitrogen and aromatics compound content of about 50 ppm, 10 ppm and 15 v%, respectively, was obtained when the reactor was operated at T = 370 °C, P = 12.4 MPa, LHSV = 0.5 h−1 and H2/hydrocarbon ratio = 800 Nm3/m3. Titanium and ruthenium additives used in the preparation of the NiWRu/TiO2–γAl2O3 catalyst, remarkably improved the catalytic activities for the hydrogenolysis, hydrogenation and hydrocracking reactions compared to the reference NiW/γAl2O3 catalyst. The coprecipitation of titanium and aluminum hydroxides produced a catalyst support having greater surface area, pore volume and surface acidity. An improvement in mechanical properties of the support extrudates was also observed. Characterization analysis by XPS, AUGER and XRD techniques of the TiO2–γAl2O3 support suggested the formation of an aluminum-titanate mixed phase (AlxTiyOz) having a non-well-defined stoichiometry. The NiW/TiO2–γAl2O3 and NiWRu/TiO2–γAl2O3 exhibited a greater surface dispersion of the supported nickel and tungsten species compared to the NiW/γAl2O3 catalyst. The promoter effect of ruthenium on the NiW bimetallic system caused a strong increase in both hydrogenolysis and hydrogenation reactions. Hydrodenitrogenation and hydrocracking reactions were also favored by the increase in the hydrogenation capacity and in the surface acidity of the catalyst. The highest conversion levels for all investigated reactions were obtained when the NiWRu/TiO2–γAl2O3 catalyst was prepared by co-impregnation of Ni and Ru in a second step. This catalyst showed sulfur tolerance properties when the reaction was conducted in the presence of different H2S partial pressures. The catalytic behavior of the NiWRu/TiO2–γAl2O3 catalyst was explained by the existence of a promoting effect between separated Ni and Ru sulfides species and the NiWS phase (dual mechanism).

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Preparation and characterization by electrophoretic migration of TiO2—Al2O3 catalytic supports

Cited by 25 publications

References 13 publications

APPLICATION OF NEW ZRO₂-SBA-15 MATERIALS AS CATALYTIC SUPPORTS: STUDY OF INTRINSIC ACTIVITY OF MO CATALYSTS IN DEEP HDS

APPLICATION OF NEW ZRO₂-SBA-15 MATERIALS AS CATALYTIC SUPPORTS: STUDY OF INTRINSIC ACTIVITY OF MO CATALYSTS IN DEEP HDS

Sequential Saturating Reactions of ZrCl₄ and H₂O Vapors in the Modification of Silica and γ-Alumina with ZrO₂

Conversion of heavy gasoil into ultra-low sulfur and aromatic diesel over NiWRu/TiO₂–γAl₂O₃catalysts: Role of titanium and ruthenium on improving catalytic activity

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Preparation and characterization by electrophoretic migration of TiO2—Al2O3 catalytic supports

Cited by 25 publications

References 13 publications

APPLICATION OF NEW ZRO2-SBA-15 MATERIALS AS CATALYTIC SUPPORTS: STUDY OF INTRINSIC ACTIVITY OF MO CATALYSTS IN DEEP HDS

APPLICATION OF NEW ZRO2-SBA-15 MATERIALS AS CATALYTIC SUPPORTS: STUDY OF INTRINSIC ACTIVITY OF MO CATALYSTS IN DEEP HDS

Sequential Saturating Reactions of ZrCl4 and H2O Vapors in the Modification of Silica and γ-Alumina with ZrO2

Conversion of heavy gasoil into ultra-low sulfur and aromatic diesel over NiWRu/TiO2–γAl2O3catalysts: Role of titanium and ruthenium on improving catalytic activity

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Product

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About

APPLICATION OF NEW ZRO₂-SBA-15 MATERIALS AS CATALYTIC SUPPORTS: STUDY OF INTRINSIC ACTIVITY OF MO CATALYSTS IN DEEP HDS

APPLICATION OF NEW ZRO₂-SBA-15 MATERIALS AS CATALYTIC SUPPORTS: STUDY OF INTRINSIC ACTIVITY OF MO CATALYSTS IN DEEP HDS

Sequential Saturating Reactions of ZrCl₄ and H₂O Vapors in the Modification of Silica and γ-Alumina with ZrO₂

Conversion of heavy gasoil into ultra-low sulfur and aromatic diesel over NiWRu/TiO₂–γAl₂O₃catalysts: Role of titanium and ruthenium on improving catalytic activity