Selective oxidation of ammonia to nitrogen on bi-functional Cu–SSZ-13 and Pt/Al2O3 monolith catalyst

Shrestha, Sachi; Harold, Michael P.; Kamasamudram, Krishna; Kumar, Ashok; Olsson, Louise; Leistner, Kirsten

doi:10.1016/j.cattod.2015.11.035

Cited by 66 publications

(72 citation statements)

References 43 publications

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“…For the second and third test while increasing the volume flow rate, the degree of conversion decreased, as seen in Figures 2 and 3 [21]. Figure 5 (a, b, c, d) shows the results of the tests of the catalysts described in Table 4.…”

Section: Catalytic Methods Of Conversion Of Ammonia To Nitrogenmentioning

confidence: 79%

“…Selective catalytic oxidation (SCO) of ammonia to nitrogen based on reaction (17) [19,20] 16 .4(H 2 O)) [20,21]. The best obtained results are: 60% conversion rate of the ammonia to N 2 with a selectivity of over 90% at 450°C for the composition of the inlet gas: 0.5% ammonia, 2.5% oxygen, 97% of inert gas [20,21].…”

Section: Catalytic Methods Of Conversion Of Ammonia To Nitrogenmentioning

confidence: 99%

“…The best obtained results are: 60% conversion rate of the ammonia to N 2 with a selectivity of over 90% at 450°C for the composition of the inlet gas: 0.5% ammonia, 2.5% oxygen, 97% of inert gas [20,21]. The publication indicates that the catalyst is resistant to water vapour, however, it doesn't show the information about the sensitivity to SO 2 .The SCO process using these catalysts can be carried out in the temperature range of 300-450°C.…”

Section: Catalytic Methods Of Conversion Of Ammonia To Nitrogenmentioning

confidence: 99%

“…The second is based on •NH 2 radical formation, with the intermediate stage comprising hydrazine formation (20)(21)(22)(23) [19,20]: …”

Section: Catalytic Methods Of Conversion Of Ammonia To Nitrogenmentioning

confidence: 99%

“…1. Illustration of the mechanism of selective oxidation of ammonia to nitrogen over a Cu/TiO 2 [19,20] On the other hand, another catalyst system is described by the authors of publication [21]. The study involved Cu-SSZ-13 (a new, more robust and active small-pore Cu-exchanged chabazite (CHA; SSZ-13 and SAPO-34) zeolites have been recently commercialized, in this paperwe explore the effect of using Cu-SSZ-13 as the SCR component of the ASC)andPt/Al 2 O 3 in several variants.…”

Section: Catalytic Methods Of Conversion Of Ammonia To Nitrogenmentioning

confidence: 99%

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Chemical and thermal methods for removing ammonia from fly ashes

Mazur¹,

Janda²,

Żukowski

2017

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The presence of ammonia in ashes (i.e. ammonia slip) is a direct consequence of the methods used for denitrification -selective catalytic and non-catalytic reduction (SCR, SNCR). The excess unreacted ammonia used in both of these methods passes as a constituent to ash, impairing its properties, and thus affects the quality of the commercial product. The summary of the available methods for removing NH 3 from fly ashes is presented. Both chemical and thermal methods of removing NH 3 are described. The results of the chemical methods depend on the kind of additional reagents used and composition of fly ashes. Thermal methods seem to be simpler and easier to use, but they are used mainly on the smaller scale.

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Section: Catalytic Methods Of Conversion Of Ammonia To Nitrogenmentioning

confidence: 79%

Section: Catalytic Methods Of Conversion Of Ammonia To Nitrogenmentioning

confidence: 99%

Section: Catalytic Methods Of Conversion Of Ammonia To Nitrogenmentioning

confidence: 99%

“…The second is based on •NH 2 radical formation, with the intermediate stage comprising hydrazine formation (20)(21)(22)(23) [19,20]: …”

Section: Catalytic Methods Of Conversion Of Ammonia To Nitrogenmentioning

confidence: 99%

Section: Catalytic Methods Of Conversion Of Ammonia To Nitrogenmentioning

confidence: 99%

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Chemical and thermal methods for removing ammonia from fly ashes

Mazur¹,

Janda²,

Żukowski

2017

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Coaxial 3D Printing of Zeolite‐Based Core–Shell Monolithic Cu‐SSZ‐13@SiO₂ Catalysts for Diesel Exhaust Treatment

et al. 2023

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Core–shell catalysts with functional shells can increase the activity and stability of the catalysts in selective catalytic reduction of NOx with ammoniax. However, the conventional approaches based on multistep fabrication for core–shell structures encounter persistent restrictions regarding strict synthesis conditions and limited design flexibility. Herein, a facile coaxial 3D printing strategy is for the first time developed to construct zeolite‐based core–shell monolithic catalysts with interconnected honeycomb structures, in which the hydrophilic noncompact silica serves as shell and Cu‐SSZ‐13 zeolite acts as core. Compared to a Cu‐SSZ‐13 monolith which suffers from the interfacial diffusion, the SiO2 shell layer can increase the accessibility of active sites over Cu‐SSZ‐13@SiO2, resulting in a 10–20% higher NO conversion at200−550 °C under 300 000 cm3 g−1 h−1. Meanwhile, a thicker SiO2 shell enhances the hydrothermal stability of the aged catalyst by inhibiting the dealumination and the formation of CuOx. Other representative monolithic catalysts with different topological zeolites as shell and diverse metal oxides as the core can be also realized by this coaxial 3D printing. This strategy allows multiple porous materials to be directly integrated, which allows for flexible design and fabrication of various core–shell monolithic catalysts with customized functionalities.

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Insight into the Nature of Active Species of Pt/Al₂O₃ Catalysts for low Temperature NH₃ Oxidation

et al. 2019

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Two series of Pt/γ-Al 2 O 3 catalysts for low temperature NH 3 oxidation were prepared using Pt(NO 3 ) 4 and H 2 PtCl 6 precursors. Using both precursors results in the formation of small Pt particles (d < 1.5 nm), however, Cl-containing Pt precursors give a higher fraction of highly dispersed Pt species. Such species show high stability against thermal or H 2 treatment probably due to the presence of a substantial amount of chlorine on the surface. Treatment of the samples prepared from Pt(NO 3 ) 4 with H 2 leads to the formation of metallic Pt nanoparticles accompanied by the improvement of catalytic activity in NH 3 oxidation at T < 200°C. The main products of ammonia oxidation at temperatures below 250°C were molecular nitrogen and nitrous oxide with the N 2 selectivity reaching 80 %. Operando XANES/ EXAFS revealed that even after H 2 pretreatment at least 40 % of Pt surface remains in oxidized state under reaction conditions resulting in the appearance of N 2 O as a by-product.

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Selective oxidation of ammonia to nitrogen on bi-functional Cu–SSZ-13 and Pt/Al2O3 monolith catalyst

Cited by 66 publications

References 43 publications

Chemical and thermal methods for removing ammonia from fly ashes

Chemical and thermal methods for removing ammonia from fly ashes

Coaxial 3D Printing of Zeolite‐Based Core–Shell Monolithic Cu‐SSZ‐13@SiO₂ Catalysts for Diesel Exhaust Treatment

Insight into the Nature of Active Species of Pt/Al₂O₃ Catalysts for low Temperature NH₃ Oxidation

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Selective oxidation of ammonia to nitrogen on bi-functional Cu–SSZ-13 and Pt/Al2O3 monolith catalyst

Cited by 66 publications

References 43 publications

Chemical and thermal methods for removing ammonia from fly ashes

Chemical and thermal methods for removing ammonia from fly ashes

Coaxial 3D Printing of Zeolite‐Based Core–Shell Monolithic Cu‐SSZ‐13@SiO2 Catalysts for Diesel Exhaust Treatment

Insight into the Nature of Active Species of Pt/Al2O3 Catalysts for low Temperature NH3 Oxidation

Contact Info

Product

Resources

About

Coaxial 3D Printing of Zeolite‐Based Core–Shell Monolithic Cu‐SSZ‐13@SiO₂ Catalysts for Diesel Exhaust Treatment

Insight into the Nature of Active Species of Pt/Al₂O₃ Catalysts for low Temperature NH₃ Oxidation