Ce0.67Fe0.33O2−δ and Ce0.65Fe0.33Pt0.02O2−δ: New water gas shift (WGS) catalysts

Mahadevaiah, N.; Singh, Preetam; Mukri, Bhaskar Devu; Parida, Sanjit Kumar; Hegde, M. S.

doi:10.1016/j.apcatb.2011.08.016

Cited by 25 publications

(6 citation statements)

References 37 publications

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“…Thus, the catalysts prepared via the deposition-precipitation route, due to their anti-sintering behavior, are suitable for high temperature WGS (300-350 • C) while the impregnated catalysts are effective for low temperature operation. WGS kinetics have also been investigated over Ce 0.67 Fe 0.33 O 2-δ and Ce 0.65 Fe 0.33 Pt 0.02 O 2-δ solid solutions prepared by the sonication method [103] under a 3.8% CO, 23% H 2 O, 73.3% N 2 reaction mixture at GHSV = 55,900 h −1 . The Pt-free catalyst displayed a good activity for WGS reaction at moderate temperatures, ascribable to the sufficient CO adsorption properties of iron.…”

Section: Rare Earth and Transition Metals-promoted Catalystsmentioning

confidence: 99%

Platinum Based Catalysts in the Water Gas Shift Reaction: Recent Advances

Palma

Ruocco

Cortese

et al. 2020

Metals

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The water gas shift (WGS) is an equilibrium exothermic reaction, whose corresponding industrial process is normally carried out in two adiabatic stages, to overcome the thermodynamic and kinetic limitations. The high temperature stage makes use of iron/chromium-based catalysts, while the low temperature stage employs copper/zinc-based catalysts. Nevertheless, both these systems have several problems, mainly dealing with safety issues and process efficiency. Accordingly, in the last decade abundant researches have been focused on the study of alternative catalytic systems. The best performances have been obtained with noble metal-based catalysts, among which, platinum-based formulations showed a good compromise between performance and ease of preparation. These catalytic systems are extremely attractive, as they have numerous advantages, including the feasibility of intermediate temperature (250–400 °C) applications, the absence of pyrophoricity, and the high activity even at low loadings. The particle size plays a crucial role in determining their catalytic activity, enhancing the performance of the nanometric catalytic systems: the best activity and stability was reported for particle sizes < 1.7 nm. Moreover the optimal Pt loading seems to be located near 1 wt%, as well as the optimal Pt coverage was identified in 0.25 ML. Kinetics and mechanisms studies highlighted the low energy activation of Pt/Mo2C-based catalytic systems (Ea of 38 kJ·mol−1), the associative mechanism is the most encountered on the investigated studies. This review focuses on a selection of recent published articles, related to the preparation and use of unstructured platinum-based catalysts in water gas shift reaction, and is organized in five main sections: comparative studies, kinetics, reaction mechanisms, sour WGS and electrochemical promotion. Each section is divided in paragraphs, at the end of the section a summary and a summary table are provided.

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Section: Rare Earth and Transition Metals-promoted Catalystsmentioning

confidence: 99%

Platinum Based Catalysts in the Water Gas Shift Reaction: Recent Advances

Palma

Ruocco

Cortese

et al. 2020

Metals

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“…Compared to Ce with crustal abundance of 0.3 ppm (the number of atoms of the element per 1 million atoms of the Earth’s crust), Zr (132 ppm) is much more abundant and its supply risk is relatively low . Recently, a new class of oxygen-storage materials comprising CeO 2 and other transition-metal oxides have been proposed. − Some of these are composites consisting of components which provide an oxygen gateway and an oxygen reservoir when combined in the same system. A typical example is CeO 2 -grafted Fe 2 O 3 , which comprises several CeO 2 grains intimately bound onto the surface of Fe 2 O 3 via Ce–O–Fe interfacial linkages .…”

Section: Introductionmentioning

confidence: 99%

CeO₂-Grafted Mn–Fe Oxide Composites as Alternative Oxygen-Storage Materials for Three-Way Catalysts: Laboratory and Chassis Dynamometer Tests

Machida

Ueno

Omura

et al. 2017

Ind. Eng. Chem. Res.

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A CeO 2 -grafted MnFeO y (CeO 2 /MnFeO y ) has been developed as a substitute for the oxygen-storage CeO 2 material in three-way catalysts. In the CeO 2 / MnFeO y composite, CeO 2 grains were intimately bound to the surface of the MnFeO y solid solution, which adopted an α-Mn 2 O 3 -type structure. Because the surface-grafted CeO 2 acts as an oxygen gateway and MnFeO y acts as an oxygen reservoir, the combination of these oxides has a synergistic effect leading to the fast release and storage of a larger amount of oxygen compared with the separate constituents. The catalytic and oxygen release and storage performances of CeO 2 /MnFeO y were superior to those of CeO 2 /Fe 2 O 3 in a previous study and were correlated to the contribution of Mn in the redox cycles. Finally, a real-sized honeycomb catalyst containing CeO 2 /MnFeO y was developed and tested using a vehicle driven on a chassis dynamometer in the JC08 (hot start) mode for gasoline engine vehicles (Japanese-type approval test cycle) and compared with a reference honeycomb catalyst containing CeO 2 . Despite a 30% decrease in the amount of CeO 2 , the developed honeycomb catalyst demonstrated high conversions of NO x , CO, and total hydrocarbons that were comparable with those of the reference honeycomb catalyst.

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“…176 Much higher activity for the WGS reaction is noticed over a Ce 0.65 Fe 0.33 Pt 0.02 O 2Àd catalyst, compared to Ce 0.67 Fe 0.33 O 2Àd , due to the synergistic interaction of Pt 4+ with Ce 4+ and Fe 3+ ions. 177 Ce 0.95 Ru 0.05 O 2Àd prepared by the hydrothermal method shows a low activation energy and high conversion rates at low temperatures and 100% H 2 selectivity is observed over this catalyst. 178 A sonochemically synthesized Ce 0.65 Fe 0.33 Pd 0.02 O 2Àd catalyst is highly active for water gas shi reaction with reaction rate of 27.2 mmol g À1 s À1 and activation energy of 46.4 kJ mol À1 .…”

Section: Water Gas Shift Reactionmentioning

confidence: 95%

Noble metal ions in CeO₂ and TiO₂: synthesis, structure and catalytic properties

Bera

Hegde

2015

RSC Adv.

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In past four decades, CeO 2 has been recognized as an attractive material in the area of auto exhaust catalysis because of its unique redox properties. In presence of CeO 2 , catalytic activity of noble metals supported on Al 2 O 3 gets enhanced due to higher dispersion of noble metals in their ionic form. In last several years, we have been exploring an entirely new approach of dispersing noble metal ions on CeO 2 and TiO 2 matrices for redox catalysis. In this article, dispersing of noble metal ions by solution combustion as well as other methods over CeO 2 and TiO 2 resulting mainly in −δ (M = Pd, Pt, Rh and Ru) catalysts, structure of these materials, their catalytic properties toward different types of catalysis, structure−property relation and mechanism of catalytic reactions are reviewed. In these catalysts, noble metal ions are incorporated into substrate matrix to a certain limit in a solid solution form. Lower valent noble metal ion substitution in CeO 2 and TiO 2 creates noble metal ionic sites and oxide ion vacancies that act as adsorption sites for redox catalysis. It has been demonstrated that these new generation noble metal ionic catalysts (NMIC) have been found to be catalytically more active than conventional respective nano crystalline noble metal catalysts dispersed on oxide supports. 5 at.% and hence, substitution of only 1−2 at.% noble metal ion in CeO 2 is sufficient to develop a catalyst. The underlying principle of doping aliovalent metal ions into CeO 2 or TiO 2 lattice is to retain their parent structures. In this sense, new-age advanced catalysts such as Ce 1−x M x O 2−δ (M = Pd, Pt, Rh, Cu, Ag and Au), Ce 1−x−y A x M y O 2−δ (A = Ti, Zr, Sn and Fe; M = Pt and Pd) and Ti 1−x M x O 2−δ (M = Pd, Pt, Rh and Ru) retaining their parent fluorite and anatase structures have been prepared in our laboratory employing solution combustion method. 20−23 Thus, synthesis of these single phase oxides is a new conceptwhich is the basis of metal ion catalysts. In these catalysts, noble metal ions and corresponding oxide ion vacancies are supposed to be the active sites. Since, the adsorption sites in these catalysts are noble metal ions such as Pd 2+ , Pt 2+ , Rh 3+ and Ru 4+ , we have named these materials as noble metal ionic catalysts (NMIC). In last several years, we have been studying several exhaust catalytic reactions such as NO reduction, CO and hydrocarbon oxidation, selective catalytic reduction of NO, three-way catalytic reaction, water gas shift (WGS) reaction, preferential oxidation of CO (CO−PROX), H 2 + O 2 recombination reaction, hydrogenation and Heck reaction over these noble metal ionic catalysts and it has been demonstrated that these catalysts are much more active for several catalytic reactions compared to other conventional supported metal catalysts. In this review, at first, we mainly discuss about background, synthesis and characterization of these noble metal ionic catalysts (NMIC). Then we emphasize on our detailed work related to exhaust catalysis comparing activities with t...

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Ce0.67Fe0.33O2−δ and Ce0.65Fe0.33Pt0.02O2−δ: New water gas shift (WGS) catalysts

Cited by 25 publications

References 37 publications

Platinum Based Catalysts in the Water Gas Shift Reaction: Recent Advances

Platinum Based Catalysts in the Water Gas Shift Reaction: Recent Advances

CeO₂-Grafted Mn–Fe Oxide Composites as Alternative Oxygen-Storage Materials for Three-Way Catalysts: Laboratory and Chassis Dynamometer Tests

Noble metal ions in CeO₂ and TiO₂: synthesis, structure and catalytic properties

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Ce0.67Fe0.33O2−δ and Ce0.65Fe0.33Pt0.02O2−δ: New water gas shift (WGS) catalysts

Cited by 25 publications

References 37 publications

Platinum Based Catalysts in the Water Gas Shift Reaction: Recent Advances

Platinum Based Catalysts in the Water Gas Shift Reaction: Recent Advances

CeO2-Grafted Mn–Fe Oxide Composites as Alternative Oxygen-Storage Materials for Three-Way Catalysts: Laboratory and Chassis Dynamometer Tests

Noble metal ions in CeO2 and TiO2: synthesis, structure and catalytic properties

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Product

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CeO₂-Grafted Mn–Fe Oxide Composites as Alternative Oxygen-Storage Materials for Three-Way Catalysts: Laboratory and Chassis Dynamometer Tests

Noble metal ions in CeO₂ and TiO₂: synthesis, structure and catalytic properties