Activité de V2O5/TiO2 modifié par le phosphore dans la réaction de déshydrogénation oxydante de l'éthane en éthylène

El-Drissi, J.; Kacimi, M. El; Loukah, M.; Ziyad, Mahfoud

doi:10.1051/jcp/1997941984

Cited by 5 publications

(2 citation statements)

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“…This result highlights the role that phosphorus can play as an additive in certain catalytic formulations [14]. ElIdrissi et al [15,16] have reported that the selectivity for ethylene using a catalyst system composed of V/TiO2 modified with phosphorus at a 1.64 of P/V ratio, was close to 50% at a conversion rate of 33%. They attribute the high selectivity to the acid-base properties and the V 4+/ V 5+ ratio and suggest that the presence of phosphorus adjusts the surface acidity, leading to an increase in the amount of isolated V 4+ ions.…”

Section: Introductionmentioning

confidence: 80%

Catalytic Performances of Co/TiO2 Catalysts in the Oxidative Dehydrogenation of Ethane to Ethylene: Effect of CoTiO3 and Co2TiO4 Phases Formation

Mahir¹,

Brik²,

Benzaouak³

et al. 2023

Preprint

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Co/TiO2 catalysts with different cobalt loadings (3.8, 7.5 and 15 wt%) were prepared by impreg-nation method of Co(NO3)2 .6H2O over titania. Samples containing Co(NO3)2 .6H2O and TiO2 in stoichiometric proportions in order to obtain CoTiO3 and Co2 TiO4 phases were also synthesized. The effect of the calcination treatment at two different temperatures, 550 and 1150 °C was investigated. Characterizations by several techniques, such as XRD UV-vis-NIR, DRS, Raman and XPS were carried out. XRD showed the coexistence of three phases: CoTiO3; Co2TiO4 and Co3O4 after calci-nation at 550°C, while the calcination at high temperature (1150°C) leads to single-phase systems (CoTiO3 or Co2TiO4). Diffuse reflection and XPS spectroscopy showed that divalent cobalt occupies octahedral sites in the ilmenite phase and both tetrahedral and octahedral sites in the spinel phase. The catalytic performances of the prepared catalysts, calcined at the two different temperatures, were evaluated in the oxidative dehydrogenation reaction (ODH) of ethane to ethylene. The con-version values were almost comparable for all the samples, calcined at 550 °C, and comparable the ethylene selectivity were recorded, slightly higher only in the case of CoTiO3. The calcination at 1150°C did not modify the overall activity (ethane conversion values around 20%), however, the production of COx becomes more significant. The study examined the influence of the reaction mixture composition, specifically the presence of water, and reveals a slight increase in the yield of ethylene accompanied by a decrease in the overall catalyst activity. This behavior is likely attributed to an increase in the surface concentration of hydroxyl species (OH), resulting in heightened surface acidity.

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Section: Introductionmentioning

confidence: 80%

Catalytic Performances of Co/TiO2 Catalysts in the Oxidative Dehydrogenation of Ethane to Ethylene: Effect of CoTiO3 and Co2TiO4 Phases Formation

Mahir¹,

Brik²,

Benzaouak³

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…This result highlights the role that phosphorus can play as an additive in certain catalytic formulations [14]. ElIdrissi et al [15,16] have reported that the selectivity for ethylene using a catalyst system composed of V/TiO 2 , modified with phosphorus at a 1.64 of P/V ratio, was close to 50% at a conversion rate of 33%. They attribute the high selectivity to the acid-base properties and the V 4+/ V 5+ ratio and suggest that the presence of phosphorus adjusts the surface acidity, leading to an increase in the amount of isolated V 4+ ions.…”

Section: Introductionmentioning

confidence: 81%

Catalytic Performances of Co/TiO2 Catalysts in the Oxidative Dehydrogenation of Ethane to Ethylene: Effect of CoTiO3 and Co2TiO4 Phase Formation

et al. 2023

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Co/TiO2 catalysts with different cobalt loadings (3.8, 7.5 and 15 wt%) were prepared by impregnation method of Co(NO3)2 6H2O over titania. Samples containing Co(NO3)2·6H2O and TiO2 in stoichiometric proportions in order to obtain CoTiO3 and Co2 TiO4 phases were also synthesized. The effect of the calcination treatment at two different temperatures, 550 and 1150 °C, was investigated. Characterizations by several techniques, such as XRD, UV–vis–NIR, DRS, Raman and XPS, were carried out. XRD showed the coexistence of three phases: CoTiO3; Co2TiO4 and Co3O4 after calcination at 550 °C, while calcination at high temperature (1150 °C) led to single-phase systems (CoTiO3 or Co2TiO4). Diffuse reflection and XPS spectroscopy showed that divalent cobalt occupies octahedral sites in the ilmenite phase, and both tetrahedral and octahedral sites in the spinel phase. The catalytic performances of the prepared catalysts were evaluated in the oxidative dehydrogenation reaction (ODH) of ethane to ethylene, as a function of the Co content for Co/TiO2 catalysts and as a function of the calcination temperatures for the CoTiO3 and Co2TiO4 phases. Co(7.5)/TiO2 was the most active, although the conversion of ethane decreased in the first 150 min of the reaction, reaching values comparable to those of Co2TiO4 and CoTiO3; however, Co(7.5)/TiO2 was confirmed as having the best selectivity to ethylene in comparison with the bulk phases, CoTiO3 and Co2TiO4. The influence of the reaction mixture composition, specifically the presence of water, at different percentages, was investigated. There is a decrease in the overall ethane conversion and an increase in the ethylene selectivity when the percentage of water increases. This behavior can likely be attributed to an increase in the surface concentration of hydroxyl species (OH), resulting in heightened surface acidity.

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Titania-Supported Cobalt and Cobalt–Phosphorus Catalysts: Characterization and Performances in Ethane Oxidative Dehydrogenation

Brik

Kacimi

Ziyad

et al. 2001

Journal of Catalysis

229

115

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Activité de V₂O₅/TiO₂ modifié par le phosphore dans la réaction de déshydrogénation oxydante de l'éthane en éthylène

Cited by 5 publications

References 0 publications

Catalytic Performances of Co/TiO2 Catalysts in the Oxidative Dehydrogenation of Ethane to Ethylene: Effect of CoTiO3 and Co2TiO4 Phases Formation

Catalytic Performances of Co/TiO2 Catalysts in the Oxidative Dehydrogenation of Ethane to Ethylene: Effect of CoTiO3 and Co2TiO4 Phases Formation

Catalytic Performances of Co/TiO2 Catalysts in the Oxidative Dehydrogenation of Ethane to Ethylene: Effect of CoTiO3 and Co2TiO4 Phase Formation

Titania-Supported Cobalt and Cobalt–Phosphorus Catalysts: Characterization and Performances in Ethane Oxidative Dehydrogenation

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