An efficient robust fluorite CeZrO<sub>4−δ</sub> oxide catalyst for the eco-benign synthesis of styrene

Kaliyappan, Periyasamy; Aswathy, Venugopalan T.; kumar, Venugopal Ashok; Manikandan, Marimuthu; Shukla, Rakesh; Tyagi, A. K.; Raja, Thirumalaiswamy

doi:10.1039/c4ra12355g

Cited by 22 publications

(5 citation statements)

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“…XRD pattern was recorded for Pdx (x=1, 3 and 5, wt % of Pd loading) and R−Pd5 (where R stands for reduced), and the results are shown in Figure . XRD pattern of all catalysts show six distinct peaks at 29.1, 33.6, 48.5, 57.6, 71.2 and 78.5 deg corresponds to (111), (200), (220), (311), (400) and (331) facets, respectively, suggesting the fluorite structure . The catalyst preparation method with glycine in stoichiometric ratio was used in literature for synthesis of pyrochlore, wherein the ordering of cation resulting in formation of pyrochlore; however, in the present case, no peaks were observed for pyrochlore.…”

Section: Resultsmentioning

confidence: 58%

“…Ceria zirconia mixed oxide and solid solution exhibit high redox properties as well as thermal stability which make it a better heterogeneous catalyst compared to pure ceria . Recently Periyasamy et al reported on eco‐friendly synthesis of styrene using robust fluorite CeZrO 4‐δ catalyst . By considering the merits of redox and robust fluorite structured CeZrO 4‐δ , and continuation of our work in exploring new catalytic materials in organic transformations, we evaluated and demonstrated the use of CeZrO 4‐δ as a redox support to Pd for Suzuki cross coupling reaction (Scheme ).…”

Section: Introductionmentioning

confidence: 98%

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Palladium Supported on Fluorite Structured Redox CeZrO_4-δfor Heterogeneous Suzuki Coupling in Water: A Green Protocol

et al. 2016

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Pd on redox CeZrO4‐δ catalysts was prepared, characterized and their activity was evaluated for Suzuki coupling reaction in water under reflux condition. Fresh and reduced form of 5 % Pd (R−Pd5) on CeZrO4‐δ catalyst exhibited 100 % conversion in 2.5 and 1 h, respectively. R−Pd5 shows significant activity for wide range of substrate compatibility and for less reactive aryl bromides too. The mechanistic investigations proved the important role of redox CeZrO4‐δ support on the catalytic activity. It was observed that the presence of oxygen vacancy along with Ce3+ enhances the activity. 1 wt % Pd photodeposited on pre‐reduced CeZrO4‐δ support requires a mere 20 min. for 100 % conversion of Suzuki coupling. Effect of metal dispersion and particle size on catalytic activity is also discussed. High Pd dispersion with small particle size (4±1 nm), particle size preservation after reaction, strong metal‐support interaction and no leaching fully suggest the heterogeneous mechanism is operative for Suzuki coupling on 1 wt % Pd photodeposited on reduced CeZrO4‐δ support. Present work hints the possibility of achieving high conversion for Suzuki reaction with very small amount of Pd through better dispersion by taking advantage of redox support and in water.

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Section: Resultsmentioning

confidence: 58%

Section: Introductionmentioning

confidence: 98%

Palladium Supported on Fluorite Structured Redox CeZrO_4-δfor Heterogeneous Suzuki Coupling in Water: A Green Protocol

et al. 2016

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“…1. below, in the case of a representative NiOx/Ce0.5Zr0.5O2 sample, the continues synthesis under supercritical conditions leads to a satisfactory surface development of mainly mesoporous character, confirmed by a characteristic shape of the corresponding adsorption-desorption hysteresis loop (type IV, according to IUPAC classification [19]). The mesopores are most probably of cylindrical shapes for all investigated fresh samples and quite uniform in diameters, ranging from ca.…”

Section: Textural Propertiesmentioning

confidence: 83%

Role of CeO₂-ZrO₂Support for Structural, Textural and Functional Properties of Ni-based Catalysts Active in Dry Reforming of Methane

et al. 2019

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Positive environmental and technological contexts make dry methane reforming (DMR) an extensively studied reaction. During this process two main greenhouse gases CH4 and CO2 can be simultaneously converted into syngas – a mixture of CO and H2. Supported-nickel is one of the most frequently applied DMR catalysts. Their activity depends mainly on Ni concentration, kind of its precursor and a deposition method. As DMR is a demanding high-temperature reaction, it requires not only an active but first a very stable catalyst. Structural, textural and functional properties of such support remain thus of crucial efficiency. Main aim of this work was to elucidate how the synthesis of CeO2-ZrO2 support obtained by supercritical fluid method (i.e. at temperature of 400°C under a pressure of 25 MPa), can influence the properties of Ni-based DMR catalysts. The supports of various compositions (CeO2 content from 100 to 0 %), subsequently calcined at 800°C for 6h in air have been analyzed. Nickel was deposited from nitrate(V) precursor via classical wet impregnation. The final catalysts have been characterized structurally (XRD, RS), texturally (BET, SEM) and functionally (UV/Vis-DR, XPS). Catalytic tests in dry methane reforming reaction have been performed to determine activity and stability of the synthesized samples.

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“…The band at ~300 cm −1 denotes change in the position of the oxygen atom from their ideal fluorite structure. The broad band at 620 cm −1 is due to the presence of oxygen vacancy in the fluorite phase which causes defects sites in Ce–Zr oxides for the activity of the catalyst [ 45 , 50 ]; this band is more prominent for the fresh support. Moreover, the fact that the main peak is broader for the fresh material as it is observed in Figure 1 b is an indication of smaller crystallite size in CZ-fresh material.…”

Section: Resultsmentioning

confidence: 99%

High Catalytic Efficiency of a Nanosized Copper-Based Catalyst for Automotives: A Physicochemical Characterization

Beobide

Moschovi²,

Mathioudakis³

et al. 2022

Molecules

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The global trend in restrictions on pollutant emissions requires the use of catalytic converters in the automotive industry. Noble metals belonging to the platinum group metals (PGMs, platinum, palladium, and rhodium) are currently used for autocatalysts. However, recent efforts focus on the development of new catalytic converters that combine high activity and reduced cost, attracting the interest of the automotive industry. Among them, the partial substitution of PGMs by abundant non-PGMs (transition metals such as copper) seems to be a promising alternative. The PROMETHEUS catalyst (PROM100) is a polymetallic nanosized copper-based catalyst for automotives prepared by a wet impregnation method, using as a carrier an inorganic mixed oxide (CeO2-ZrO2) exhibiting elevated oxygen storage capacity. On the other hand, catalyst deactivation or ageing is defined as the process in which the structure and state of the catalyst change, leading to the loss of the catalyst’s active sites with a subsequent decrease in the catalyst’s performance, significantly affecting the emissions of the catalyst. The main scope of this research is to investigate in detail the effect of ageing on this low-cost, effective catalyst. To that end, a detailed characterization has been performed with a train of methods, such as SEM, Raman, XRD, XRF, BET and XPS, to both ceria–zirconia mixed inorganic oxide support (CZ-fresh and -aged) and to the copper-based catalyst (PROM100-fresh and -aged), revealing the impact of ageing on catalytic efficiency. It was found that ageing affects the Ce–Zr mixed oxide structure by initiating the formation of distinct ZrO2 and CeO2 structures monitored by Raman and XRD. In addition, it crucially affects the morphology of the sample by reducing the surface area by a factor of nearly two orders of magnitude and increasing particle size as indicated by BET and SEM due to sintering. Finally, the Pd concentration was found to be considerably reduced from the material’s surface as suggested by XPS data. The above-mentioned alterations observed after ageing increased the light-off temperatures by more than 175 °C, compared to the fresh sample, without affecting the overall efficiency of the catalyst for CO and CH4 oxidation reactions. Metal particle and CeZr carrier sintering, washcoat loss as well as partial metal encapsulation by Cu and/or CeZrO4 are identified as the main causes for the deactivation after hydrothermal ageing.

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An efficient robust fluorite CeZrO_4−δ oxide catalyst for the eco-benign synthesis of styrene

Abstract: The catalytic activities of CeO2, ZrO2, (PH)-CeO2/ZrO2 and fluorite CeZrO4−δ oxides were reported for the oxidative dehydrogenation of ethyl benzene to styrene using O2, air and CO2 as oxidants. CeZrO4−δ accounted for a 47% styrene yield under optimized reaction conditions.

Cited by 22 publications

References 39 publications

Palladium Supported on Fluorite Structured Redox CeZrO_4-δfor Heterogeneous Suzuki Coupling in Water: A Green Protocol

Palladium Supported on Fluorite Structured Redox CeZrO_4-δfor Heterogeneous Suzuki Coupling in Water: A Green Protocol

Role of CeO₂-ZrO₂Support for Structural, Textural and Functional Properties of Ni-based Catalysts Active in Dry Reforming of Methane

High Catalytic Efficiency of a Nanosized Copper-Based Catalyst for Automotives: A Physicochemical Characterization

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An efficient robust fluorite CeZrO4−δ oxide catalyst for the eco-benign synthesis of styrene

Abstract: The catalytic activities of CeO2, ZrO2, (PH)-CeO2/ZrO2 and fluorite CeZrO4−δ oxides were reported for the oxidative dehydrogenation of ethyl benzene to styrene using O2, air and CO2 as oxidants. CeZrO4−δ accounted for a 47% styrene yield under optimized reaction conditions.

Cited by 22 publications

References 39 publications

Palladium Supported on Fluorite Structured Redox CeZrO4-δfor Heterogeneous Suzuki Coupling in Water: A Green Protocol

Palladium Supported on Fluorite Structured Redox CeZrO4-δfor Heterogeneous Suzuki Coupling in Water: A Green Protocol

Role of CeO2-ZrO2Support for Structural, Textural and Functional Properties of Ni-based Catalysts Active in Dry Reforming of Methane

High Catalytic Efficiency of a Nanosized Copper-Based Catalyst for Automotives: A Physicochemical Characterization

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An efficient robust fluorite CeZrO_4−δ oxide catalyst for the eco-benign synthesis of styrene

Palladium Supported on Fluorite Structured Redox CeZrO_4-δfor Heterogeneous Suzuki Coupling in Water: A Green Protocol

Palladium Supported on Fluorite Structured Redox CeZrO_4-δfor Heterogeneous Suzuki Coupling in Water: A Green Protocol

Role of CeO₂-ZrO₂Support for Structural, Textural and Functional Properties of Ni-based Catalysts Active in Dry Reforming of Methane