Improving the low temperature NOx reduction activity over a Ag-Al2O3 catalyst

Sitshebo, S.; Tsolakis, Athanasios; Theinnoi, Kampanart; Rodríguez–Fernández, José; Leung, Perry

doi:10.1016/j.cej.2010.01.004

Cited by 27 publications

(18 citation statements)

References 16 publications

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“…Therefore, results have either shown the effectiveness of the catalyst to be low at that temperature or that it is necessary to heat the system, suggesting a decrease in economic efficiency. Thus, the removal of NO x and soot at a low temperature is a worthy research topic that remains of interest to enhance the economic efficiency and to facilitate practical application [34][35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

“…SCR, such as with Ag/Al 2 O 3, is appropriate for NO x removal because of the low cost of Ag in comparison with other noble metals, suggesting a high practical application potential [14,37]. The activity of the catalyst sharply decreases at low operating temperatures (<300 • C), owing to the narrow active temperature window (300-350 • C) for NO x removal [39,40].…”

Section: Introductionmentioning

confidence: 99%

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Plasma-Assisted Selective Catalytic Reduction for Low-Temperature Removal of NOx and Soot Simulant

Nguyen

Heo

et al. 2019

Catalysts

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The challenge that needs to be overcome regarding the removal of nitrogen oxides (NOx) and soot from exhaust gases is the low activity of the selective catalytic reduction of NOx at temperatures fluctuating from 150 to 350 °C. The primary goal of this work was to enhance the conversion of NOx and soot simulant by employing a Ag/α-Al2O3 catalyst coupled with dielectric barrier discharge plasma. The results demonstrated that the use of a plasma-catalyst process at low operating temperatures increased the removal of both NOx and naphthalene (soot simulant). Moreover, the soot simulant functioned as a reducing agent for NOx removal, but with low NOx conversion. The high efficiency of NOx removal required the addition of hydrocarbon fuel. In summary, the combined use of the catalyst and plasma (specific input energy, SIE ≥ 60 J/L) solved the poor removal of NOx and soot at low operating temperatures or during temperature fluctuations in the range of 150–350 °C. Specifically, highly efficient naphthalene removal was achieved with low-temperature adsorption on the catalyst followed by the complete decomposition by the plasma-catalyst at 350 °C and SIE of 90 J/L.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Plasma-Assisted Selective Catalytic Reduction for Low-Temperature Removal of NOx and Soot Simulant

Nguyen

Heo

et al. 2019

Catalysts

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“…in In addition to, its importance in the field of automotive catalytic aftertreatment systems is paramount. In a NOx reduction system of a diesel engine, such as hydrocarbon selective catalytic reduction (HC-SCR), a small amount of hydrogen is used as an ideal co-feeder in order to decrease the minimum temperature needed to drive the NOx removal process [1][2][3][4]. In terms of particulate matter (PM) control, hydrogen promotes the formation of NO2 which is more active than oxygen to oxidise the PM at low temperatures in the regeneration step [5].…”

Section: Introductionmentioning

confidence: 99%

Combination of Langmuir-Hinshelwood-Hougen-Watson and microkinetic approaches for simulation of biogas dry reforming over a platinum-rhodium alumina catalyst

Sawatmongkhon

Theinnoi

Wongchang

et al. 2017

International Journal of Hydrogen Energy

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Dry reforming of CH4 on a platinum-rhodium alumina catalyst is selected to numerically investigate biogas reforming process. Langmuir-Hinshelwood-Hougen-Watson (LHHW) rate expressions for dry reforming and reverse water-gas shift reactions are presented. Activation energies are estimated by combining microkinetics with the theory of unity bond indexquadratic exponential potential (UBI-QEP). Pre-exponential factors are initially obtained by using the transition state theory (TST) and optimised, later, by minimising errors between modelling and experimental data. Adsorption of CH4 on the catalyst surface is found to be the rate determining step in the range of relatively low temperature (600-770 °C), while at relatively high temperature (770-950 °C) the thermal cracking of adsorbed CH4 is the rate controlling step. Small effect of reverse water-gas shift reaction results in the ratio of H2 to CO produced less than unity for all operating conditions. The simulation shows that the dry reforming process proceeds with reaction rate far from equilibrium state. The presented mechanism is capable of predicting the dependence of biogas dry reforming activities (e.g., reactant conversions, product formations, H2 to CO ratio, and temperature profile inside the catalyst) on operating conditions (e.g., inlet temperature, heat supplied through the catalyst wall, and composition of biogas at inlet).

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“…Selective catalytic reduction (SCR) with ammonia has been widely used for the abatement of NO x emissions from stationary sources, especially for coal-fired power plants [1][2][3][4][5] . The commercial catalyst system for NH 3 -SCR process is V 2 O 5 /TiO 2 catalyst promoted by MoO 3 or WO 3 [6][7][8] which showed higher activity of NO x reduction and durability to sulfur compounds.…”

Section: Introductionmentioning

confidence: 99%

Promotional effect of microwave hydrothermal treatment on the low-temperature NH3-SCR activity over iron-based catalyst

Xiong

et al. 2016

Chemical Engineering Journal

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Microwave hydrothermal was introduced into the preparation of iron-cerium-titanium mixed oxide catalyst for NH 3-SCR of NO x , And the catalysts after microwave hydrothermal treatment or not are characterized by X-ray diffraction(XRD), Infrared spectrum(IR), Transmission Electron Microscope(TEM), nitrogen adsorption-desorption and temperature programmed desorption(NH 3 /NO-TPD). Microwave hydrothermal treatment enhanced the low-temperature NH 3-SCR activity of iron-cerium-titanium mixed oxide catalyst, and made its NH 3-SCR reactive temperature window shift to the low-temperature region. Microwave hydrothermal treatment accelerated the crystallite rate of the precursors for iron-cerium-titanium mixed oxide catalysts, adjusted the microscopic pore structure of catalyst, and enlarged the pore diameter and the pore volume of catalyst. Microwave hydrothermal treatment increases Fe and Ce dispersion on the surface of catalyst, and the molar ratio of Ce 3+ /Ce 4+ on the surface of mixed oxide catalyst could also be enhanced after microwave hydrothermal treatment, and improved the relative concentration of Ce 3+ , thereby enhanced the oxidation and reduction properties of catalyst. At the same time, microwave hydrothermal treatment enhanced the low-temperature adsorption

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Improving the low temperature NOx reduction activity over a Ag-Al2O3 catalyst

Cited by 27 publications

References 16 publications

Plasma-Assisted Selective Catalytic Reduction for Low-Temperature Removal of NOx and Soot Simulant

Plasma-Assisted Selective Catalytic Reduction for Low-Temperature Removal of NOx and Soot Simulant

Combination of Langmuir-Hinshelwood-Hougen-Watson and microkinetic approaches for simulation of biogas dry reforming over a platinum-rhodium alumina catalyst

Promotional effect of microwave hydrothermal treatment on the low-temperature NH3-SCR activity over iron-based catalyst

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