Supported chromia catalysts for oxidation of organic compounds

Pradier, C. M.; Rodrigues, Fábio M. S.; Marcus, Philippe; Landau, Miron V.; Kaliya, M.L.; Gutman, Arie L.; Herskowitz, M.

doi:10.1016/s0926-3373(00)00142-9

Cited by 94 publications

(40 citation statements)

References 26 publications

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“…5). The overall amount of chromium detected and the Cr 6+ /Cr 3+ ratio at the catalyst surface increases gradually with higher Ce loading from 0 to 10% ( Oxidative Dehydrogenation of Ethane to Ethylene 335 higher temperatures which are 467, 468, 471 and 473°C, respectively, suggesting that the oxygen is more strongly bound in the dispersed chromium on the catalyst [36]. From Fig.…”

Section: Textural Properties Of Catalystsmentioning

confidence: 88%

Oxidative Dehydrogenation of Ethane to Ethylene with Carbon dioxide over Cr–Ce/SBA-15 Catalysts

Shi

Wang

2008

Catal Lett

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Chromium oxide supported on SBA-15 was modified with Ce species by an incipient method. The effect of Ce on the activity of Cr/SBA-15 catalyst in the dehydrogenation of ethane with CO 2 was investigated. The activity is enhanced for Ce modified Cr/SBA-15 catalyst for the dehydrogenation of ethane with CO 2 . The cycle between Cr 6+ and Cr 3+ species can be carried out viaing the dehydrogenation of ethane and oxidation of CO 2 processes.

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Section: Textural Properties Of Catalystsmentioning

confidence: 88%

Oxidative Dehydrogenation of Ethane to Ethylene with Carbon dioxide over Cr–Ce/SBA-15 Catalysts

Shi

Wang

2008

Catal Lett

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“…The reaction is endothermic and inevitably controlled by the thermodynamic equilibrium, requiring substantial energy consumption. Supported chromium oxides have also been investigated for the oxidative dehydrogenation of lower alkanes [5][6][7][8][9][10][11] or oxidation of other organic compounds with oxygen [12,13]. However, the use of oxygen as an oxidant is frequently accompanied by deep oxidation, resulting in a decrease in product selectivity.…”

Section: Introductionmentioning

confidence: 99%

Behavior of active sites on Cr-MCM-41 catalysts during the dehydrogenation of propane with CO2

Takehira

Ohishi

Shishido

et al. 2004

Journal of Catalysis

201

160

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“…[10] Ordered mesostructures of transition-metal oxides [11,12] are of immense interest in areas such as catalysis, sorption, chemical and biological separation, photonic and electronic devices, and drug delivery, [13] and well-ordered mesoporous oxides of Mn, [14] Ti, [15,16] V, [17] Zr, [18] W, [15] Nb, [15,17] and Ta [15,18] have been reported. However, the preparation of threedimensionally (3D) ordered mesoporous oxides of Cu, Co, Cr, Ni, and Fe is more difficult, although it has been possible to prepare unstable lamellar phases of these materials.…”

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confidence: 99%

Three‐Dimensional Mesoporous Chromium Oxide: A Highly Efficient Material for the Elimination of Volatile Organic Compounds

2004

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Increasingly strict legislation for controlling the atmospheric emission of industrial volatile organic compounds (VOCs), which contribute to photochemical smog, ground-level ozone, and toxic air emissions, [1][2][3][4] has made the catalytic combustion of hydrocarbons a vital topic of research for the development of new processes for limiting air pollution by VOCs.[5] Oxides of transition metals such as Mn, Cr, Cu, and Co are the most commonly used, cost-effective catalysts for complete oxidation of VOCs, [6][7][8][9] and crystalline chromium oxide, which favors the formation of CO 2 , is the most promising candidate for the total oxidation of organics. [10] Ordered mesostructures of transition-metal oxides [11,12] are of immense interest in areas such as catalysis, sorption, chemical and biological separation, photonic and electronic devices, and drug delivery, [13] and well-ordered mesoporous oxides of Mn, [14] Ti, [15,16] V, [17] Zr, [18] W, [15] Nb, [15,17] and Ta [15,18] have been reported. However, the preparation of threedimensionally (3D) ordered mesoporous oxides of Cu, Co, Cr, Ni, and Fe is more difficult, although it has been possible to prepare unstable lamellar phases of these materials. Recently, hexagonally ordered mesoporous nickel oxide [19] and wormhole-like mesoporous iron oxide [20] have been reported. However, nanoporous 3D structure of oxides are more suitable for application as catalysts or adsorbents as they do not suffer from mass-transfer limitations and therefore allow the easier diffusion of reactants.[21] Transitional-metal oxides are more susceptible to hydrolysis, redox reactions, or phase transitions and possess a number of different coordination numbers and oxidation states, which makes it rather difficult to prepare mesoporous structures from them, unlike silica and aluminosilicates, which can easily form stable mesoporous structures. A neutral templating route has been successfully used for the synthesis of metal-oxide mesostructures [11,15] that are less readily accessible by electrostatic-templating pathways. [12,16] Herein we demonstrate for the first time that a 3D mesoporous chromium oxide material, prepared by a neutral templating route, shows an exceptionally high removal/ oxidation ability for VOCs (toluene, acetaldehyde) after calcination. For transition-metal oxides, control of the rates of precursor hydrolysis, condensation of metal species, and precipitation of mesostructured oxides, for example by slow crystallization, is an important prerequisite for the enhanced framework cross-linking [22,23] that leads to a stable mesoporous structure. We therefore used a metal nitrate salt precursor, a mixed nonaqueous, ethylene glycol/propanol medium, and poly(alkylene oxide) block copolymers as template to prepare a very stable 3D mesoporous structure. The mixed nonaqueous medium allows a very slow crystallization (gelation) process, which favors the formation of a stable mesostructure by enhanced framework cross-linking.

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Supported chromia catalysts for oxidation of organic compounds

Cited by 94 publications

References 26 publications

Oxidative Dehydrogenation of Ethane to Ethylene with Carbon dioxide over Cr–Ce/SBA-15 Catalysts

Oxidative Dehydrogenation of Ethane to Ethylene with Carbon dioxide over Cr–Ce/SBA-15 Catalysts

Behavior of active sites on Cr-MCM-41 catalysts during the dehydrogenation of propane with CO2

Three‐Dimensional Mesoporous Chromium Oxide: A Highly Efficient Material for the Elimination of Volatile Organic Compounds

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