Hydrogen Lean-DeNO<sub>x</sub>as an Alternative to the Ammonia and Hydrocarbon Selective Catalytic Reduction (SCR)

Savva, Petros G.; Costa, Costas N.

doi:10.1080/01614940.2011.557964

Cited by 77 publications

(43 citation statements)

References 119 publications

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“…3,4,7,[13][14][15][16][17][18][19] Among the catalysts proposed for HC-SCR technology, zeolitic oxide catalysts are effective for NO x reduction, while their water tolerance has been little improved. 5 Noble metal catalysts such as Pt/Al 2 O 3 exhibit high deNO x activity in the low temperature range of 200-300 1C while exhibiting a narrow operation temperature window.…”

Section: Introductionmentioning

confidence: 99%

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects

2014

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Selective catalytic reduction of NO x using NH 3 or hydrocarbons (NH 3 -SCR or HC-SCR) in oxygen-rich exhaust from diesel engines remains a major challenge in environmental catalysis. The development of highly efficient, stable and environmentally-benign catalysts for SCR processes is very important for practical use. In this feature article, the structure-activity relationship of vanadium-free catalysts in the NH 3 -SCR reaction is discussed in detail, including Fe-, Ce-based oxide catalysts and Fe-, Cu-based zeolite catalysts, which is beneficial for catalyst redesign and activity improvement. Based on our research, a comprehensive mechanism contributing to the performance of Ag/Al 2 O 3 in HC-SCR is provided, giving a clue to the design of a catalytic system with high efficiency.

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Section: Introductionmentioning

confidence: 99%

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects

2014

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“…Hydrogen has also been considered as the only reductant in H 2 -SCR of NO x , however currently available catalysts allow effective removal of NO x only when using 4 H 2 :NO x > 10 and such amount of hydrogen cannot be produced on board at an affordable price [19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Study of the “Fast SCR”-like mechanism of H2-assisted SCR of NOx with ammonia over Ag/Al2O3

Doronkin¹,

Fogel²,

Tamm³

et al. 2012

Applied Catalysis B: Environmental

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Abstract. It is shown that Ag/Al 2 O 3 is a unique catalytic system for H 2 -assisted selective catalytic reduction of NO x by NH 3 (NH 3 -SCR) with both Ag and alumina being necessary components of the catalyst. The ability of Ag/Al 2 O 3 and pure Al 2 O 3 to catalyse SCR of mixtures of NO and NO 2 by ammonia is demonstrated, the surface species occurring discussed, and a "Fast SCR"-like mechanism of the process is proposed. The possibility of catalyst surface blocking by adsorbed NO x and the *Revised Manuscript Click here to view linked References 2 influence of hydrogen on desorption of NO x were evaluated by FTIR and DFT calculations.

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“…Also present in the exhaust gas is CO which may also participate in the SCR of NO, or, CO-SCR. Thus, the effects (or role) of CO in H 2 -SCR have been of interest, and it has been shown that the presence of CO has a significant influence on H 2 -SCR [23,[31][32][33][34][35]. The presence of CO has a significant promoting influence for some catalysts (e.g., Pd and Ir) while negative effects for others (such as Pt).…”

Section: Introductionmentioning

confidence: 97%

“…Recently, SCR of NO x by H 2 (H 2 -SCR) has attracted attention for NO x removal [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. In H 2 -SCR, hydrogen is used as the reducing agent, by which NO x can be reduced effectively at lower temperatures (T \ 300°C) as compared with ammonia-SCR which operates at near 350°C.…”

Section: Introductionmentioning

confidence: 99%

SCR of Nitric Oxide by Hydrogen over Pd and Ir Based Catalysts with Different Supports

et al. 2015

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Selective catalytic reduction of NO x with hydrogen (H 2 -SCR) in excess oxygen over Pd and Ir based catalysts with various silica supports was studied. The Pd/ V 2 O 5 /TiO 2 /SBA-15 and Ir/SBA-15 catalysts showed the highest activities. The effects of noble metal, various silica supports, CO and SO 2 on H 2 -SCR over these catalysts were also studied and compared, and possible underlying mechanisms discussed. A comparison of 1 % Ir-doped on silicas with a wide range of pore sizes showed that the peak temperature (where the NO conversion maximum was located) was directly related to the pore size: larger pores of the support resulted in higher peak temperatures. This result indicates that pore diffusion limitation played a role in determining the peak temperature. In addition, a nonnoble metal catalyst, Nb 2 O 5 /SiO 2 , was found to have considerable activity.Graphical Abstract Larger pores of the support resulted in higher peak temperatures, which indicated that pore diffusion limitation played a direct role.

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Hydrogen Lean-DeNO_xas an Alternative to the Ammonia and Hydrocarbon Selective Catalytic Reduction (SCR)

Cited by 77 publications

References 119 publications

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects

Study of the “Fast SCR”-like mechanism of H2-assisted SCR of NOx with ammonia over Ag/Al2O3

SCR of Nitric Oxide by Hydrogen over Pd and Ir Based Catalysts with Different Supports

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Hydrogen Lean-DeNOxas an Alternative to the Ammonia and Hydrocarbon Selective Catalytic Reduction (SCR)

Cited by 77 publications

References 119 publications

Environmentally-benign catalysts for the selective catalytic reduction of NOxfrom diesel engines: structure–activity relationship and reaction mechanism aspects

Environmentally-benign catalysts for the selective catalytic reduction of NOxfrom diesel engines: structure–activity relationship and reaction mechanism aspects

Study of the “Fast SCR”-like mechanism of H2-assisted SCR of NOx with ammonia over Ag/Al2O3

SCR of Nitric Oxide by Hydrogen over Pd and Ir Based Catalysts with Different Supports

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Hydrogen Lean-DeNO_xas an Alternative to the Ammonia and Hydrocarbon Selective Catalytic Reduction (SCR)

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects

Environmentally-benign catalysts for the selective catalytic reduction of NO_xfrom diesel engines: structure–activity relationship and reaction mechanism aspects