The effect of metal oxide additives (WO3, MoO3, V2O5, Ga2O3) on the oxidation of NO and SO2 over Pt/Al2O3 and Pt/BaO/Al2O3 catalysts

Dawody, Jazaer; Skoglundh, Magnus; Fridell, Erik

doi:10.1016/j.molcata.2003.08.025

Cited by 63 publications

(35 citation statements)

References 39 publications

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“…The very weak conversion of NO on TsV suggests that the conversion of NO on the bimetallic catalysts occurs mainly on the MoO x and WO x phases. This hypothesis is strongly supported by the observations of Dawody et al [81]. It must thus be understood here that under the conditions used for catalytic abatement of chlorobenzene in the presence of NO, a significant part of the latter was also oxidized to NO 2 .…”

Section: Influence Of Cosupporting

confidence: 84%

Revisiting the Behaviour of Vanadia-Based Catalysts in the Abatement of (Chloro)-Aromatic Pollutants: Towards an Integrated Understanding

et al. 2009

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For several years, the authors study VO x /TiO 2 catalytic formulations in the context of the oxidative abatement of aromatics, possibly chlorinated, from polluted air. This paper revisits their main findings and understandings. Although VO x /TiO 2 catalysts, when upgraded with Mo or W oxides, are already used in industrial applications, it is shown that the systematic investigation (i) of the reasons why optimized synthesis and formulations are indeed efficient, (ii) of the nature of the sites responsible for the adsorption of the pollutants and their catalytic transformation, and (iii) of the corresponding mechanisms, is a valuable approach to identify guidelines and strategies for further improving the catalysts. The origin of the beneficial effects brought by WO x and MoO x to VO x /TiO 2 , and by the use of a sulphated titania support, is addressed, as well as the impact on the catalysts behaviour and performances of molecules inevitably present in a combustion exhaust gas, like CO and NO x co-pollutants and water. The behaviours of a chloroaromatic molecule, like chlorobenzene, and an oxygen containing-heterocyclic molecule, like furan and dimethylfuran, are then compared and discussed in the debate of their selection as representative model compounds for the catalytic abatement of dioxins. In this context, it is shown that strategies developed to improve the performances of VO x /TiO 2 formulations to abate Cl-aromatics, could be detrimental for cyclic molecules containing O-heteroatom, as entire dioxins. Finally, an integrated view of the catalytic process is presented by envisaging the case of a complex mixture, closer to the real application of gaseous effluent cleaning.

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Section: Influence Of Cosupporting

confidence: 84%

Revisiting the Behaviour of Vanadia-Based Catalysts in the Abatement of (Chloro)-Aromatic Pollutants: Towards an Integrated Understanding

et al. 2009

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“…The aim of this work is to determine the effect of Mn and Fe addition on the properties of a Pt/Ba/Al 2 O 3 model catalyst. Mn is known to be active in NO oxidation, a crucial step for the storage process [8,9]. Moreover, Mn can also participate to the NO x storage [10,11] and presents an activity in the NO x reduction by NH 3 reaction [12,13].…”

Section: Introductionmentioning

confidence: 99%

Influence of Mn and Fe Addition on the NO x Storage–Reduction Properties and SO2 Poisoning of a Pt/Ba/Al2O3 Model Catalyst

Corbos

Courtois

et al. 2009

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This work deals with the effect of Mn or Fe addition on the NO x storage-reduction properties of a Pt/Ba/Al 2 O 3 model catalyst. NO x storage capacity, SO 2 poisoning and regeneration and NO x removal efficiency under rich/lean cycling conditions are studied. Fe addition to Pt/Ba/Al 2 O 3 leads only to a small increase of NO x storage capacity, and more interestingly, to a better sulfur removal due to the inhibition of bulk barium sulfate formation. Unfortunately, the NO x storage property cannot be fully recovered. Moreover, Fe addition results in a decrease in the NO x removal efficiency. Mn addition also improves the NO x storage capacity, but no significant influence on the sulfur elimination is observed. Mn-doped catalyst does not improve the NO x removal efficiency, but NH 3 selectivity is found to drastically decrease at 400°C, from 20 to 3%. In addition, the NO x conversion can be improved at higher H 2 concentration in the rich pulse, always keeping NH 3 selectivity at low level.

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“…It is obvious that the NO oxidation activity for all catalysts decreases by the presence of SO 2 but this little effect of SO 2 on the anatase supported catalyst is may be due to WO 3 as a promoter (Dawody et al 2004). Moreover, it hinders both surface area loss of anatase and its transformation into rutile (Busca et al 1998).…”

Section: Discussionmentioning

confidence: 94%

Effects of NO, NO2, CO and SO2 on NO oxidation over Pt/TiO2 for hybrid fast SCR process

2010

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The selective catalytic reduction (SCR) rate of NO with N-containing reducing agents can be enhanced considerably by converting part of NO into NO 2 . The enhanced reaction rate is more pronounced even at lower temperatures by using an equimolar mixture of NO and NO 2 (fast SCR reaction). The oxidation characteristics of NO over catalyst Pt/TiO 2 have been determined in a fixed bed reactor (8 mm-ID) with different concentrations of oxygen, nitric oxide and nitrogen dioxide in the presence of 8% water. The conversion of NO to NO 2 increases with increasing oxygen (O 2 ) concentration from 3 to 12%, but it levels off at higher O 2 concentrations. The NO conversion to NO 2 decreases with increasing NO concentration and it also decreases by an addition of NO 2 in the feed stream. Therefore, the oxidation of NO over Pt/TiO 2 catalyst could be auto-inhibited by the reaction product of NO 2 . The effects of CO and SO 2 on NO oxidation characteristics have also been determined. In fact, the presence of SO 2 significantly suppresses oxidation of NO but due to the less stability of sulfate on anatase structure in TiO 2 , it becomes less significant. On the other hand, the presence of CO increases NO oxidation significantly due to the autoinhibition effect by CO. Moreover, the effect of SO 2 /CO on NO oxidation has also been determined and it was observed that NO oxidation decreases with the increase in SO 2 /CO ratio.

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The effect of metal oxide additives (WO3, MoO3, V2O5, Ga2O3) on the oxidation of NO and SO2 over Pt/Al2O3 and Pt/BaO/Al2O3 catalysts

Cited by 63 publications

References 39 publications

Revisiting the Behaviour of Vanadia-Based Catalysts in the Abatement of (Chloro)-Aromatic Pollutants: Towards an Integrated Understanding

Revisiting the Behaviour of Vanadia-Based Catalysts in the Abatement of (Chloro)-Aromatic Pollutants: Towards an Integrated Understanding

Influence of Mn and Fe Addition on the NO x Storage–Reduction Properties and SO2 Poisoning of a Pt/Ba/Al2O3 Model Catalyst

Effects of NO, NO2, CO and SO2 on NO oxidation over Pt/TiO2 for hybrid fast SCR process

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