Thermal stability and surface structure of Mo/CeO2 and Ce-doped Mo/Al2O3 catalysts

Nasser, H.; Rédey, Ákos; Yuzhakova, Tatiana; Kovács, József

doi:10.1007/s10973-008-9050-y

Cited by 18 publications

(5 citation statements)

References 20 publications

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“…The bands at 565 and 700 cm −1 were associated with the out-ofplane C-H bending vibrations of aniline rings. [62] The Raman spectrum of the (Ce III -Mo VI )O x /aniline rods was investigated in the range of 200-3500 cm −1 (Figure 4d). Although the presence of aniline in the (Ce III -Mo VI )O x /aniline hybrid has been proved in combination with various identifications (such as TGA, CHN, UV-Vis and Raman), the C=C vibrations of aromatic rings were not seen which is possibly due to the protonation of the aromatic ring.…”

Section: Figurementioning

confidence: 99%

“…[61] The [1] The band at 904 cm −1 can be attributed to ν (Ce-O-Mo) or ν (Ce-O-Ce). [62] The Raman spectrum of the (Ce III -Mo VI )O x /aniline rods was investigated in the range of 200-3500 cm −1 (Figure 4d). The peaks at 656, 814 and 985 cm −1 were attributed to the Mo 3 -O, Mo 2 -O and Mo = O stretching modes of molybdate, respectively.…”

Section: Characterization Of (Ce III -Mo Vi )O X / Aniline Rodsmentioning

confidence: 99%

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Scaled‐up, selective and green synthesis of sulfoxides under mild conditions using (Ce^III‐Mo^VI)O_x/aniline hybrid rods as an efficient catalyst

Feghhi

Malakooti

2019

Applied Organom Chemis

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A novel hybrid material, (Ce III -Mo VI )O x /aniline, with rod-like morphology is synthesized through a wet chemical method using Mo 3 O 10 (C 6 H 5 NH 3 ) 2 .2H 2 O nanowires as precursor. The synthesized materials are characterized by XRD, XPS, SEM, TEM, FTIR, Raman, UV-Vis, TGA, and elemental analysis. Also, their catalytic activities as a hybrid catalyst are tested in the selective oxidation of sulfides using hydrogen peroxide as a green oxidant. The proposed novel hybrid catalyst shows an excellent performance under green conditions at mild temperature. Furthermore, the scalability of the oxidation reaction is shown by making multi-gram quantities at optimized conditions.

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Section: Figurementioning

confidence: 99%

Section: Characterization Of (Ce III -Mo Vi )O X / Aniline Rodsmentioning

confidence: 99%

Scaled‐up, selective and green synthesis of sulfoxides under mild conditions using (Ce^III‐Mo^VI)O_x/aniline hybrid rods as an efficient catalyst

Feghhi

Malakooti

2019

Applied Organom Chemis

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“…the thermogram obtained for CeMo (Table 2 and Figure S1, Supplementary Materials), only one thermal decomposition event was observed above 1000 °C (with a mass loss of 19%), which clearly continues to occur, but which is not quantified due to the limitation of the equipment, which operates at a maximum temperature of 1500 °C. This suggests that the interaction between the molybdenum and cerium ions for the formation of cerium molybdate leads to an increase in thermal stability, and the mass loss above 850 °C is associated with the decomposition of the material into cerium and molybdenum oxide and the subsequent sublimation of MoO3 [47][48][49]. Reports indicate that in this type of material, when subjected to temperatures above 700 °C, defects are formed that favor greater mobility of the molybdenum and cerium ions, consequently leading to changes in the mutual interaction between them, leading to increased thermal stability [48].…”

Section: Without Catalyst↑ Ce100↑mentioning

confidence: 99%

“…This suggests that the interaction between the molybdenum and cerium ions for the formation of cerium molybdate leads to an increase in thermal stability, and the mass loss above 850 °C is associated with the decomposition of the material into cerium and molybdenum oxide and the subsequent sublimation of MoO3 [47][48][49]. Reports indicate that in this type of material, when subjected to temperatures above 700 °C, defects are formed that favor greater mobility of the molybdenum and cerium ions, consequently leading to changes in the mutual interaction between them, leading to increased thermal stability [48].…”

Section: Without Catalyst↑ Ce100↑mentioning

confidence: 99%

Investigation of CeO2, MoO3, and Ce2(MoO4)3, Synthesized by the Pechini Method, as Catalysts for Fructose Conversion

et al. 2022

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Cerium oxide (Ce100), molybdenum oxide (Mo100), and a material containing Ce and Mo (CeMo) were synthesized by the Pechini method, using glycerol as a polyol. These materials were applied for fructose conversion in an aqueous medium. The characterization results show the formation of cerium molybdate (Ce2(MoO4)3) for CeMo. Ce100 presented good thermal stability, and Mo100 sublimation of MoO3 and polymolybdates was verified. CeMo exhibited a mass loss of 19%, associated with the sublimation of MoO3 and polymolybdate species. Additionally, the existence of Bronsted and Lewis acid sites was confirmed, and the addition of Mo to Ce was an efficient strategy to increase the acidity. Regarding the catalytic activity (150 °C and 0.5 to 6 h), Ce100 exhibited low conversions and high selectivity to 5-hydroxymethylfurfural (5-HMF). For Mo100, high conversions, with a significant formation of insoluble materials, were detected. For CeMo, beyond the high activity, a lower formation of insoluble materials was noted. In this case, selectivity toward products from the retro–aldolic route and 5-HMF were obtained. These results indicate that the main factor influencing fructose conversion is an adequate combination of the acid sites. Recycling experiments were carried out, and stability was observed for four cycles, confirming the robustness of this system.

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“…The Mo surface densities of the supported MoO 3 /cAl 2 O 3 catalysts are expressed as the number of Mo atoms per square nanometer of surface area (Mo atoms/nm 2 ) [15]. They were calculated from the actual molybdena content and the corrected surface area of the alumina support and are given in Table 1.…”

Section: Catalyst Characterizationmentioning

confidence: 99%

Catalytic dehydrogenation of cyclohexene over MoO3/γ-Al2O3 catalysts

Kady

Shaban

Naga

2011

Transition Met Chem

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A series of MoO 3 /c-Al 2 O 3 catalysts with different Mo surface densities (Mo atoms/nm 2 ) has been prepared by incipient wetness impregnation method. Structural characteristics of the prepared catalysts were investigated by atomic absorption spectroscopy, X-ray diffraction, Fourier Transform Infrared spectroscopy, N 2 adsorption at -196°C, and temperature-programmed reduction (TPR). The catalytic activities of the prepared catalysts were tested by cyclohexene conversion between 200 and 400°C. XRD results indicated that molybdenum oxide species were dispersed as a monolayer on the support up to 4.04 Mo atoms/nm 2 , and the formation of crystalline MoO 3 was observed above this loading. FTIR and TPR results showed that molybdenum oxide species were present predominantly in tetrahedral form at lower loading, and polymeric octahedral forms were dominant at higher loading. Cyclohexene conversion reaction proceeded mainly through the simple dehydrogenation pathway in the studied temperature range 200-400°C and was found to be highly dependent on MoO 3 dispersion.

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Thermal stability and surface structure of Mo/CeO2 and Ce-doped Mo/Al2O3 catalysts

Cited by 18 publications

References 20 publications

Scaled‐up, selective and green synthesis of sulfoxides under mild conditions using (Ce^III‐Mo^VI)O_x/aniline hybrid rods as an efficient catalyst

Scaled‐up, selective and green synthesis of sulfoxides under mild conditions using (Ce^III‐Mo^VI)O_x/aniline hybrid rods as an efficient catalyst

Investigation of CeO2, MoO3, and Ce2(MoO4)3, Synthesized by the Pechini Method, as Catalysts for Fructose Conversion

Catalytic dehydrogenation of cyclohexene over MoO3/γ-Al2O3 catalysts

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Thermal stability and surface structure of Mo/CeO2 and Ce-doped Mo/Al2O3 catalysts

Cited by 18 publications

References 20 publications

Scaled‐up, selective and green synthesis of sulfoxides under mild conditions using (CeIII‐MoVI)Ox/aniline hybrid rods as an efficient catalyst

Scaled‐up, selective and green synthesis of sulfoxides under mild conditions using (CeIII‐MoVI)Ox/aniline hybrid rods as an efficient catalyst

Investigation of CeO2, MoO3, and Ce2(MoO4)3, Synthesized by the Pechini Method, as Catalysts for Fructose Conversion

Catalytic dehydrogenation of cyclohexene over MoO3/γ-Al2O3 catalysts

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Scaled‐up, selective and green synthesis of sulfoxides under mild conditions using (Ce^III‐Mo^VI)O_x/aniline hybrid rods as an efficient catalyst

Scaled‐up, selective and green synthesis of sulfoxides under mild conditions using (Ce^III‐Mo^VI)O_x/aniline hybrid rods as an efficient catalyst