Oxidation of ammonia over a copper oxide-containing solid oxygen carrier with oxygen uncoupling capability

Normann, Fredrik; Cheng, Mao; Li, Zhenshan; Cai, Ningsheng; Leion, Henrik

doi:10.1016/j.combustflame.2015.12.029

Cited by 15 publications

(11 citation statements)

References 18 publications

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“…Thus, it is postulated that aggregated copper species are more active in ammonia oxidation compared to monomeric copper cations. Similar conclusions have been already reported in scientific literature [8,18]. Another very significant difference is related to the high temperature selectivity to dinitrogen, which is significantly lower for Cu/Ti-FER than for Cu/Al-FER ( Figure 7a).…”

Section: Catalytic Studiessupporting

confidence: 90%

“…The various porous structures, microporous in the case of ferrierite and bimodal microporous and mesoporous in the case of ITQ-6, should not only influence the internal diffusion rate of reactants inside pores but also forms of deposited copper species, which, depending on aggregation, may play a different role in the studied process [8]. Aggregated copper oxide species were reported to be catalytically active in direct ammonia oxidation to NO [18], thus the presence of such species may activate catalysts for the low-temperature ammonia oxidation but to the undesired reaction product. On the other side, highly dispersed copper species, mainly monomeric copper cations, are known to be catalytically active in the process of selective catalytic reduction of NO with ammonia to dinitrogen, NH 3 -SCR, [17].…”

Section: Introductionmentioning

confidence: 99%

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Ferrierite and Its Delaminated Forms Modified with Copper as Effective Catalysts for NH3-SCO Process

et al. 2020

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Ferrierites and their delaminated forms (ITQ-6), containing aluminum or titanium in the zeolite framework, were synthetized and modified with copper by an ion-exchange method. The obtained samples were characterized with respect to their chemical composition (ICP-OES), structure (XRD, UV-Vis DRS), textural parameters (N2-sorption), surface acidity (NH3-TPD), form and reducibility of deposited copper species (UV-Vis DRS and H2-TPR). Ferrierites and delaminated ITQ-6 zeolites modified with copper were studied as catalysts for the selective catalytic oxidation of ammonia to dinitrogen (NH3-SCO). It was shown that aggregated copper oxide species, which were preferentially formed on Ti-zeolites, were catalytically active in direct low-temperature ammonia oxidation to NO, while copper introduced into Al-zeolites was present mainly in the form of monomeric copper cations catalytically active in selective reduction of NO by ammonia to dinitrogen. It was postulated that ammonia oxidation in the presence of the studied catalysts proceeds according to the internal-selective catalytic reduction mechanism (i-SCR) and therefore the suitable ratio between aggregated copper oxide species and monomeric copper cations is necessary to obtain active and selective catalysts for the NH3-SCO process. Cu/Al-ITQ-6 presented the best catalytic properties possibly due to the most optimal ratio of these copper species.

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Section: Catalytic Studiessupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Ferrierite and Its Delaminated Forms Modified with Copper as Effective Catalysts for NH3-SCO Process

et al. 2020

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“…In Figure S10 we provide the results for bulk Cu XANES standards collected at the Cu K-edge. The grazing incidence X-ray absorption near edge spectroscopy (GIXANES) results are shown in Figure S11 for Cu 4 , Cu 12 , and C 20 .…”

Section: Resultsmentioning

confidence: 99%

“…Similarly, at subnanometer sizes, trinuclear copper‐oxo clusters have high reactivity toward conversion of methane to methanol . There are also other reactions where the active species is known to be Cu 2 O (e.g., the oxidation of CO) or CuO (e.g., the oxidation of NH 3 into NO or N 2 , soot oxidation in air, and oxidative dehydrogenation of cyclohexane).…”

Section: Introductionmentioning

confidence: 99%

“…Such techniques have previously been used to investigate the oxidation of bulk Cu and Cu surfaces. [17][18][19][20][21][22][23][24] To obtain size-dependent trends, we study theoretically Cu 4 , Cu 12 and Cu 20 , and their oxides, both in the gas phase and when supported on hydroxylated amorphous alumina (HAA). Experimental validation is provided by X-ray Absorption Near Edge Spectroscopy (XANES) studies on clusters of the same sizes, supported on HAA.…”

Section: Introductionmentioning

confidence: 99%

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Reversing Size‐Dependent Trends in the Oxidation of Copper Clusters through Support Effects

et al. 2017

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Having the ability to tune the oxidation state of Cu nanoparticles is essential for their utility as catalysts. The degree of oxidation that maximizes product yield and selectivity is known to vary, depending on the particular reaction. Using first principles calculations and XANES measurements, we show that for subnanometer sizes in the gas phase, smaller Cu clusters are more resistant to oxidation. However, this trend is reversed upon deposition on an alumina support. We are able to explain this result in terms of strong cluster‐support interactions, which differ significantly for the oxidized and elemental clusters. The stable cluster phases also feature novel oxygen stoichiometries. Our results suggest that one can tune the degree of oxidation of Cu catalysts by optimizing not just their size, but also the support they are deposited on.

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Chemical looping combustion and gasification of swine manure with a Cu-Based oxygen carrier

Domingos,

Abad,

De Las Obras Loscertales

et al. 2025

Chemical Engineering Journal

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Oxidation of ammonia over a copper oxide-containing solid oxygen carrier with oxygen uncoupling capability

Cited by 15 publications

References 18 publications

Ferrierite and Its Delaminated Forms Modified with Copper as Effective Catalysts for NH3-SCO Process

Ferrierite and Its Delaminated Forms Modified with Copper as Effective Catalysts for NH3-SCO Process

Reversing Size‐Dependent Trends in the Oxidation of Copper Clusters through Support Effects

Chemical looping combustion and gasification of swine manure with a Cu-Based oxygen carrier

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