Au/CeO2 metallic monolith catalysts: influence of the metallic substrate

Tejada, Leidy Marcela Martínez; Domínguez, M.I.; Sánz, Oihane; Odriozola, J.A.

doi:10.1007/s13404-013-0102-0

Cited by 18 publications

(5 citation statements)

References 39 publications

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“…In the case of FeCrAl metal support, the thickness and homogeneity of the Al 2 O 3 produced during the initial thermal pretreatment is important but insufficient for every chemical system where precise catalyst formulations are required, as in the case of environmental reactions . In a 500 h stability experiment for preferential CO oxidation operating between 100 and 300 °C, Fe, Cr, and Y migrated from the bulk to the washcoating and there deactivated the catalyst .…”

Section: Catalyst Preparationmentioning

confidence: 99%

“…In a 500 h stability experiment for preferential CO oxidation operating between 100 and 300 °C, Fe, Cr, and Y migrated from the bulk to the washcoating and there deactivated the catalyst . A 22-h preoxidation treatment at 950 °C was insufficient to create an Al 2 O 3 barrier between the metal support and the washcoat, so cations continued to migrate from the bulk . Cr from a FeCrNi support migrated within 24 h on-stream operation after a 650 °C peroxidation step, while migration in FeCrAl was undetected .…”

Section: Catalyst Preparationmentioning

confidence: 99%

“…With Al-Fe pillared bentonites or CeO 2 coatings, cations move between external and protective oxide layers, which is deleterious in the case of precise catalyst formulations. These movements vary with elements, protective coatings, ions, and the process/reaction conditions. , When supported on bentonites, Au blocks Cr in the alloy, while the contrary occurs with CeO 2 as the intermediate layer . In situ combustion synthesis produces Cu-CeO 2 on FeCrAl catalysts for the preferential oxidation of CO.…”

Section: Applications In Emission Controlmentioning

confidence: 99%

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FeCrAl as a Catalyst Support

et al. 2020

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The iron-chromium-aluminum alloy (FeCrAl) is an exceptional support for highly exothermic and endothermic reactions that operate above 700 °C in chemically aggressive environments, where low heat and mass transfer rates limit reaction yield. FeCrAl two-and three-dimensional structured networksmonoliths, foams, and fibersmaximize mass transfer rates, while their remarkable thermal conductivity minimizes hot spots and thermal gradients. Another advantage of the open FeCrAl structure is the low pressure drop due to the high void fraction and regularity of the internal path. The surface Al 2 O 3 layer, formed after an initial thermal oxidation, supports a wide range of metal and metal oxide active phases. The aluminum oxide that adheres to the metal surface protects it from corrosive atmospheres and carbon (carburization), thus allowing FeCrAl to operate at a higher temperature. The top applications are industrial burners, in which compact knitted metal fibers distribute heat over large surface areas, and automotive tail gas converters. Future applications include producing H 2 and syngas from remote natural gas in modular units. This Review summarizes the specific preparation techniques, details process operating conditions and catalyst performance of several classes of reactions, and highlights positive and challenging aspects of FeCrAl.

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Section: Catalyst Preparationmentioning

confidence: 99%

Section: Catalyst Preparationmentioning

confidence: 99%

Section: Applications In Emission Controlmentioning

confidence: 99%

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FeCrAl as a Catalyst Support

et al. 2020

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“…Metals are highly attractive due to their high heat transfer coefficient and several cases, including alloys, have tested up to now. Most of the metallic monolithic structures developed so far are built out of Al-alloyed ferritic stainless steels foils [120][121][122][123][124][125]. However, the almost universal utilization of this alloy within the catalytic community is their use at temperatures well below the optimum service temperature and under hydrogen and carbon-rich atmospheres, resulting in migration of alloy elements to the catalytic layer, brattling its joining to the wall of the structured reactor [122,126].…”

Section: The Use Of Structured Reactors For the Sabatier Reactionmentioning

confidence: 99%

Policies and Motivations for the CO2 Valorization through the Sabatier Reaction Using Structured Catalysts. A Review of the Most Recent Advances

et al. 2018

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The current scenario where the effects of global warming are more and more evident, has motivated different initiatives for facing this, such as the creation of global policies with a clear environmental guideline. Within these policies, the control of Greenhouse Gase (GHG) emissions has been defined as mandatory, but for carrying out this, a smart strategy is proposed. This is the application of a circular economy model, which seeks to minimize the generation of waste and maximize the efficient use of resources. From this point of view, CO2 recycling is an alternative to reduce emissions to the atmosphere, and we need to look for new business models which valorization this compound which now must be considered as a renewable carbon source. This has renewed the interest in known processes for the chemical transformation of CO2 but that have not been applied at industrial level because they do not offer evident profitability. For example, the methane produced in the Sabatier reaction has a great potential for application, but this depends on the existence of a sustainable supply of hydrogen and a greater efficiency during the process that allows maximizing energy efficiency and thermal control to maximize the methane yield. Regarding energy efficiency and thermal control of the process, the use of structured reactors is an appropriate strategy. The evolution of new technologies, such as 3D printing, and the consolidation of knowledge in the structing of catalysts has enabled the use of these reactors to develop a wide range of possibilities in the field. In this sense, the present review presents a brief description of the main policies that have motivated the transition to a circular economy model and within this, to CO2 recycling. This allows understanding, why efforts are being focused on the development of different reactions for CO2 valorization. Special attention to the case of the Sabatier reaction and in the application of structured reactors for such process is paid.

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“…Another issue to take into account when dealing with metallic supports is the fact that the interaction between the elements of the metallic support and the catalytic coating may modify the activity (poisoning or activation) as well as the properties of the protective outer shell, such as its thickness and adhesion to the substrate. − Few articles dealing with FeCrAlloy supports report the migration of alloy elements into coatings made by ZSM-5 zeolite, Au/TiO 2 , Au/CeO 2 , and CuO x /CeO 2 …”

Section: Introductionmentioning

confidence: 99%

Role of Coating-Metallic Support Interaction in the Properties of Electrosynthesized Rh-Based Structured Catalysts

et al. 2014

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Rh-structured catalysts for the catalytic partial oxidation of CH 4 to syngas were prepared by electrosynthesis of Rh-containing hydrotalcite-type (HT) compounds on FeCrAlloy foams followed by calcination at 900 °C. During the calcination the simultaneous decomposition of the layered HT structure and formation of the protective FeCrAlloy outer shell in alumina occurred. Here, we studied the role of the coating-metallic support interaction in the properties of the catalysts after calcination, H 2 reduction, and catalytic tests, by a combination of electron (FEG-SEM/EDS) and synchrotron X-ray (XRF/XRPD and XRF/ XANES) microscopic techniques. The characterization of crystalline phases in the metallic support and coating and distribution of Rh active species was carried out on several samples prepared by modifying the Rh content in the electrolytic solution (Rh/ Mg/Al = 11.0/70.0/19.0, 5.0/70.0/25.0, 0/70.0/30.0 atomic ratio). A sample was also prepared with no aluminum in the electrolytic solution (Rh/Mg/Al = 13.6/86.4/0.0 atomic ratio) and calcined at 550 and 900 °C. The interaction between the elements of the metallic support and the catalytic coating increased the film adhesion during the thermal treatment and catalytic tests and modified the catalyst crystalline phases. A chemical reaction between Al coming from the foam and Mg in the coating occurred during calcination at high temperature leading to the formation of spinel phases in which rhodium is solved, together with some Rh 2 O 3 and Rh 0 . The metallic support was oxidized forming the corundum scale and chromium oxides, moreover ι-Al 2 O 3 was identified. For the Rh 11.0 Mg 70.0 Al 19.0 catalyst the inclusion of Rh in the spinel phase decreased its reducibility in the H 2 pretreatment. The reduction continued during catalytic tests by feeding diluted CH 4 /O 2 /He gas mixtures, evidenced by the catalyst activation. While under concentrated gas mixtures the deactivation occurred, probably by oxidation.

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Au/CeO2 metallic monolith catalysts: influence of the metallic substrate

Cited by 18 publications

References 39 publications

FeCrAl as a Catalyst Support

FeCrAl as a Catalyst Support

Policies and Motivations for the CO2 Valorization through the Sabatier Reaction Using Structured Catalysts. A Review of the Most Recent Advances

Role of Coating-Metallic Support Interaction in the Properties of Electrosynthesized Rh-Based Structured Catalysts

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