The Selective Catalytic Reduction of NO by Hydrocarbons over Pt- and Ir-Based Catalysts

Amiridis, Michael D.; Mihut, Corina; Maciejewski, Marek; Baiker, Alfons

doi:10.1023/b:toca.0000024343.67581.b3

Cited by 45 publications

(25 citation statements)

References 59 publications

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“…Iridium catalysts have been used in toluene hydrogenation [5,[13][14][15], naphthenic ring opening reactions [16], and selective reduction of nitrogen oxide (NO) [17,18]. In this work, the activity of iridium catalysts was tested in toluene hydrogenation reaction.…”

Section: Introductionmentioning

confidence: 99%

Supported iridium catalysts prepared by atomic layer deposition: effect of reduction and calcination on activity in toluene hydrogenation

Silvennoinen¹,

Jylhä²,

Lindblad

et al. 2007

Catal Lett

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Ligand removal from supported iridium catalysts prepared by atomic layer deposition from Ir(acac) 3 was studied by direct reduction in hydrogen flow and by calcination in oxygen flow followed by reduction in hydrogen flow, as well as by thermogravimetric analysis. Thermal decomposition of acac ligand residuals required high temperatures, and in samples containing no iridium the removal of carbonaceous species was not complete. Metallic iridium particles less than 2 nm in size were formed during direct reduction and larger particles upon calcination followed by reduction. The activity of the catalysts in toluene hydrogenation in most cases depended on particle size.

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Section: Introductionmentioning

confidence: 99%

Supported iridium catalysts prepared by atomic layer deposition: effect of reduction and calcination on activity in toluene hydrogenation

Silvennoinen¹,

Jylhä²,

Lindblad

et al. 2007

Catal Lett

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“…Likewise, we also found some clear features in our DRIFTS study which can be attributed to the organic nitro compound. Figure 6 shows the DRIFT spectra of Co/Al 2 Fig. 6-a).…”

Section: In Situ Steady State Drifts Studymentioning

confidence: 98%

“…Selective catalytic reduction of nitrogen oxides (NO x ) with hydrocarbons (HC-SCR) is a promising method to remove NO x from various exhausts [1,2]. Many studies on HC-SCR are related to the metal-containing zeolitic catalysts [3][4][5] and metal oxides [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

The Nature of Active Sites of Co/Al2O3 for the Selective Catalytic Reduction of NO with C2H4

2009

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The effects of Co loading and calcination temperatures on the catalytic activity of Co/Al 2 O 3 for selective catalytic reduction (SCR) of NO with ethylene in excess oxygen were investigated. Co/Al 2 O 3 showed high and low activities when calcined at high (800°C) and low (350°C) temperatures, respectively. The formation and dispersion of cobalt species for catalysts calcined at 350 and 800°C as well as for Al 2 O 3 were studied by XRD, UV-vis and FTIR spectra. Combined with DRIFTS results of ad-species and reaction experiments, it allowed us to correlate the catalytic activity with active sites of Co/Al 2 O 3 , and the catalytic functions of active cobalt species and support were clarified. Co 3 O 4 species contributed to the oxidation of NO to various nitrates and of C 2 H 4 to reactive formate species, even in the absence of O 2 , whereas the side reaction of ethylene combustion occurred simultaneously when excess oxygen was present. Tetrahedral Co 2? ions in CoAl 2 O 4 , which acted as the active sites, were responsible for the reaction between formate and nitrate species to form organic nitro compound.

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“…In a similar manner, it has been reported that the activity of Ir-based catalysts is notably enhanced after high temperature treatment, which results to the establishment of a certain Ir d? /Ir 0 ratio [44].…”

Section: Effect Of Potassium Addition On Catalysts Activitymentioning

confidence: 99%

Effect of Alkali Promoters (K) on Nitrous Oxide Abatement Over Ir/Al2O3 Catalysts

Papista

Pachatouridou

Goula³

et al. 2016

Top Catal

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The promoting impact of potassium (0-1 wt% K) on nitrous oxide (N 2 O) catalytic decomposition over Ir/ Al 2 O 3 is investigated under both oxygen deficient and oxygen excess conditions. All samples were characterized by means of X-ray powder diffraction (XRD), temperatureprogrammed reduction (H 2 -TPR), ammonia desorption (NH 3 -TPD) and Fourier Transform Infrared Spectroscopy of pyridine adsorption (FTIR-Pyridine). The results reveal that the K-free Ir/Al 2 O 3 catalyst consists mainly of the IrO 2 phase, exhibiting also significant Lewis acidity, which is gradually eliminated by the addition of K. Catalytic performance results showed that the deN 2 O performance in the absence of O 2 in the feed mixture is negatively affected upon increasing potassium loading. However, under oxygen excess conditions, a pronounced effect of K is observed. Although the catalytic performance of the undoped catalyst is drastically hindered by the presence of O 2 , the K-promotion notably prohibits the oxygen poisoning. The optimum deN 2 O performance under oxygen excess conditions is obtained with potassium loading of 0.5 wt% K, which offers complete conversion of N 2 O at 580°C, instead of the corresponding 50 % N 2 O conversion achieved with the un-modified sample. On the basis of characterization results, it was concluded that alkali-doping in combination with oxygen excess conditions are required towards the formation of active Ir entities.

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The Selective Catalytic Reduction of NO by Hydrocarbons over Pt- and Ir-Based Catalysts

Cited by 45 publications

References 59 publications

Supported iridium catalysts prepared by atomic layer deposition: effect of reduction and calcination on activity in toluene hydrogenation

Supported iridium catalysts prepared by atomic layer deposition: effect of reduction and calcination on activity in toluene hydrogenation

The Nature of Active Sites of Co/Al2O3 for the Selective Catalytic Reduction of NO with C2H4

Effect of Alkali Promoters (K) on Nitrous Oxide Abatement Over Ir/Al2O3 Catalysts

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