Temperature-programmed reduction and zeta potential studies of the structure ofMo/O3Al2O3 andMo/O3SiO2 catalysts effect of the impregnation pH and molybdenum loading

López-Cordero, Rafael; Llambías, F.J. Gil; Agudo, Antonio

doi:10.1016/0166-9834(91)90013-x

Cited by 134 publications

(72 citation statements)

References 17 publications

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“…Hydrogen consumption between 500 and 600 C can be associated with the second reduction step of small MoO 3 clusters or with the first reduction step of polymeric Oh Mo species with larger degree of polymerization. Comparing the present TPR pattern with that of bulk MoO 3 (main peak at 600 -630 C, L o opez Cordero et al, 1991), the signal observed at 600 -610 C can be assigned to the reduction of crystalline MoO 3 phase detected by XRD. The last signal became less defined in the TRP pattern of Mo=ZrO 2 (12)-SBA-15 catalyst (curve b, Figure 3) for which only some traces of MoO 3 crystalline phase were detected by XRD characterization.…”

Section: Catalystsmentioning

confidence: 93%

“…Two well-defined reduction peaks at 410 and 690 C were observed in the TPR profile of the Mo catalyst supported on pure ZrO 2 . The first one is assigned to the first step of reduction (from Mo 6þ to Mo 4þ ) of dispersed octahedral (Oh) Mo species and the second to the first step of reduction of tetrahedral (Td) Mo species strongly bound to Cordero et al, 1991;Kostova et al, 2001). In addition, hydrogen consumption in the 500 -600 C temperature range corresponds to the second step of reduction of Oh Mo species (from Mo 4þ to Mo 0 ).…”

Section: Catalystsmentioning

confidence: 99%

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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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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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Section: Catalystsmentioning

confidence: 93%

Section: Catalystsmentioning

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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“…According to Refs. [7,8], the l, m and h peaks correspond to the reduction of polymolybdate or multilayered Mo oxide to MoO 2 , Al 2 (MoO 4 ) 3 and microcrystalline MoO 3 to MoO 2 , and MoO 2 to Mo, respectively. As shown in Fig.…”

Section: Reaction Performance Of Catalysts With Different Mo Contentsmentioning

confidence: 99%

Metathesis of ethylene and butylene-2 to propylene with Mo on Hβ-Al2O3 catalysts

et al. 2004

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“…The low temperature peak around 500 °C was very broad and more intense, associated to the reduction of Mo 6+ to Mo 4+ of polymeric octahedral Mo species and NiMoO4 − -like phase weakly bound to the zeolite surface [31,32]. The reduction peak at about 730 °C was assigned to the reduction of tetrahedrally coordinated Mo species (MoO3 phase) in the zeolite cavities [33,34]. After AHFS treatments, the peak at ca.…”

Section: Influence Of Dealumination and Desilication On The Metal Statementioning

confidence: 99%

Hydroconversion of Waste Cooking Oil into Green Biofuel over Hierarchical USY-Supported NiMo Catalyst: A Comparative Study of Desilication and Dealumination

et al. 2017

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Abstract:The hydroconversion of waste cooking oil into hydrocarbon fuel was investigated over the hierarchical USY zeolite-supported NiMo catalysts which were prepared by dealumination ((NH 4 ) 2 SiF 6 )/desilication (NaOH). The physical and acidity properties of the hierarchical catalysts were characterized by X-ray diffraction (XRD), the Brunauer-Emmett-Teller (BET) infrared spectroscopy of adsorbed pyridine (Py-IR), ammonia temperature-programmed desorption (NH 3 -TPD), and H 2 temperature-programmed reduction (H 2 -TPR). The Brønsted/Lewis (B/L) acid distribution was little affected by dealumination and the acid density decreased significantly. However, the highly-desilicated catalysts decreased the B/L ratio obviously. Therefore, many more Mo species in the NiMoO 4 − and MoO 3 phases were produced in the AHFS-treated catalysts, while more high-valence-state Mo species in the NiMoO 4 − phase were formed in the NaOH-treated catalysts.The AHFS-treated catalysts showed higher catalytic activity and better DCO 2 selectivity and selective cracking for jet fuel. The 42.3% selectivity of jet fuel and 13.5% selectivity of jet-range aromatics was achieved over the 8 wt % (NH 4 ) 2 SiF 6 -treated catalyst with 67% DCO 2 selectivity.

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Temperature-programmed reduction and zeta potential studies of the structure ofMo/O3Al2O3 andMo/O3SiO2 catalysts effect of the impregnation pH and molybdenum loading

Cited by 134 publications

References 17 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

Metathesis of ethylene and butylene-2 to propylene with Mo on Hβ-Al2O3 catalysts

Hydroconversion of Waste Cooking Oil into Green Biofuel over Hierarchical USY-Supported NiMo Catalyst: A Comparative Study of Desilication and Dealumination

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Temperature-programmed reduction and zeta potential studies of the structure ofMo/O3Al2O3 andMo/O3SiO2 catalysts effect of the impregnation pH and molybdenum loading

Cited by 134 publications

References 17 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

Metathesis of ethylene and butylene-2 to propylene with Mo on Hβ-Al2O3 catalysts

Hydroconversion of Waste Cooking Oil into Green Biofuel over Hierarchical USY-Supported NiMo Catalyst: A Comparative Study of Desilication and Dealumination

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Product

Resources

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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