MORPHOLOGICAL AND STRUCTURAL FEATURES OF CO/TIO2 CATALYSTS PREPARED BY DIFFERENT METHODS AND THEIR PERFORMANCE IN THE LIQUID PHASE HYDROGENATION OF alpha, beta UNSATURATED ALDEHYDES

Aguirre, María del Carmen; Santori, Gerardo Fabián; Ferretti, Osmar A.; Fierro, J.L.G.; Reyes, Patricio

doi:10.4067/s0717-97072006000100008

Cited by 8 publications

(4 citation statements)

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“…Core level spectra of Ti 2p 3/2 and O 1s were also studied and the binding energies are displayed in Table 2. [24,25]. With regard to the Ag/Ti surface atomic ratio an important enhancement with Ag loading is observed, indicative of an increases in the amount of Ag surface atoms.…”

Section: X-ray Photoelectron Spectroscopymentioning

confidence: 94%

CONVERSION OF METHANOL TO FORMALDEHYDE ON TiO2 SUPPORTED Ag NANOPARTICLES

Maldonado¹,

Fierro

Birke³

et al. 2010

J. Chil. Chem. Soc.

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TiO 2 supported Ag nanoparticles with metal loading ranging from 2.0 to 12.0 wt.% have been prepared by reduction of a silver precursor with formic acid under mild conditions. XPS showed that silver remains in a reduced state and TEM has demonstrated that the procedure was effective to produce silver nanoparticles. Only small changes in the metal particle size from 2.0-3.4 nm occurs when the Ag content increases from 2.0 to 12.0 wt.%. O 2 TPD has revealed the presence of different types of adsorbed oxygen species being the one assigned to the active specie called O b which one displayed the highest proportion in the catalysts with higher metal loading. Catalytic activity in the conversion of methanol to formaldehyde showed that those samples with metal loading higher than 7.0 wt% displays higher yields compared to the unsupported silver catalyst.

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Section: X-ray Photoelectron Spectroscopymentioning

confidence: 94%

CONVERSION OF METHANOL TO FORMALDEHYDE ON TiO2 SUPPORTED Ag NANOPARTICLES

Maldonado¹,

Fierro

Birke³

et al. 2010

J. Chil. Chem. Soc.

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“…Furthermore, with only 0.8% Ca modification, Co/TiO 2 obtained the highest CO conversion rate and site-time yield of C 5+ products. The conversion rate is 1.3–1.5 times higher than cosupported SiO 2 catalyst (Figure 4) [97]. Therefore, the CO conversion reaction rate over Co/TiO 2 catalyst was proportionately amplified by increasing the surface area of Co [93].…”

Section: Tio2: As Support In Heterogeneous Catalysismentioning

confidence: 99%

“…(c) TEM micrograph of Co/TiO 2 (673)-SG catalyst after reduction-oxidation-reduction cycle at 773-623-773 K [97]. …”

Section: Figurementioning

confidence: 99%

Titanium Dioxide as a Catalyst Support in Heterogeneous Catalysis

Bagheri

Julkapli

Hamid

2014

The Scientific World Journal

327

176

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The lack of stability is a challenge for most heterogeneous catalysts. During operations, the agglomeration of particles may block the active sites of the catalyst, which is believed to contribute to its instability. Recently, titanium oxide (TiO 2 ) was introduced as an alternative support material for heterogeneous catalyst due to the effect of its high surface area stabilizing the catalysts in its mesoporous structure. TiO 2 supported metal catalysts have attracted interest due to TiO 2 nanoparticles high activity for various reduction and oxidation reactions at low pressures and temperatures. Furthermore, TiO 2 was found to be a good metal oxide catalyst support due to the strong metal support interaction, chemical stability, and acid-base property. The aforementioned properties make heterogeneous TiO 2 supported catalysts show a high potential in photocatalyst-related applications, electrodes for wet solar cells, synthesis of fine chemicals, and others. This review focuses on TiO 2 as a support material for heterogeneous catalysts and its potential applications.

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“…Due to the surface acidity of LT and HT series are similar; almost no changes in selectivity are expected, in agreement with the obtained results. In a previous study of the hydrogenation of α, β unsaturated aldehydes on Co/TiO 2 catalysts it has also been shown that surface and morphological changes affects significantly both, the activity and the selectivity of the reactions [29] The surface acidity of the HT and LT catalysts increases with the addition of niobia due the presence of Si-O-Nb bonds. It is well known that Lewis acid sites are the most active and stereoselectives to isopulegol [25], therefore it should be expected that in these catalysts the selectivity to isopulegols during the citronellal hydrogenation be very high and it can not be neglected that a cyclization of citronellal takes place leading to isopulegol stereoisomers.…”

Section: Tpr and Tpdmentioning

confidence: 98%

SYNTHESIS, CHARACTERIZATION AND CATALYTIC BEHAVIOR OF THE Ir/Nb(2)0(5)/Si0(2) SYSTEM IN THE CITRONELLAL HYDROGENATION

Rojas

Borda

Reyes

et al. 2008

J. Chil. Chem. Soc.

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The citronellal hydrogenation was studied on Ir/Nb 2 O 5-SiO 2 catalysts. A series of catalysts was synthesized with different niobia contents (Ir/N1 1.10%; Ir/N2 2.54%; Ir/N3 3.25%; Ir/N4 5.30%wt%) using the wet impregnation method. These catalysts were reduced in hydrogen atmosphere at low or high temperatures, 473K (LTR) or 773K respectively. Their structural and surface properties were investigated by XRD, TEM, XPS, DTP, FTIR, H 2 chemisorption at 298 K and surface specific area by using the BET method. The X ray diffraction studies revealed only the peaks due to niobia, mainly in those with higher niobia loading. No diffraction lines due to Ir were observed due to its lower content and/or to its high dispersion. The catalytic tests in the hydrogenation of citronellal were carried out in a batch reactor operated at 6.2 bar of H 2 and 343 K. All catalysts showed higher selectivity to isopulegol and to their products due to the cyclization of the citronellal molecule.

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MORPHOLOGICAL AND STRUCTURAL FEATURES OF CO/TIO2 CATALYSTS PREPARED BY DIFFERENT METHODS AND THEIR PERFORMANCE IN THE LIQUID PHASE HYDROGENATION OF alpha, beta UNSATURATED ALDEHYDES

Cited by 8 publications

References 0 publications

CONVERSION OF METHANOL TO FORMALDEHYDE ON TiO2 SUPPORTED Ag NANOPARTICLES

CONVERSION OF METHANOL TO FORMALDEHYDE ON TiO2 SUPPORTED Ag NANOPARTICLES

Titanium Dioxide as a Catalyst Support in Heterogeneous Catalysis

SYNTHESIS, CHARACTERIZATION AND CATALYTIC BEHAVIOR OF THE Ir/Nb(2)0(5)/Si0(2) SYSTEM IN THE CITRONELLAL HYDROGENATION

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