Cobalt oxide catalysts for ammonia oxidation activated with cerium and lanthanum

Petryk, J.; Kołakowska, Ewa

doi:10.1016/s0926-3373(99)00099-5

Cited by 61 publications

(36 citation statements)

References 9 publications

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“…22 Earlier work has established that CeO 2 is the most active phase in the catalytic reaction, because it effectively increases O 2 storage capacity, even though noble metals are used as catalysts. 23,24 CeO 2 in a Cu catalyst may be assumed to promote the generation of the active phase of CuO under the conditions of NH 3 oxidation. X-ray powder diffraction confirmed the formation of CuNO 3 and CeO 2 active sites, at least synergistically affecting the Cu-Ce composite catalyst.…”

Section: Resultsmentioning

confidence: 99%

“…Ce stabilizes the washcoat layer, increases the thermal resistance, enhances the catalytic activity of precious metals, and enables the storage of O 2 . [21][22][23][24] However, the feasibility of using a copper (Cu)-Ce composite catalyst to determining the reactive properties of these active metals in the SCO process seldom has been addressed. This work addresses the activity of the Cu-Ce composite catalyst in the oxidation of NH 3 , as determined by various parameters, and its effect on the removal of NH 3 from an effluent stream using the SCO process.…”

Section: M)mentioning

confidence: 99%

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Selective Catalytic Oxidation of Ammonia over Copper-Cerium Composite Catalyst

Lou

Hung

Yang

2004

Journal of the Air & Waste Management Association

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This work considers the oxidation of ammonia (NH 3 ) by selective catalytic oxidation (SCO) over a copper (Cu)-cerium (Ce) composite catalyst at temperatures between 150 and 400°C. A Cu-Ce composite catalyst was prepared by coprecipitation of copper nitrate and cerium nitrate at various molar concentrations. This study also considers how the concentration of influent NH 3 (500 -1000 ppm), the space velocity (72,000 -110,000 hr Ϫ1 ), the relative humidity (12-18%) and the concentration of oxygen (4 -20%) affect the operational stability and the capacity for removing NH 3 . The effects of the O 2 and NH 3 content of the carrier gas on the catalyst's reaction rate also are considered. The experimental results show that the extent of conversion of NH 3 by SCO in the presence of the Cu-Ce composite catalyst was a function of the molar ratio. The NH 3 was removed by oxidation in the absence of Cu-Ce composite catalyst, and ϳ99.2% NH 3 reduction was achieved during catalytic oxidation over the Cu-Ce (6:4, molar/molar) catalyst at 400°C with an O 2 content of 4%. Moreover, the effect of the initial concentration and reaction temperature on the removal of NH 3 in the gaseous phase was also monitored at a gas hourly space velocity of less than 92,000 hr ؊1 .

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Section: Resultsmentioning

confidence: 99%

Section: M)mentioning

confidence: 99%

Selective Catalytic Oxidation of Ammonia over Copper-Cerium Composite Catalyst

Lou

Hung

Yang

2004

Journal of the Air & Waste Management Association

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“…In other words, PtLa/C electrocatalysts are more resistant to the poisoning caused by ethanol intermediate adspecies causing a significant increase of performance with the augment of La oxides/hidroxides content. This behaviour could be attributed to the oxophilic character of La in La(OH) 2 and La 2 O 3 [25].…”

Section: Resultsmentioning

confidence: 98%

“…It is used as support for metals that catalyze reactions such as methanol decomposition, ammonia oxidation, and methane dry reforming [1][2][3][4]. It is also recognized as an active and selective catalyst for several processes [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Ethanol Electrooxidation on Pt with Lanthanum Oxide as Cocatalyst in a DAFC

Santoro

Neto

Forbicini

et al. 2012

International Journal of Electrochemistry

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Electrocatalytic activity toward ethanol electrooxidation of Pt particles in PtLa/C catalysts with different Pt : La ratios has been studied with different electrochemical and spectroscopic techniques, and the results were compared to those of Pt/C catalyst. Significant enhancement in the electrocatalytic activity has been achieved by depositing the Pt particles with lanthanum oxides/hydroxides using an alcohol reduction method. Compared to Pt/C catalyst, PtLa/C materials exhibit a lower onset potential and a higher electron-transfer rate constant for the investigated reaction. These studies illustrate the possibility of utilizing Pt/C with La oxides/ hidroxides as electrocatalyst for direct alcohol fuel cells (DAFCs).

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“…Co 3 O 4 exhibits high activity in oxidation of carbon oxide [3], ammonia [4], methane, and other hydrocarbons [5,6]. It is also well known for its spectacular activity in oxygen reduction reaction (ORR) [7], or low temperature decomposition of N 2 O [8,9].…”

Section: Introductionmentioning

confidence: 99%

Surface oxygen dynamics and H2 oxidation on cobalt spinel surface probed by 18O/16O isotopic exchange and accounted for by DFT molecular modeling: facile interfacial oxygen atoms flipping through transient peroxy intermediate

et al. 2016

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Surface dynamics of reactive oxygen species (ROS) and hydrogen oxidation on cobalt spinel nanocatalyst, faceted predominantly with (100) 2-peroxy unit requires 0.39 eV only, opening an easy pathway for rapid isotopic exchange without explicit formation of energetically more costly oxygen vacancies. The latter may occur effectively at T [ 700°C. The catalytic activity of ROS species was probed by H 2 oxidation reaction. The diatomic ROS reactivity (below 160°C) is characterized by E a = 16 kcal/mol, and for monoatomic species (between 160°C and 300°C) it falls to E a = 9.2 kcal/mol. It was shown that suprafacial dehydroxylation of ROS generated water is energetically less costly (E a = 1.15 eV) than intrafacial dehydroxylation (E a = 1.71 eV) entailing removal of water associated with the lattice oxygen. Thus, the former may operate even at relatively low temperatures (below 300-350°C). The appearance of significant amount of H 2 16 O in the reaction products is related to easy isotopic 18 O/ 16 O scrambling via transient peroxo intermediates, and is not diagnostic of direct involvement of the Mars van Krevelen mechanism.

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Cobalt oxide catalysts for ammonia oxidation activated with cerium and lanthanum

Cited by 61 publications

References 9 publications

Selective Catalytic Oxidation of Ammonia over Copper-Cerium Composite Catalyst

Selective Catalytic Oxidation of Ammonia over Copper-Cerium Composite Catalyst

Ethanol Electrooxidation on Pt with Lanthanum Oxide as Cocatalyst in a DAFC

Surface oxygen dynamics and H2 oxidation on cobalt spinel surface probed by 18O/16O isotopic exchange and accounted for by DFT molecular modeling: facile interfacial oxygen atoms flipping through transient peroxy intermediate

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