Raman, photoluminescence and EPR spectroscopic characterization of europium(III) oxide–lead dioxide–tellurite glassy network

Dehelean, Adriana; Rada, S.; Popa, Adriana; Suciu, Ramona-Crina; Culea, E.

doi:10.1016/j.jlumin.2016.04.027

Cited by 13 publications

(4 citation statements)

References 35 publications

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“…5b ). These two EPR signals are attributed to paramagnetic Eu 2+ species, because the Eu 3+ ions have no EPR signals, while the Eu 2+ ions are EPR active 41 , 42 . The valence change of the Eu 2 oxo-clusters can be attributed to the photo-induced LMCT process.…”

Section: Resultsmentioning

confidence: 99%

Photo-generated dinuclear {Eu(II)}2 active sites for selective CO2 reduction in a photosensitizing metal-organic framework

et al. 2018

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Photocatalytic reduction of CO2 is a promising approach to achieve solar-to-chemical energy conversion. However, traditional catalysts usually suffer from low efficiency, poor stability, and selectivity. Here we demonstrate that a large porous and stable metal-organic framework featuring dinuclear Eu(III)2 clusters as connecting nodes and Ru(phen)3-derived ligands as linkers is constructed to catalyze visible-light-driven CO2 reduction. Photo-excitation of the metalloligands initiates electron injection into the nodes to generate dinuclear {Eu(II)}2 active sites, which can selectively reduce CO2 to formate in a two-electron process with a remarkable rate of 321.9 μmol h−1 mmolMOF−1. The electron transfer from Ru metalloligands to Eu(III)2 catalytic centers are studied via transient absorption and theoretical calculations, shedding light on the photocatalytic mechanism. This work highlights opportunities in photo-generation of highly active lanthanide clusters stabilized in MOFs, which not only enables efficient photocatalysis but also facilitates mechanistic investigation of photo-driven charge separation processes.

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Section: Resultsmentioning

confidence: 99%

Photo-generated dinuclear {Eu(II)}2 active sites for selective CO2 reduction in a photosensitizing metal-organic framework

et al. 2018

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“…On the other hand, the g ∼ 4.30 line observed at a lower field (∼100 mT) cannot be assigned to electron or hole trap centers in the host matrix; thus, it is a characteristic resonance signal originating from divalent Eu ions. 37,38 The decrease in the intensity of the resonance signal at g ∼ 2.20 on co-doping can be attributed to a decrease in the concentration of electron trap centers in the host matrix on Eu 3+ reduction.…”

Section: Resultsmentioning

confidence: 99%

“…Paper PCCP in the host matrix; thus, it is a characteristic resonance signal originating from divalent Eu ions. 37,38 The decrease in the intensity of the resonance signal at g B 2.20 on co-doping can be attributed to a decrease in the concentration of electron trap centers in the host matrix on Eu 3+ reduction. The evolution of this signal only in the co-doped LTB samples indicates the formation of paramagnetic Eu 2+ ions due to the interactions between actinide and lanthanide ions, U 6+ and Eu 3+ , respectively.…”

Section: Spectroscopic Insight To Probe the Role Of U 6+ In The Stabi...mentioning

confidence: 99%

Stabilization of Eu²⁺ in Li₂B₄O₇ with the BO₃ network through U⁶⁺ co-doping and defect engineering

Balhara

Gupta

Patra

et al. 2023

Phys. Chem. Chem. Phys.

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“…The samples were characterized by several methods: XRD, SEM analysis, FTIR, UV-Vis, PL, Raman and XAS spectroscopy that were previously described by Rada et al (2013Rada et al ( , 2017Rada et al ( , 2019, Rada, Zhang et al (2018) and Dehelean et al (2016).…”

Section: Experimental Datamentioning

confidence: 99%

Characteristics and local structure of hafnia-silicate-zirconate ceramic nanomixtures

Pop

Rada

et al. 2020

J Synchrotron Radiat

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Zirconate systems having the composition 3HfO2·15SiO2·xY2O3·(82 − x)ZrO2, where x = 2, 7 and 12 mol% Y2O3, were synthesized by a sol-gel method. The analysis of X-ray diffraction data showed the presence of the t-ZrO2, m-ZrO2, m-HfO2, Y2SiO5 and Y2Si2O7 crystalline phases in a ceramic nanomixture. Spectroscopic data show that the increase of the Y2O3 content of samples determines the increase of the t-ZrO2, m-HfO2 and silicate crystalline phases. Gap energy values decrease almost linearly with increasing Y2O3 content of samples. A detailed study of XANES data does not show a significant difference with increasing Y2O3 content of the samples suggesting an appreciable stability of the hafnium ions +4 oxidation state and their microvicinity. EXAFS results show that the local structure around the Hf cation is similar to that from the monoclinic crystalline HfO2 where the Hf–O coordination number tends to 7. The bond lengths of Hf–O shells show small deviations from ∼2.12 Å and the Hf–metal paths become more structured by increasing the Y2O3 content of the samples.

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Raman, photoluminescence and EPR spectroscopic characterization of europium(III) oxide–lead dioxide–tellurite glassy network

Cited by 13 publications

References 35 publications

Photo-generated dinuclear {Eu(II)}2 active sites for selective CO2 reduction in a photosensitizing metal-organic framework

Photo-generated dinuclear {Eu(II)}2 active sites for selective CO2 reduction in a photosensitizing metal-organic framework

Stabilization of Eu²⁺ in Li₂B₄O₇ with the BO₃ network through U⁶⁺ co-doping and defect engineering

Characteristics and local structure of hafnia-silicate-zirconate ceramic nanomixtures

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Raman, photoluminescence and EPR spectroscopic characterization of europium(III) oxide–lead dioxide–tellurite glassy network

Cited by 13 publications

References 35 publications

Photo-generated dinuclear {Eu(II)}2 active sites for selective CO2 reduction in a photosensitizing metal-organic framework

Photo-generated dinuclear {Eu(II)}2 active sites for selective CO2 reduction in a photosensitizing metal-organic framework

Stabilization of Eu2+ in Li2B4O7 with the BO3 network through U6+ co-doping and defect engineering

Characteristics and local structure of hafnia-silicate-zirconate ceramic nanomixtures

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Stabilization of Eu²⁺ in Li₂B₄O₇ with the BO₃ network through U⁶⁺ co-doping and defect engineering