Supported and unsupported manganese oxides for catalytic ammonia combustion

Hinokuma, Satoshi; Shimanoe, Hiroki; Kawabata, Yusuke; Kiritoshi, Saaya; Araki, Kento; Machida, Masato

doi:10.1016/j.catcom.2017.11.009

Cited by 14 publications

(5 citation statements)

References 19 publications

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“…The intensity of the diffraction peaks of the activated carbon became weaker, indicating that the diffraction peaks of the activated carbon decreased after loading of manganese onto the activated carbon. It has also been demonstrated that MnO 2 [54] has the best catalytic treatment performance among the various valence states of manganese oxides.…”

Section: Fig 2 Cod Removal Rates Of Different Catalystsmentioning

confidence: 99%

Study on Treatment of Basic Yellow 28 dye Wastewater by Micro-nano Bubble Ozone Catalytic Oxidation

Wang¹,

Sha²,

Wang³

2023

Environmental Engineering Research

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Mn loaded AC (Mn/AC), Cu loaded AC (Cu/AC), and Fe loaded AC (Fe/AC) catalysts were prepared by the impregnation-calcination method, which can be used to degrade Basic Yellow 28 dyes in simulated printing and dyeing wastewater for catalytic ozonation. The catalyst preparation and reaction conditions were optimized with the degradation efficiency of chemical oxygen demand (COD) and the absorbance of some organic compounds under 254 nm UV light (UV254) as indicators. The surface structure, specific surface area, and active component distribution of the catalysts were analyzed by scanning electron microscopy (SEM), nitrogen adsorption, and X-ray diffraction (XRD) characterization. Results indicated that Mn was the best active component, and a catalyst dosage of 3.5 g/L, an initial pH of 9.4, and an initial temperature of 31.7°C were the best reaction parameters to degrade Basic Yellow 28 dyes. After five recycling experiments, the catalysts could retain a relatively stable catalytic effect. Furthermore, this study can be informative for the sustainable development of future catalysts.

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Section: Fig 2 Cod Removal Rates Of Different Catalystsmentioning

confidence: 99%

Study on Treatment of Basic Yellow 28 dye Wastewater by Micro-nano Bubble Ozone Catalytic Oxidation

Wang¹,

Sha²,

Wang³

2023

Environmental Engineering Research

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“…The ideal catalyst should be selective and active in a broad temperature range and should possess high water-tolerance and very low sensitivity to sulphur poisoning. 14,15 In the last decades, several catalytic systems have been proposed for this process, such as supported or unsupported noble metals, [16][17][18] transition metal oxides, 16,[19][20][21] and mixed oxides. [22][23][24][25] In particular, iron [26][27][28] and copper [28][29][30][31] oxides have demonstrated to be active and selective catalysts.…”

Section: Nh3 + 3o2 → 2n2 + 6h2omentioning

confidence: 99%

“…The ideal catalyst should be selective and active in a broad temperature range and should possess high water tolerance and very low sensitivity to sulfur poisoning. , In the past decades, several catalytic systems have been proposed for this process, such as supported or unsupported noble metals, − transition-metal oxides, ,− and mixed oxides. − In particular, iron − and copper − oxides have demonstrated to be active and selective catalysts. On the other hand, Fe and Cu demonstrated to be active and selective species also when encapsulated as ions inside zeolitic frameworks − probably due to the possibility to work in two different oxidation states (Fe 2+ /Fe 3+ and Cu 2+ /Cu + ) …”

Section: Introductionmentioning

confidence: 99%

Finely Iron-Dispersed Particles on β Zeolite from Solvated Iron Atoms: Promising Catalysts for NH₃-SCO

et al. 2019

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Beta zeolite has been functionalized with ca. 2 wt.% Fe to obtain catalysts for the NH3-SCO reaction.Iron deposition was performed on the zeolite surface by solvated metal atom dispersion (SMAD) and ionic-exchange (IE) procedures. ZSM-5 was selected as reference structure known to assure high dispersion of isolated centers when functionalized with iron by IE. Transmission electron microscopy techniques combined with element maps enlightened on the iron-species distribution and dimension on the two zeolites. As expected, highly homogeneous dispersed iron species were present on the ZSM-5 sample prepared by IE, while with Beta zeolite the same deposition method led to the formation of FeOx aggregates (2.5-10 nm) together with isolated iron species. On the other hands, by SMAD approach, well-formed FeOx-nanoparticles ranging 1.0 -4.5 nm were revealed on Beta zeolite.Ammonia oxidation activity (NH3-SCO) on iron-containing zeolites started at ca. 300°C, without no clear effect of the size of Fe on the reaction activity/selectivity. Ammonia conversion regularly increased with temperature with always very high selectivity to dinitrogen (98-100%), without any NOx or N2O formation, on iron containing Beta zeolites, in particular. Only very limited increase of iron particle dimensions were observed on the used Fe-catalysts, in any case.The collected experimental results indicated that not only isolated well-dispersed iron species are associated with high activity and selectivity in the NH3-SCO reaction. SMAD-derived iron nanoparticles worked with excellent performances in the ammonia oxidation reaction with high activity in terms of conversion, selectivity to dinitrogen, and stability.

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“…The apparent reason for this was that Mn-Bi-O system performed optimally under an excess of O 2 , requiring its removal downstream and significantly increasing the costs. In contrast, the use of stoichiometric reactant amounts would likely have had a negative effect on the catalyst stability, as transition metal-based catalysts are known to suffer from deactivation due to over-reduction of the active phase [15,[24][25][26][27] -a key limitation of this class of materials.…”

Section: Introductionmentioning

confidence: 99%

Low‐Valent Manganese Atoms Stabilized on Ceria for Nitrous Oxide Synthesis

et al. 2023

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Nitrous oxide, N2O, exhibits unique reactivity in oxidation catalysis, but the high manufacturing costs limit its prospective uses. Direct oxidation of ammonia, NH3, to N2O can ameliorate this issue but its implementation is thwarted by suboptimal catalyst selectivity and stability, and the lack of established structure–performance relationships. Systematic and controlled material nanostructuring offers an innovative approach for advancement in catalyst design. Herein low‐valent manganese atoms stabilized on ceria, CeO2, are discovered as the first stable catalyst for NH3 oxidation to N2O, exhibiting two‐fold higher productivity than the state‐of‐the‐art. Detailed mechanistic, computational and kinetic studies reveal CeO2 as the mediator of oxygen supply, while undercoordinated manganese species activate O2 and facilitate N2O evolution via NN bond formation between nitroxyl, HNO, intermediates. Synthesis via simple impregnation of a small metal quantity (1 wt%) predominantly generates isolated manganese sites, while full atomic dispersion is achieved upon redispersion of sporadic oxide nanoparticles during reaction, as confirmed by advanced microscopic analysis and electron paramagnetic resonance spectroscopy. Subsequently, manganese speciation is maintained, and no deactivation is observed over 70 h on stream. CeO2‐supported isolated transition metals emerge as a novel class of materials for N2O production, encouraging future studies to evaluate their potential in selective catalytic oxidations at large.

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Supported and unsupported manganese oxides for catalytic ammonia combustion

Cited by 14 publications

References 19 publications

Study on Treatment of Basic Yellow 28 dye Wastewater by Micro-nano Bubble Ozone Catalytic Oxidation

Study on Treatment of Basic Yellow 28 dye Wastewater by Micro-nano Bubble Ozone Catalytic Oxidation

Finely Iron-Dispersed Particles on β Zeolite from Solvated Iron Atoms: Promising Catalysts for NH₃-SCO

Low‐Valent Manganese Atoms Stabilized on Ceria for Nitrous Oxide Synthesis

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Supported and unsupported manganese oxides for catalytic ammonia combustion

Cited by 14 publications

References 19 publications

Study on Treatment of Basic Yellow 28 dye Wastewater by Micro-nano Bubble Ozone Catalytic Oxidation

Study on Treatment of Basic Yellow 28 dye Wastewater by Micro-nano Bubble Ozone Catalytic Oxidation

Finely Iron-Dispersed Particles on β Zeolite from Solvated Iron Atoms: Promising Catalysts for NH3-SCO

Low‐Valent Manganese Atoms Stabilized on Ceria for Nitrous Oxide Synthesis

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Finely Iron-Dispersed Particles on β Zeolite from Solvated Iron Atoms: Promising Catalysts for NH₃-SCO