Enhanced Durability of a Cu/Zeolite Based SCR Catalyst

Cavataio, Giovanni; Jen, Hung-Wen; Warner, James R.; Girard, James W.; Kim, Jeong Y.; Lambert, Christine

doi:10.4271/2008-01-1025

Cited by 59 publications

(32 citation statements)

References 3 publications

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“…4 In addition, the associated problems with zeolite formulations include NO x reduction light-off temperatures, narrow activity window and hydrothermal deterioration, NH 3 adsorption and slippage at low-temperatures limit further commercial applications. [5][6][7] Moreover, automobiles are increasingly equipped with diesel or lean-burn engines, which burn fuel in excess air, oxygen and which are demanded for their environmental and cost-effective advantages with metal oxide catalyst formulations. 8 For the above reasons several research groups are working on the development of potential metal oxide catalysts.…”

Section: Introductionmentioning

confidence: 99%

Influence of SiO₂ on M/TiO₂ (M = Cu, Mn, and Ce) Formulations for Low-Temperature Selective Catalytic Reduction of NO_x with NH₃: Surface Properties and Key Components in Relation to the Activity of NO_x Reduction

Boningari

Pappas

Ettireddy

et al. 2015

Ind. Eng. Chem. Res.

110

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A series of M/TiO 2 and M/TiO 2 -SiO 2 (with M = Mn, Cu and Ce) catalysts were prepared by adopting a wetimpregnation method and investigated for the selective catalytic reduction (SCR) of NO x in the temperature range of 100-500 o C with excess (10 vol.%) oxygen in the feed at industrially relevant conditions. Our XRD results suggest that the growth of crystalline TiO 2 phase is strongly inhibited due to the SiO 2 migration into the TiO 2 lattice. The increase of SiO 2 molar content in TiO 2 -SiO 2 support led to the decrease in anatase phase of titania peak intensity of XRD spectrum and also exhibiting a lower crystallinity of TiO 2 with no phase transition of anatase to rutile. Our XPS depth profile analysis illustrate that the surface atomic ratio of Cu 1+ / Cu 2+ greatly enhanced with increase in TiO 2 content in the TiO 2 -SiO 2 support, and these results are consistent with the H 2 -TPR results where the additional reduction peak evolved at 200 o C for copper loaded titania-rich (Cu/TiO 2 ) catalyst. The high activity of Cu-based TiO 2 formulations has been assigned to the enhancement in the formation of Cu 1+ active sites, existence of surface Cu 2+ , Cu 1+ species and the increment of reduction potentials of surface copper species. The Ce 3+ / Ce 4+ and Ce 3+ /Ce n+ atomic ratio (1.14 and 0.53, respectively) in Ce/TiO 2 catalyst calculated from deconvoluted XPS spectra are much higher than that of Ce/TiO 2 -SiO 2 (1:1) and Ce/TiO 2 -SiO 2 (3:1). The existence of higher Ce 3+ surface species over CeO 2 /TiO 2 illustrates the increment of surface oxygen vacancies and thus facilitates for the adsorption of oxygen species or activates reactants in the SCR reaction. The relative atomic percentage value of Mn 4+ /Mn 3+ characterized by deconvoluted XPS was significantly high (Mn 4+ /Mn 3+ = 1.98) for the Mn/TiO 2 compared to Mn/TiO 2 -SiO 2 catalysts (Mn 4+ /Mn 3+ = 1.23, 1.75). When ceria was supported on pure TiO 2 , the low-temperature reduction peak was broad and less defined, and the reducibility in the low temperature range was much less pronounced. On the other hand, the addition of ceria to titania with strong reciprocal interaction is generally perceived as a shift in the bulk reduction temperature to lower values, to about 500-650 °C. As bigger Ce 4+ ions enter the lattice structure to proxy the Ti 4+ ions with smaller ionic radii (2.48 and 2.15 Å, respectively), the lattice could become highly strained. The NO x conversions and the apparent kinetic constant of the catalyst k ac , over the Cu, Mn, Ce-loaded on different supports TiO 2 and TiO 2 -SiO 2 (3:1 and 1:1) catalysts measured under steady-state conditions results demonstrated higher activity of the Ti-rich materials.

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Section: Introductionmentioning

confidence: 99%

Influence of SiO₂ on M/TiO₂ (M = Cu, Mn, and Ce) Formulations for Low-Temperature Selective Catalytic Reduction of NO_x with NH₃: Surface Properties and Key Components in Relation to the Activity of NO_x Reduction

Boningari

Pappas

Ettireddy

et al. 2015

Ind. Eng. Chem. Res.

110

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“…For after-combustion method (Ibrahim et al 2014;Cavataio 2008), selective catalytic reduction and DeNO x function to control the NO x emissions. The HC and CO gas emissions can be controlled by the diesel oxidation catalyst fixed to exhaust pipes.…”

Section: Emissions Strategymentioning

confidence: 99%

Effect of emulsion fuel on engine emissions–A review

Hasannuddin

Wira

Srithar

et al. 2015

Clean Techn Environ Policy

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Emulsion fuel is an unconventional fuel for diesel engines, which can be used without modifications in the engine. The benefits of an emulsion fuel include lowering the emissions of nitrogen oxides (NO x ) and particulate matter (PM) which are harmful to health and cause diesel engines to suffer. This paper explains in detail the effect of water in the emulsion fuel on the emissions of NO x , PM, carbon monoxide (CO), hydrocarbon (HC), smoke and exhaust temperature. Experimental results from various researchers show a decrease in the NO x and PM emissions simultaneously. However, the results with the increasing water percentage in emulsion fuel are not consistent for HC and CO emissions. The water content in emulsion fuel affects the combustion and reduces the peak temperature in the combustion chamber. On the other hand, microexplosion phenomenon occurs and causes an increase in the volatility of diesel fuel which improves the combustion efficiency.

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“…The race to be compliant with regulatory requirements for diesel engine emissions (or high air-fuel ratio lean-burn gasoline engines) led to extensive work on zeolites and studies found Cu-ZSM-5 3,11,12 and Fe-ZSM-5 [13][14][15] [ Figure 1] to be highly effective NH 3 -SCR catalysts for NO x reduction. The effective temperature range for Cu-ZSM-5 and Fe-ZSM-5 are 250 -450°C and 350 -650°C, 16,17 respectively, enabling a mixture of these two zeolites to reduce NO x in the 250 -650°C range necessary for diesel engines to meet EPA Tier 4 emission standards for the United States. The persistent gradual loss in activity of Cu-and Fe-ZSM-5 led to a search for hydrothermally durable catalyst resulting in the discovery of Cu-SSZ-13 [18][19][20] [ Figure 1] as a NH 3 -SCR catalyst which is now commercially available.…”

Section: Previous Studiesmentioning

confidence: 99%

Nano Catalysts for Diesel Engine Emission Remediation

Narula¹,

Yang²,

Moses-DeBusk³

et al. 2012

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Enhanced Durability of a Cu/Zeolite Based SCR Catalyst

Cited by 59 publications

References 3 publications

Influence of SiO₂ on M/TiO₂ (M = Cu, Mn, and Ce) Formulations for Low-Temperature Selective Catalytic Reduction of NO_x with NH₃: Surface Properties and Key Components in Relation to the Activity of NO_x Reduction

Influence of SiO₂ on M/TiO₂ (M = Cu, Mn, and Ce) Formulations for Low-Temperature Selective Catalytic Reduction of NO_x with NH₃: Surface Properties and Key Components in Relation to the Activity of NO_x Reduction

Effect of emulsion fuel on engine emissions–A review

Nano Catalysts for Diesel Engine Emission Remediation

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Enhanced Durability of a Cu/Zeolite Based SCR Catalyst

Cited by 59 publications

References 3 publications

Influence of SiO2 on M/TiO2 (M = Cu, Mn, and Ce) Formulations for Low-Temperature Selective Catalytic Reduction of NOx with NH3: Surface Properties and Key Components in Relation to the Activity of NOx Reduction

Influence of SiO2 on M/TiO2 (M = Cu, Mn, and Ce) Formulations for Low-Temperature Selective Catalytic Reduction of NOx with NH3: Surface Properties and Key Components in Relation to the Activity of NOx Reduction

Effect of emulsion fuel on engine emissions–A review

Nano Catalysts for Diesel Engine Emission Remediation

Contact Info

Product

Resources

About

Influence of SiO₂ on M/TiO₂ (M = Cu, Mn, and Ce) Formulations for Low-Temperature Selective Catalytic Reduction of NO_x with NH₃: Surface Properties and Key Components in Relation to the Activity of NO_x Reduction

Influence of SiO₂ on M/TiO₂ (M = Cu, Mn, and Ce) Formulations for Low-Temperature Selective Catalytic Reduction of NO_x with NH₃: Surface Properties and Key Components in Relation to the Activity of NO_x Reduction