Low temperature selective oxidation of ammonia to nitrogen on silver-based catalysts

Lü, Gang; Anderson, B.; Grondelle, van J Joop; Santen, van Ra Rutger

doi:10.1016/s0926-3373(02)00129-7

Cited by 162 publications

(137 citation statements)

References 23 publications

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“…This mechanism was mainly supported by the results obtained on Pt or transition metal oxide catalysts [1][2][3][4][5]. Two other insights into the reaction mechanism of NH 3 oxidation have been proposed in recent years [6][7][8][9][10][11][12][13]. One is the SCO by a direct route involving a hydrazinium-type intermediate [7,8].…”

Section: Introductionmentioning

confidence: 75%

“…Three major reaction pathways have been proposed for the SCO of NH 3 to N 2 over different catalysts [1][2][3][4][5][6][7][8][9][10][11][12][13]. Zawadzki [1] proposed an imide (NH) mechanism in which the first step yields NH, and then the NH reacts with atomic oxygen (O) to form nitroxyl (HNO) and further conversion to N 2 or nitrous oxide (N 2 O), or NH could even react with molecular O 2 to produce nitric oxide (NO).…”

Section: Introductionmentioning

confidence: 99%

“…The other is a two-step mechanism called in situ or ''internal" selective catalytic reduction (iSCR), which involves the oxidation of a significant percentage of NH 3 into NO x species, and the NO x species subsequently react with NH 3 to form N 2 [9][10][11]. Many noble metal catalysts, such as Ag (powder), Pt, Pt/Al 2 O 3 , Rh/Al 2 O 3 , Pd/Al 2 O 3 , Pt-ZSM-5, Pd-ZSM-5, and Rh-ZSM-5, have been suggested to follow this iSCR route [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, Gang et al [11,13] reported that alumina-supported Ag (Ag/Al 2 O 3 ) catalysts were extremely active in NH 3 oxidation at low temperatures, and the performance of the Ag/Al 2 O 3 catalyst was even superior to that of noble metal catalysts. We investigated the role of Ag species on Ag/Al 2 O 3 in the activity and selectivity of NH 3 oxidation [17].…”

Section: Introductionmentioning

confidence: 99%

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Mechanism of selective catalytic oxidation of ammonia to nitrogen over Ag/Al2O3

Zhang

2009

Journal of Catalysis

193

127

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Mechanism O 2 uptake In situ DRIFTS a b s t r a c tThe mechanism of selective catalytic oxidation (SCO) of NH 3 over Ag/Al 2 O 3 was studied by NH 3 temperature-programed oxidation, O 2 -pulse adsorption, and in situ DRIFTS of NH 3 adsorption and oxidation. The essence which affects the low temperature activity of Ag/Al 2 O 3 has been elucidated through the mechanism study. Different Ag species on Ag/Al 2 O 3 significantly influence O 2 uptake by catalysts; while different oxygen species affect the activity of NH 3 oxidation at low temperature. The activated -NH could react with the atomic oxygen (O) at low temperatures (<140°C); however, the -NH could also interact with the O 2 at temperatures above 140°C. At low temperatures (<140°C), NH 3 oxidation follows the -NH mechanism. However, at temperatures above 140°C, NH 3 oxidation follows an in situ selective catalytic reduction (iSCR) mechanism (two-step formation of N 2 via the reduction of an in situ-produced NO x species by a NH x species).

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Section: Introductionmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Mechanism of selective catalytic oxidation of ammonia to nitrogen over Ag/Al2O3

Zhang

2009

Journal of Catalysis

193

127

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“…9a, the increase in Ag-sputtering time when going from 10 s to 20 s leads to an increase in the absorption peak around 400 nm. This is due to localized surface plasmon resonance [34][35][36]. Fig.…”

Section: Diffuse Reflectance Spectroscopy and Visual Perception Of Pomentioning

confidence: 95%

Photocatalysis/catalysis by innovative TiN and TiN-Ag surfaces inactivate bacteria under visible light

Rtimi

Baghriche

Sanjinés

et al. 2012

Applied Catalysis B: Environmental

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a b s t r a c tThis study presents the design, preparation, testing and characterization of TiN and TiN-Ag nanoparticulate films leading to photocatalytic and catalytic inactivation of Escherichia coli. When Ti was sputtered in N 2 atmosphere, the TiN films unexpectedly revealed semiconductor properties when irradiated under visible light due to the formation of TiO 2 showing absorption in the visible spectral region. In TiN-Ag films, Ag enhances the photocatalytic activity of TiN leading to faster bacterial inactivation. Evidence for the presence of TiO 2 and TiN in the films is presented by XPS. The TiN layers 50 nm thick sputtered by DC for 3 min led to complete inactivation of E. coli within 120 min. But TiN layers with a thickness >50 nm hinder the surface diffusion of charges reducing bacterial inactivation. The rate of TiN deposition was ∼1.4 × 10 15 atoms TiN/cm 2 s. For the TiN-polyester samples under visible light a 3 log 10 bacterial reduction (99.9%) was observed within 30 min while for TiN-Ag samples the same bacterial reduction was attained within ∼15 min. The absorption of the TiN-Ag samples in Kubelka-Munk (KM) units was directly proportional to the E. coli inactivation kinetics. TiN-Ag plasmon nanostructures are concurrently formed under low intensity visible light and accelerated bacterial inactivation. This study shows that TiN films have the potential to replace Ag-based disinfection materials leaching Ag into the environment.

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