Effect of calcination temperature on the structure and catalytic performance of copper–ceria mixed oxide catalysts in phenol hydroxylation

Amadine, Othmane; Essamlali, Younes; Fihri, Aziz; Larzek, Mohamed; Zahouily, Mohamed

doi:10.1039/c7ra00734e

Cited by 76 publications

(41 citation statements)

References 60 publications

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“…Two different O species with peaks centered around 528 eV and 530 eV were observed. The first one is characteristic of the lattice oxygen forming the fluorite structure with cerium, whereas the second one can be attributed to the oxygen bound to carbon components 44 . This result is in agreement with C 1s XPS spectrum, which is exhibited in Figure 4C.…”

Section: Resultssupporting

confidence: 87%

CeO₂ and CeO₂:Pr nanocrystalline powders prepared by the polymeric precursor method: Yellow and red pigments with tunable color

et al. 2020

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The development of stable and reproducible inorganic pigments is noteworthy for industrial applications mainly considering more intense shades and low toxicity. Among the various candidates to substitute non‐hazardous red and yellow pigments, CeO2 and CeO2:Pr have been attracting attention because of their opacity and high‐temperature stability besides being environmental‐friendly and health‐friendly. In this study, nanostructured CeO2 and CeO2:Pr samples were synthesized using the polymeric precursor method and structural and optical characterizations were performed. Scanning electron microscopy reveals the morphology of CeO2 nanoparticles in which the particle size ranges from 22 to 28 nm as a function of the annealing temperature. Pr‐doping does not show influence on the particle size. XRD results show that CeO2 and CeO2:Pr samples crystallize in the cubic fluorite lattice with Fm3m space group. Raman spectra show the fluorite F2g mode, confirming the XRD results. With Pr‐doping and the annealing of the samples, two bands are observed between 550 and 600 cm−1, which are related to the defects in the fluorite structure associated with oxygen vacancies. XPS spectra reveal an increase in the ratio of Ce3+ ions depending on the annealing temperature and Pr‐doping. This increase is associated with the carbon removal from the lattice by annealing. This behavior causes a change in the hue of the powders as the annealing temperature increases. According to diffuse reflectance and colorimetric measurements, CeO2 shows a light‐yellow color due to the O 2pCe 4f transitions whose b* parameter mainly decreases with annealing, becoming almost white. The CeO2:Pr sample exhibits a red‐orange color because of the electronic transitions between 4f2 → 5d1 states of Pr3+. Upon annealing, L* and b* parameters decrease, resulting in a red‐brown shade. The charge compensation or charge transfer is responsible for the modification of the hue of these pigments.

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Section: Resultssupporting

confidence: 87%

CeO₂ and CeO₂:Pr nanocrystalline powders prepared by the polymeric precursor method: Yellow and red pigments with tunable color

et al. 2020

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“…Employing the used catalyst, the above test reaction was performed again under the same conditions. As shown in Figure , the reused catalyst showed only slight deactivation after five cycles, which might have been caused by gradual poisoning of the catalyst and block of its pores by tar formed during reaction . This result showed that the CuMgFe–LDHs had good reusability and potential industrial value in phenol hydroxylation.…”

Section: Resultsmentioning

confidence: 99%

Facile Synthesis of CuMgFe Layered Double Hydroxides for Efficient Catalytic Phenol Hydroxylation under Mild Conditions

Shen

Liang

et al. 2020

ChemistrySelect

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A series of CuMgFe layered double hydroxides (denoted as X/CuMgFe–LDHs) with different Cu contents were synthesized by co‐precipitation as catalysts for phenol hydroxylation under mild conditions. The as‐prepared samples were analyzed by X‐ray diffraction (XRD), scanning electron microscopy (SEM), inductively coupled plasma emission spectroscopy (ICP‐ES), N2 adsorption–desorption, Fourier transform infrared (FT‐IR), thermogravimetric differential scanning calorimetry (TG‐DSC), X‐ray photoelectron spectroscopy (XPS) and hydrogen temperature‐programmed reduction (H2‐TPR) to investigate the morphologies and physicochemical properties. As presented by the characterization results, introducing a certain amount of copper not only increased the amount of active metal centers but also formed more oxygen vacancies and lattice oxygen to promote electron transport between the double layers in LDHs. However, the excess copper would significantly disrupt the X/CuMgFe–LDH framework, declining the activity. Therefore, the 20/CuMgFe–LDH sample presented the best catalytic performance among all the catalysts in terms of activity, which was correlated with the layered structure, low‐temperature reducibility, oxygen species and low Cu+/Cu2+ and Fe2+/Fe3+ ratios. The catalyst could maintain good stability even after recycling for five times. Finally, a possible mechanism for phenol hydroxylation via Cu+–OV–Fe2+ and Cu2+–O–Fe3+ redox cycles on CuMgFe–LDHs was proposed.

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“…Accordingly, the calcination temperature is one of the key parameters influencing the structural as well as the surface area of the material. By increasing of calcination temperature until optimum condition will dramatically enhance the surface area of material as studied by Amadine et al 17 . Therefore, the adsorption ability of material will be enhanced as a result of surface area improvement.…”

Section: Bekonang Clay and Andisol Soil Composites Pranoto Pranoto Etmentioning

confidence: 99%

"Application of Bekonang Clay and Andisol Soil Composites as Copper (Ii) Metal Ion Adsorbent in Metal Crafts Wastewater "

2018

RJC

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The utilization of bekonang clay and andisol soil composite as the adsorbent of Cu (II) metal ion has been studied. The aims of this study were to determine the optimum conditions of adsorption including pH of the copper solution, adsorbent calcination temperature, composite composition, adsorbent contact time, and their adsorption capacity in metal craft wastewater. Bekonang clay was activated with 1.5M H2SO4 and andisol soil with 3M NaOH. Experiment of adsorption on Cu(II) metal ion was performed at pH solution of 1, 2, 3, 4, 5, 6, 7, and 8, calcination temperature of 100, 200, 300 and 400 °C, variation of composition bekonang clay and andisol soil composite of 100:0, 25:75, 50:50, 75:25, and 0:100 (w/w) and contact time of 15, 30, 60, and 90 minutes in the batch system. Measurement of final concentration at equilibrium was conducted using AAS. The optimum condition of copper(II) metal ion adsorption was obtained at pH 6, calcination temperature 400 °C, bekonang clay and andisol soil composition 25:75 (w/w), contact time 30 minutes with adsorption capacity by 0.37 mg/g. Adsorption isotherm followed Langmuir and Freundlich isotherm. Adsorbent adsorption capacity in the metal crafts wastewater was 17.38 mg/g.

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Effect of calcination temperature on the structure and catalytic performance of copper–ceria mixed oxide catalysts in phenol hydroxylation

Abstract: We report on highly active CuO@CeO2 catalysts prepared by the surfactant-template method and calcined at different temperatures.

Cited by 76 publications

References 60 publications

CeO₂ and CeO₂:Pr nanocrystalline powders prepared by the polymeric precursor method: Yellow and red pigments with tunable color

CeO₂ and CeO₂:Pr nanocrystalline powders prepared by the polymeric precursor method: Yellow and red pigments with tunable color

Facile Synthesis of CuMgFe Layered Double Hydroxides for Efficient Catalytic Phenol Hydroxylation under Mild Conditions

"Application of Bekonang Clay and Andisol Soil Composites as Copper (Ii) Metal Ion Adsorbent in Metal Crafts Wastewater "

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Effect of calcination temperature on the structure and catalytic performance of copper–ceria mixed oxide catalysts in phenol hydroxylation

Abstract: We report on highly active CuO@CeO2 catalysts prepared by the surfactant-template method and calcined at different temperatures.

Cited by 76 publications

References 60 publications

CeO2 and CeO2:Pr nanocrystalline powders prepared by the polymeric precursor method: Yellow and red pigments with tunable color

CeO2 and CeO2:Pr nanocrystalline powders prepared by the polymeric precursor method: Yellow and red pigments with tunable color

Facile Synthesis of CuMgFe Layered Double Hydroxides for Efficient Catalytic Phenol Hydroxylation under Mild Conditions

"Application of Bekonang Clay and Andisol Soil Composites as Copper (Ii) Metal Ion Adsorbent in Metal Crafts Wastewater "

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CeO₂ and CeO₂:Pr nanocrystalline powders prepared by the polymeric precursor method: Yellow and red pigments with tunable color

CeO₂ and CeO₂:Pr nanocrystalline powders prepared by the polymeric precursor method: Yellow and red pigments with tunable color