Preparation, characterization and catalytic performance of Ag-modified mesoporous TiO 2 in low-temperature selective ammonia oxidation into nitrogen and water vapour

Jabłońska, Magdalena; Ciptonugroho, Wirawan; Góra‐Marek, Kinga; Al‐Shaal, Mohammad G.; Palkovits, Regina

doi:10.1016/j.micromeso.2017.02.070

Cited by 22 publications

(7 citation statements)

References 44 publications

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“…1 wt % CuO–Fe 2 O 3 prepared by impregnation gave less NH 3 conversion and N 2 selectivity compared to the coprecipitated 1 wt % CuO–Fe 2 O 3 (Figure S8c), suggesting that atomic Cu–O–Fe in the lattice promotes both oxidation ability and NO adsorption and thus improving the N 2 yield. Compared to other catalyst systems in the literature, ,− the atomic Cu–O–Fe catalyst achieved the highest N 2 productivity of Cu-based catalysts, even higher than some noble metal catalysts between 523 and 623 K (Figure d). Under realistic NH 3 slip conditions (1000 ppm of NH 3 and a WHSV of 120 mL NH3 ·h –1 ·g –1 ), 100% NH 3 conversion and 99% N 2 selectivity are achieved at 573 K (Figure e), suppressing most of the reported catalysts (Table S5).…”

Section: Resultsmentioning

confidence: 99%

Designing Reactive Bridging O^2– at the Atomic Cu–O–Fe Site for Selective NH₃ Oxidation

et al. 2022

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Surface oxidation chemistry involves the formation and breaking of metal−oxygen (M−O) bonds. Ideally, the M−O bonding strength determines the rate of oxygen absorption and dissociation. Here, we design reactive bridging O 2− species within the atomic Cu−O−Fe site to accelerate such oxidation chemistry. Using in situ X-ray absorption spectroscopy at the O K-edge and density functional theory calculations, it is found that such bridging O 2− has a lower antibonding orbital energy and thus weaker Cu− O/Fe−O strength. In selective NH 3 oxidation, the weak Cu−O/ Fe−O bond enables fast Cu redox for NH 3 conversion and direct NO adsorption via Cu−O−NO to promote N−N coupling toward N 2 .As a result, 99% N 2 selectivity at 100% conversion is achieved at 573 K, exceeding most of the reported results. This result suggests the importance to design, determine, and utilize the unique features of bridging O 2− in catalysis.

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Section: Resultsmentioning

confidence: 99%

Designing Reactive Bridging O^2– at the Atomic Cu–O–Fe Site for Selective NH₃ Oxidation

et al. 2022

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“…Moreover, NO selectivity was not affected by the different O 2 content during NH 3 -SCO. TiO 2 anatase is the most common catalyst support, while the catalytic properties are affected by the properties of the support (i.e., anatase versus rutile) [84]. NH 3 -SCO over Cu/TiSnO 2 and Cu/TiO 2 (10.5-11.8 wt.% of Cu) was reported to follow the i-SCR and imide (-NH) mechanisms, respectively [85].…”

Section: Other Metal Oxidesmentioning

confidence: 99%

A Comparative Mini-Review on Transition Metal Oxides Applied for the Selective Catalytic Ammonia Oxidation (NH3-SCO)

Jabłońska

Robles

2022

Materials

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The selective catalytic oxidation of NH3 (NH3-SCO) into N2 and H2O is an efficient technology for NH3 abatement in diesel vehicles. However, the catalysts dedicated to NH3-SCO are still under development. One of the groups of such catalysts constituted transition metal-based catalysts, including hydrotalcite-derived mixed metal oxides. This class of materials is characterized by tailored composition, homogenously dispersed mixed metal oxides, exhibiting high specific surface area and thermal stability. Thus, firstly, we give a short introduction to the structure and composition of hydrotalcite-like materials and their applications in NH3-SCO. Secondly, an overview of other transition metal-based catalysts reported in the literature is given, following a comparison of both groups. The challenges in NH3-SCO applications are provided, while the reaction mechanisms are discussed for particular systems.

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“…Significantly higher N 2 selectivity was obtained over Ag/TiO 2 (91-99% at 180-240 • C). Jabło ńska et al [82] compared commercial TiO 2 with mesoporous TiO 2 (prepared by evaporation induced self-assembly (EISA)) as support in NH 3 -SCO. The activity and N 2 selectivity were favored over (1.5 wt.%)Ag-doped mesoporous TiO 2 (calcined at 600 • C, with predominant anatase phase).…”

Section: Ag-based Catalystsmentioning

confidence: 99%

Progress on Noble Metal-Based Catalysts Dedicated to the Selective Catalytic Ammonia Oxidation into Nitrogen and Water Vapor (NH3-SCO)

Jabłońska

2021

Molecules

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A recent development for selective ammonia oxidation into nitrogen and water vapor (NH3-SCO) over noble metal-based catalysts is covered in the mini-review. As ammonia (NH3) can harm human health and the environment, it led to stringent regulations by environmental agencies around the world. With the enforcement of the Euro VI emission standards, in which a limitation for NH3 emissions is proposed, NH3 emissions are becoming more and more of a concern. Noble metal-based catalysts (i.e., in the metallic form, noble metals supported on metal oxides or ion-exchanged zeolites, etc.) were rapidly found to possess high catalytic activity for NH3 oxidation at low temperatures. Thus, a comprehensive discussion of property-activity correlations of the noble-based catalysts, including Pt-, Pd-, Ag- and Au-, Ru-based catalysts is given. Furthermore, due to the relatively narrow operating temperature window of full NH3 conversion, high selectivity to N2O and NOx as well as high costs of noble metal-based catalysts, recent developments are aimed at combining the advantages of noble metals and transition metals. Thus, also a brief overview is provided about the design of the bifunctional catalysts (i.e., as dual-layer catalysts, mixed form (mechanical mixture), hybrid catalysts having dual-layer and mixed catalysts, core-shell structure, etc.). Finally, the general conclusions together with a discussion of promising research directions are provided.

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Preparation, characterization and catalytic performance of Ag-modified mesoporous TiO 2 in low-temperature selective ammonia oxidation into nitrogen and water vapour

Cited by 22 publications

References 44 publications

Designing Reactive Bridging O^2– at the Atomic Cu–O–Fe Site for Selective NH₃ Oxidation

Designing Reactive Bridging O^2– at the Atomic Cu–O–Fe Site for Selective NH₃ Oxidation

A Comparative Mini-Review on Transition Metal Oxides Applied for the Selective Catalytic Ammonia Oxidation (NH3-SCO)

Progress on Noble Metal-Based Catalysts Dedicated to the Selective Catalytic Ammonia Oxidation into Nitrogen and Water Vapor (NH3-SCO)

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Preparation, characterization and catalytic performance of Ag-modified mesoporous TiO 2 in low-temperature selective ammonia oxidation into nitrogen and water vapour

Cited by 22 publications

References 44 publications

Designing Reactive Bridging O2– at the Atomic Cu–O–Fe Site for Selective NH3 Oxidation

Designing Reactive Bridging O2– at the Atomic Cu–O–Fe Site for Selective NH3 Oxidation

A Comparative Mini-Review on Transition Metal Oxides Applied for the Selective Catalytic Ammonia Oxidation (NH3-SCO)

Progress on Noble Metal-Based Catalysts Dedicated to the Selective Catalytic Ammonia Oxidation into Nitrogen and Water Vapor (NH3-SCO)

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Designing Reactive Bridging O^2– at the Atomic Cu–O–Fe Site for Selective NH₃ Oxidation

Designing Reactive Bridging O^2– at the Atomic Cu–O–Fe Site for Selective NH₃ Oxidation