An investigation of alumina-supported catalysts for the selective catalytic oxidation of ammonia in biomass gasification

Darvell, L.I.; Heiskanen, Katja; Jones, James C. Peyton; Ross, A.B.; Simell, Pekka; Williams, A.

doi:10.1016/s0920-5861(03)00166-4

Cited by 94 publications

(85 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…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%

“…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]. This mechanism has been reported mainly on the transition metal oxide catalysts such as CuO/Al 2 O 3 , Fe 2 O 3 /TiO 2 , CrO x /TiO 2 , CoO x /TiO 2 , and CuO/ TiO 2 [7,8].…”

Section: Introductionmentioning

confidence: 98%

“…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%

“…One is the SCO by a direct route involving a hydrazinium-type intermediate [7,8]. This mechanism has been reported mainly on the transition metal oxide catalysts such as CuO/Al 2 O 3 , Fe 2 O 3 /TiO 2 , CrO x /TiO 2 , CoO x /TiO 2 , and CuO/ TiO 2 [7,8]. 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].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

Zhang

2009

Journal of Catalysis

203

127

View full text Add to dashboard Cite

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).

show abstract

Section: Introductionmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 98%

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

203

127

View full text Add to dashboard Cite

show abstract

“…Additionally Ni-based catalysts promote the reduction in the reforming temperature, and tan increase in the hydrogen content of the syngas produced [17][18][19]. The influence of the preparation method over the catalysts properties has been previously reported in the literature [18,20], also different oxide supports such as SiO 2 [18,21] and Al 2 O 3 [15,22] have been tested for their efficiency on tar reduction and catalyst properties.…”

Section: Introductionmentioning

confidence: 99%

Characterization and evaluation of Ni/SiO2 catalysts for hydrogen production and tar reduction from catalytic steam pyrolysis-reforming of refuse derived fuel

Blanco

Onwudili

et al. 2013

Applied Catalysis B: Environmental

View full text Add to dashboard Cite

A series of Ni/SiO 2 catalysts have been prepared and investigated for their suitability for hydrogen production and tar reduction in a two-stage pyrolysis-reforming system, using refuse derived fuel (RDF) as the raw material. Experiments were conducted at a pyrolysis temperature of 600 ºC, and a reforming temperature of 800 ºC. The product gases were analysed by gas chromatography (GC) and the condensed fraction was collected and quantified using gas chromatography-mass spectrometry (GC-MS). The effects of the catalyst preparation method, nickel content and the addition of metal promoters (Ce, Mg, Al), were investigated. Catalysts were characterised using BET surface area analysis, temperature programmed oxidation (TPO), and scanning electron microscopy (SEM). The TPO and SEM analysis of the reacted catalysts showed that amorphous type carbons tended to be deposited over the Ni/SiO 2 catalysts prepared by impregnation, while filamentous type carbons were favoured with the sol-gel prepared catalysts. The influence of catalyst promoters (Ce, Mg, Al) added to the Ni/SiO 2 catalyst prepared by the sol-gel method was found not to be significant, as the H 2 production was not increased and the tar formation was not reduced with the metaladded catalyst. The highest H 2 concentration of 57.9 vol.% and lower tar amount produced of 0.24 mg tar /g RDF ; were obtained using the 20 wt.% Ni/SiO 2 catalyst prepared by sol-gel. On the other hand a low catalytic activity for H 2 production and higher tar produced were found for the impregnated series of catalysts, which might be due to the smaller surface area, pore size and due to the formation of amorphous carbons on the catalyst surface. Alkenes and alcohol functional groups were mainly found in the analysed tar samples, with major concentrations of styrene, phenol, indene, cresols, naphthalene, fluorene, and phenanthrene.

show abstract

Catalytic Advancements in NH₃ Selective Catalytic Oxidation: The Impact of Cu‐Induced Lattice Distortion in TiO₂ Crystal Structure

Liu,

Long,

et al. 2024

Chemistry An Asian Journal

View full text Add to dashboard Cite

A series of xCu ‐TiO2 obtained from the sol‐gel method were tested for NH3 selective catalytic oxidation (NH3‐SCO). Its performance was higher than that of supported Cu/TiO2‐Im and solvent‐free Cu/TiO2‐SF. The catalyst exhibits better water resistance at 300 ℃. XRD, Raman, and H2‐TPR proved that the crystal lattice of TiO2 was deformed by Cu doping, which increased the specific surface area of the catalyst. The dispersion of the Cu component is further enhanced. The enhancement of redox potential was the key to improving catalytic activity. The NH3‐TPD results prove that more acidic sites promote more active NH3 species being adsorbed and dissociated on the catalyst surface. The in‐situ DRIFTs results certify that the NH3 species adsorbed on the Lewis acid sites were easier to consume than those on the Brønsted acid sites. The DFT theoretical calculation demonstrates that the doped Cu promotes the TiO2 conduction band to move closer to the Fermi level and enhances the redox performance of the catalyst. The results suggest that the Cu‐TiO2 catalyst was a potential catalyst under actual working conditions, which would provide a technological reserve for the development and diffusion of ammonia slip for both mobile and fixed sources.

show abstract

An investigation of alumina-supported catalysts for the selective catalytic oxidation of ammonia in biomass gasification

Cited by 94 publications

References 25 publications

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

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

Characterization and evaluation of Ni/SiO2 catalysts for hydrogen production and tar reduction from catalytic steam pyrolysis-reforming of refuse derived fuel

Catalytic Advancements in NH₃ Selective Catalytic Oxidation: The Impact of Cu‐Induced Lattice Distortion in TiO₂ Crystal Structure

Contact Info

Product

Resources

About

An investigation of alumina-supported catalysts for the selective catalytic oxidation of ammonia in biomass gasification

Cited by 94 publications

References 25 publications

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

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

Characterization and evaluation of Ni/SiO2 catalysts for hydrogen production and tar reduction from catalytic steam pyrolysis-reforming of refuse derived fuel

Catalytic Advancements in NH3 Selective Catalytic Oxidation: The Impact of Cu‐Induced Lattice Distortion in TiO2 Crystal Structure

Contact Info

Product

Resources

About

Catalytic Advancements in NH₃ Selective Catalytic Oxidation: The Impact of Cu‐Induced Lattice Distortion in TiO₂ Crystal Structure