Effect of vanadia and tungsten loadings on the physical and chemical characteristics of V2O5-WO3/TiO2 catalysts

Djerad, Souad; Tifouti, L.; Crocoll, Marcus; Weisweiler, Werner

doi:10.1016/j.molcata.2003.07.016

Cited by 156 publications

(90 citation statements)

References 19 publications

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“…% V2O5/WT), Kompio et al [7] (0.5, 1.5, 3.0, 5.0 wt. % V2O5/WT) and Djerad et al [3] (3 and 8 wt. % V2O5/WT).…”

Section: Introductionmentioning

confidence: 86%

“…The rate constant is independent of the active component loading, which is particularly important for coated monoliths where small loading deviations are unavoidable. The NOx reduction efficiency (DeNOx) was estimated according to Equation (3), [3,41],…”

Section: Catalytic Measurementsmentioning

confidence: 99%

“…% V2O5 as the active redox species [3][4][5]. Despite the conventional V2O5 notation, vanadium is actually dispersed as VOx species over the high surface area support [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…The V loading has been investigated on various support materials such as Al2O3, ZrO2, SiO2 or TiO2 [3,7,[26][27][28]. Among these, WT has often been used for V-based SCR catalyst preparation.…”

Section: Introductionmentioning

confidence: 99%

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VOx Surface Coverage Optimization of V2O5/WO3-TiO2 SCR Catalysts by Variation of the V Loading and by Aging

et al. 2015

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V2O5/WO3-TiO2 selective catalytic reduction (SCR) catalysts with a V2O5 loading of 1.7, 2.0, 2.3, 2.6, 2.9, 3.2 and 3.5 wt. % were investigated in the fresh state and after hydrothermal aging at 600 °C for 16 h. The catalysts were characterized by means of nitrogen physisorption, X-ray diffraction and X-ray absorption spectroscopy. In the fresh state, the SCR activity increased with increasing V loading. Upon aging, the catalysts with up to 2.3 wt. % V2O5 exhibited higher NOx reduction activity than in the fresh state, while the catalysts with more than 2.6 wt. % V2O5 showed increasing deactivation tendencies. The observed activation and deactivation were correlated with the change of the VOx and WOx surface coverages. Only catalysts with a VOx coverage below 50% in the aged state did not show deactivation tendencies. With respect to tungsten, above one monolayer of WOx, WO3 particles were formed leading to loss of surface acidity, sintering, catalyst deactivation and early NH3 slip. An optimal compromise between activity and hydrothermal aging resistance could be obtained only with V2O5 between 2.0 and 2.6 wt. %.

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“…% V2O5/WT), Kompio et al [7] (0.5, 1.5, 3.0, 5.0 wt. % V2O5/WT) and Djerad et al [3] (3 and 8 wt. % V2O5/WT).…”

Section: Introductionmentioning

confidence: 86%

Section: Catalytic Measurementsmentioning

confidence: 99%

“…% V2O5 as the active redox species [3][4][5]. Despite the conventional V2O5 notation, vanadium is actually dispersed as VOx species over the high surface area support [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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VOx Surface Coverage Optimization of V2O5/WO3-TiO2 SCR Catalysts by Variation of the V Loading and by Aging

et al. 2015

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“…Kobayashi and Hagi reported their work on the V2O5-WO3 catalysts loaded on the Ti-rich TiO2-SiO2-SO4 2-by the coprecipitation method, and clarified the effect of active components and supports on activities in the selective catalytic reduction of NO by NH3 (Kobayashi and Hagi, 2006). Djerad et al, synthesized V2O5-WO3/TiO2 catalysts by the sol-gel method, and found the catalytic behavior of V2O5-WO3/TiO2 catalyst is strongly dependent on V2O5 content (Djerad et al, 2004). Dong et al, investigated the effect of the pH value of vanadium precursor solution on the catalytic performance of V2O5-WO3/TiO2 catalysts through wet impregnation, and indicated that high de-NOx activity of the V2O5-WO3/TiO2 catalysts can be obtained by enhancing the precursor solution acidity in the preparation process (Dong et al, 2014 Zhang et al, fabricated the V2O5-WO3/TiO2 catalyst by a sol-gel method, and investigate the interaction of V, W and Ti species for the improvement of the catalytic activity in the SCR reaction.…”

Section: Introductionmentioning

confidence: 99%

Effects of V2O5 and WO3 loadings on the catalytic performance of V2O5-WO3/TiO2 catalyst for SCR of NO with NH3

2017

Global NEST Journal

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V2O5-WO3/TiO2 catalysts were fabricated by a simple impregnation method. Effects of V2O5 and WO3 loadings on the catalytic performance of V2O5-WO3/TiO2 catalyst for selective catalytic reduction (SCR) of NO with NH3 were investigated. Morphology and structure of the V2O5-WO3/TiO2 catalysts were characterised by XRD, SEM, XPS, and N2 adsorption techniques. The XRD patterns of the V2O5-WO3/TiO2 catalyst are indexed to anatase-TiO2. XPS spectra analysis confirms that V, Ti, W and O species exist on the surface of V2O5-WO3/TiO2 catalyst. V2O5 species are the main active sites in the process of SCR reaction. Increasing V2O5 loading in the V2O5-WO3/TiO2 catalysts can improve their catalytic performance. Exceeding 2 wt%, the catalytic performance of V2O5-WO3/TiO2 catalyst begins to decline because high V2O5 loading on TiO2 speeds up the growth of anatase grains, which leads to the loss of catalytic activity. Appropriate WO3 species can significantly improve the catalytic performance of V2O5-WO3/TiO2 catalysts. However, as the WO3 loadings reaches 6 wt%, NO conversion decreases instead.

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Catalysis and Reaction Kinetics of a Model Reaction

et al. 2010

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The development of new and the improvement of existing reactor concepts is diffi cult without understanding the reaction mechanism and -if a catalyst is used -its operation principles. In the ideal case an accurate kinetic model with detailed structure -activity relations would be available. However, in industrial practice in general only simplifi ed strategies are applied in order to minimize experimental effort and to reduce the complexity of the corresponding mathematical expressions. Often simplifi ed kinetic models of the power law type are used to describe reaction rates and catalytic performance for a limited parameter range. Nevertheless, for the understanding and the correct prediction of the performance of alternative reactor concepts, as the membrane reactors treated in this book, a more detailed understanding of the kinetic relations is essential. In membrane reactors the concentration profi les of the reactants and the contact time profi les in the catalyst bed are infl uenced simultaneously. A reliable kinetic model has to describe also the reaction behavior for conditions which are far from those present in conventional packed -bed reactors.In order to deliver reliable data for the comparison between conventional and membrane reactors on the one hand, and between different membrane reactor concepts on the other, it is important to study the same reaction system and to apply the same catalyst. In this and the following chapters, the focus is set on the catalyzed oxidative dehydrogenation of ethane ( ODHE ). Although this reaction is currently far from a wide industrial application, it has several advantages for the purpose of this conceptual study:• The expected reaction network is limited to a rather low number of main products and byproducts, which facilitates mechanistic as well as kinetic studies.• There are no condensable products under reaction conditions, which is benefi cial for monitoring the reactor performance with high accuracy.

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Effect of vanadia and tungsten loadings on the physical and chemical characteristics of V2O5-WO3/TiO2 catalysts

Cited by 156 publications

References 19 publications

VOx Surface Coverage Optimization of V2O5/WO3-TiO2 SCR Catalysts by Variation of the V Loading and by Aging

VOx Surface Coverage Optimization of V2O5/WO3-TiO2 SCR Catalysts by Variation of the V Loading and by Aging

Effects of V2O5 and WO3 loadings on the catalytic performance of V2O5-WO3/TiO2 catalyst for SCR of NO with NH3

Catalysis and Reaction Kinetics of a Model Reaction

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