Catalytic removal of nitric oxide with hydrogen and carbon monoxide in the presence of excess oxygen

Yokota, Kenji; Fukui, M.; Tanaka, Takayuki

doi:10.1016/s0169-4332(97)00305-x

Cited by 112 publications

(72 citation statements)

References 4 publications

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“…The measurements were , depending on the CO content in the gas mixture, which are generally attributed to CO adsorbed in a linear or bridged configuration on the Ru NPs, respectively [24, [35][36][37][38][39][40][41][42][43]. A signal at 2075 cm -1 was assigned previously to CO adsorbed on Ru n+ species [40,44].…”

Section: In-situ Drifts Measurementsmentioning

confidence: 99%

Influence of the catalyst loading on the activity and the CO selectivity of supported Ru catalysts in the selective methanation of CO in CO2 containing feed gases

Eckle

Augustin

Anfang³

et al. 2012

Catalysis Today

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We have investigated the methanation of CO and CO 2 over Ru/zeolite catalysts with different Ru loading in semi-realistic reformate gases by in situ X-ray absorption spectroscopy (XAS), in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and kinetic measurements. Increasing the Ru loading causes an increase of the mean particle size from 0.9 nm (2.2 wt.% Ru) to 1.9 nm (5.6 wt.% Ru). At the same time, also the activity for CO methanation increases, while the selectivity for CO methanation, which is constant at 100% for reformate gases with 0.6% CO, decreases at low CO contents. The latter findings are interpreted in terms of a change in the physical effects governing the selectivity for CO methanation with increasing Ru particle size, from an inherently low activity for CO 2 dissociation and subsequent CO ad methanation on very small Ru nanoparticles to a site blocking mechanism on larger Ru nanoparticles. In the latter mechanism, CO 2 methanation is hindered by a reaction inhibiting adlayer of CO at higher CO ad coverages, i.e., at not too low CO concentrations, but facile in the absence of a CO adlayer, at lower CO concentrations in the reaction gas mixture.

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Section: In-situ Drifts Measurementsmentioning

confidence: 99%

Influence of the catalyst loading on the activity and the CO selectivity of supported Ru catalysts in the selective methanation of CO in CO2 containing feed gases

Eckle

Augustin

Anfang³

et al. 2012

Catalysis Today

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“…Because ammonia synthesis needs hydrogen, it is desirable to use hydrogen directly as NO x reductant, without intermediate processing to ammonia. Therefore, the selective catalytic reduction of NO x by hydrogen (H 2 -SCR), is regarded as good alternative for NH 3 -SCR and is receiving increasing attention.…”

Section: Introductionmentioning

confidence: 99%

“…Supported platinum catalysts are initially found to be active for the H 2 -SCR reaction at low temperatures in 1997 [3]. Subsequently, Pt/SiO 2 [4,5], Pt/TiO 2 -ZrO 2 [6], Pt/La 0.5 Ce 0.5 MnO 3 [7], Pt/ MFI [8,9] and Pt/Mg-Al-O [10] have been reported to be promising catalysts for H 2 -SCR reaction.…”

Section: Introductionmentioning

confidence: 99%

NO selective reduction by hydrogen on potassium titanate supported palladium catalyst

Zhang

Guan

et al. 2008

Catalysis Communications

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a b s t r a c tPotassium titanate (K 2 O-6TiO 2 ) nanowires were successfully prepared by alkali treatment of TiO 2 (79% anatase, 21% rutile) under autogenous pressure in a Teflon-lined autoclave at 200°C. After further modification with 1 wt.% Pd by wet impregnation, the calcined and pre-reduced Pd/K 2 O-6TiO 2 catalyst was applied for selective reduction of NO x by H 2 (H 2 -SCR) under lean conditions, together with Pd/Al 2 O 3 and Pd/TiO 2 as reference. The reference catalysts exhibited maximum NO conversion of about 50-60% at 100-130°C, but with low N 2 selectivity. The N 2 selectivity on Pd/K 2 O-6TiO 2 was considerably high, reaching 80% at maximum, with only 11% conversion of the admixed hydrogen reductant. In situ DRIFT spectroscopy revealed surface-fixed nitrates and Pd-bound NO, but no NH x ad-species. It is concluded, that the beneficial effect of the K 2 O-6TiO 2 support is due mainly to a stabilization of high Pd dispersion with enhanced concentration of Pd 0 -NO intermediates, and due to support alkalinity, that enhances nitrate fixation.

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“…Alternatively, Pt-based catalysts have been found to be the most active for the NO/H 2 /O 2 reaction at low temperatures, e.g., below 200 C (Yokota et al 1997;Frank et al 1998). Yokota et al (1997) have reported NO x removal with H 2 in the presence of O 2 over a Pt-Mo-Na/SiO 2 catalyst.…”

Section: Introductionmentioning

confidence: 99%

Pt/Mg-Ce-O catalyst for NO/H2/O2 lean de-No x reaction

Costa

Efstathiou

2004

Environ Chem Lett

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The NO/H 2 /O 2 reaction was studied under oxidizing conditions in the 100-400 C range over 0.1 wt% Pt supported on various metal oxides such as MgO, CeO 2 , SiO 2 , La 2 O 3 , CaO, Y 2 O 3 and TiO 2 . The Pt/MgO and Pt/ CeO 2 catalysts showed good catalytic behaviours. Here, we find that the Pt/Mg-Ce-O catalyst, prepared from MgO and CeO 2 by the sol-gel method, is a very active and selective catalyst towards N 2 formation in the whole 100-400 C range. This catalyst appears to be the most active, selective and stable one ever reported in the literature for the NO/H 2 /O 2 reaction, even in the presence of 5%v H 2 O or 20 ppmv of SO 2 in the feed stream.

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Catalytic removal of nitric oxide with hydrogen and carbon monoxide in the presence of excess oxygen

Cited by 112 publications

References 4 publications

Influence of the catalyst loading on the activity and the CO selectivity of supported Ru catalysts in the selective methanation of CO in CO2 containing feed gases

Influence of the catalyst loading on the activity and the CO selectivity of supported Ru catalysts in the selective methanation of CO in CO2 containing feed gases

NO selective reduction by hydrogen on potassium titanate supported palladium catalyst

Pt/Mg-Ce-O catalyst for NO/H2/O2 lean de-No x reaction

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