A comparative study of partial reduction of ceria via laser ablation in air and soft chemical route

Filotti, L; Bensalem, Abdelhamid; Bozon‐Verduraz, François; Shafeev, G. A.; Voronov, V. V.

doi:10.1016/s0169-4332(96)00665-4

Cited by 23 publications

(15 citation statements)

References 7 publications

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“…Figure compares the Raman spectra obtained under O 2 flow at 173 K after long reduction at 673, 723, and 773 K. The relative intensity of the main band at 467 cm –1 decreased with the reduction temperature and hence the reduction rate because of higher absorption in the visible range . Similarly to after short reduction, a single band of peroxo species was observed at 833 cm –1 after reduction at 673 K. A thin band at 1129 cm –1 arising from superoxo species was also superimposed to the 2LO band at 1189 cm –1 .…”

Section: Resultssupporting

confidence: 91%

Probing reoxidation sites by in situ Raman spectroscopy: differences between reduced CeO₂ and Pt/CeO₂

Daniel¹,

Loridant

2012

J Raman Spectroscopy

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Raman spectroscopy is a powerful technique for detecting peroxo (O2)2– and superoxo (O2)– species adsorbed on defect sites of ceria. These sites are probed by reducing CeO2 at high temperature and then chemisorbing oxygen species at low temperature. In the present study, it is shown for the first time that such Raman characterization has to be achieved at very low laser power to avoid formation of oxygen species by photolysis and analyze only the chemisorbed species. Respecting this requirement, the (O2)2– and (O2)– species formed on 0.7% Pt/CeO2 compound, and the CeO2 support used to prepare it were compared after reduction for various times and at various temperatures. Superoxo species were more stabilized on reduced 0.7% Pt/CeO2 after short reduction at 773 K than on reduced CeO2. Additionally, the distributions of peroxo species adsorbed on defect sites of Pt/CeO2 and CeO2 were significantly different after long reduction at 773 K in spite of similar amounts. Indeed, less stable species were formed during the reduction of 0.7% Pt/CeO2. These two features revealed that new sites were created during the preparation and reduction of Pt/CeO2 compared to its bare support. Copyright © 2012 John Wiley & Sons, Ltd.

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Section: Resultssupporting

confidence: 91%

Probing reoxidation sites by in situ Raman spectroscopy: differences between reduced CeO₂ and Pt/CeO₂

Daniel¹,

Loridant

2012

J Raman Spectroscopy

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“…But, after interaction with the excimer laser beam the surface O 2 content of the PMMA increased markedly. Such a finding is contrary to those of a number of workers [50,51] who have noted that for ceramics, irradiation with an excimer laser beam creates defective energy levels, in particular the formation of O 2 vacancies. Nevertheless, the increase in surface O 2 content of polymer materials after excimer laser interaction is well documented [26][27][28][29][30][31].…”

Section: Discussion Of Laser Effected Wettability Characteristics Modcontrasting

confidence: 88%

Modification of the wettability characteristics of polymethyl methacrylate (PMMA) by means of CO2, Nd:YAG, excimer and high power diode laser radiation

Lawrence

2001

Materials Science and Engineering: A

108

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The surface of the bio-material polymethyl methacrylate (PMMA) was treated with CO 2 , Nd:YAG, excimer and high power diode laser (HPDL) radiation. The laser radiation was found to effect varying degrees of change to the wettability characteristics of the material depending upon the laser used. It was observed that interaction with CO 2 , Nd:YAG and HPDL effected very little change to wettability characteristics of the PMMA. In contrast, interaction of the PMMA with excimer laser radiation resulted an increase in a marked improvement in the wettability characteristics. After excimer laser treatment the surface O 2 content was found to have increased and the material was seen to be more polar in nature. The work has shown that the wettability characteristics of the PMMA could be controlled and/or modified with laser surface treatment. However, a wavelength dependence of the change of the wetting properties could not be deduced from the findings of this work.

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“…Increases in the surface O 2 content were experienced by the mild steel after interaction with CO 2 laser, the Nd:YAG laser and the HPDL beams, whilst interaction of the mild steel with excimer laser radiation resulted in the surface O 2 content of the mild steel decreasing. Such a result is in agreement with the findings of a number of workers [28,29], who have noted that for many materials, irradiation with an excimer laser beam creates defective energy levels, in particular the formation of O 2 vacancies.…”

supporting

confidence: 92%

Wettability characteristics of a modified mild steel with CO₂, Nd:YAG, excimer and high power diode lasers

Lawrence

1999

J. Phys. D: Appl. Phys.

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Interaction of CO 2 , Nd:YAG, excimer and high power diode laser (HPDL) radiation with the surface a common mild steel (EN8) was found to effect changes in the wettability characteristics of the steel, namely changes in the measured contact angle of certain liquids.Such changes were identified as being due to modifications to: (i) the surface roughness,(ii) changes in the surface oxygen content and (iii) changes in the surface energy of the mild steel. However, it was found that changes in the wettability characteristics of the mild steel were predominantly influenced by the surface roughness. To a much lesser extent surface O 2 content is also thought to play a role. The work has shown that the wettability characteristics of the selected mild steel could be controlled and/or modified with laser surface treatment. Moreover, the findings of this work strongly indicate the existence of a relationship between the change of the wetting properties of the mild steel and the laser wavelength.

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A comparative study of partial reduction of ceria via laser ablation in air and soft chemical route

Cited by 23 publications

References 7 publications

Probing reoxidation sites by in situ Raman spectroscopy: differences between reduced CeO₂ and Pt/CeO₂

Probing reoxidation sites by in situ Raman spectroscopy: differences between reduced CeO₂ and Pt/CeO₂

Modification of the wettability characteristics of polymethyl methacrylate (PMMA) by means of CO2, Nd:YAG, excimer and high power diode laser radiation

Wettability characteristics of a modified mild steel with CO₂, Nd:YAG, excimer and high power diode lasers

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A comparative study of partial reduction of ceria via laser ablation in air and soft chemical route

Cited by 23 publications

References 7 publications

Probing reoxidation sites by in situ Raman spectroscopy: differences between reduced CeO2 and Pt/CeO2

Probing reoxidation sites by in situ Raman spectroscopy: differences between reduced CeO2 and Pt/CeO2

Modification of the wettability characteristics of polymethyl methacrylate (PMMA) by means of CO2, Nd:YAG, excimer and high power diode laser radiation

Wettability characteristics of a modified mild steel with CO2, Nd:YAG, excimer and high power diode lasers

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Product

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About

Probing reoxidation sites by in situ Raman spectroscopy: differences between reduced CeO₂ and Pt/CeO₂

Probing reoxidation sites by in situ Raman spectroscopy: differences between reduced CeO₂ and Pt/CeO₂

Wettability characteristics of a modified mild steel with CO₂, Nd:YAG, excimer and high power diode lasers