Studies of the local distortions for n d 1 (Mo 5+ and W 5+ ) impurities in KTP crystals

Ding, Chang‐Chun; Wu, Shao-Yi; Zhang, Lijuan; Hu, Xian-Fen; Li, Guoliang

doi:10.1016/j.poly.2015.12.013

Cited by 7 publications

(4 citation statements)

References 40 publications

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“…At a low temperature (5 K), additional weak orthorhombic signals are detected at higher magnetic fields (350–420 mT region). These last EPR signals characterized by g-values close to 1.7 may be due to W 5+ (d 1 ) ions in distorted environments, most likely located close to the crystallite surface [35,36]. For the raw (blue) sample, the axial EPR signal with g ⊥ = 1.76 and g // = 1.71 is observed at low temperature (5 K) and can unambiguously be associated with W 5+ ions in a more regular site (most likely with C 4v symmetry) within the WO 3 structure [37,38,39].…”

Section: Resultsmentioning

confidence: 99%

Nanoparticles (NPs) of WO3-x Compounds by Polyol Route with Enhanced Photochromic Properties

et al. 2019

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Tungsten trioxide (WO3) is well-known as one of the most promising chromogenic compounds. It has a drastic change of coloration induced from different external stimuli and so its applications are developed as gas sensors, electrochromic panels or photochromic sensors. This paper focuses on the photochromic properties of nanoWO3, with tunable composition (with tunable oxygen sub-stoichiometry). Three reference samples with yellow, blue and black colors were prepared from polyol synthesis followed by post annealing under air, none post-annealing treatment, or a post-annealing under argon atmosphere. These three samples differ in terms of crystallographic structure (cubic system versus monoclinic system), oxygen vacancy concentration, electronic band diagram with occurrence of free or trapped electrons and their photochromic behavior. Constituting one main finding, it is shown that the photochromic behavior is highly dependent on the compound’s composition/color. Rapid and important change of coloration under UV (ultraviolet) irradiation was evidenced especially on the blue compound, i.e., the photochromic coloring efficiency of this compound in terms of contrast between bleached and colored phase, as the kinetic aspect is high. The photochromism is reversible in a few hours. This hence opens a new window for the use of tungsten oxide as smart photochromic compounds.

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Section: Resultsmentioning

confidence: 99%

Nanoparticles (NPs) of WO3-x Compounds by Polyol Route with Enhanced Photochromic Properties

et al. 2019

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“…In all cases, a peak with a g value of 2.043 was assigned to the oxygen vacancy with the unpaired single electron in the lattice structure of ZrO 2 support . Noticeably, Ru-2.7 and Ru-4.7 samples presented two new signals with g values of 1.935 and 1.896, respectively, which are attributed to g ⊥ and g ∥ bands of Mo 5+ species with the 4d 1 unpaired electron. − The appearance of Mo 5+ species confirmed the formation of oxygen defects related to the surface MoO x component. Correspondingly, the number of oxygen vacancies with unpaired electrons could be quantified by the spin counts obtained from the EPR spectra.…”

Section: Resultsmentioning

confidence: 75%

MoO_x-Decorated ZrO₂ Nanostructures Supporting Ru Nanoclusters for Selective Hydrodeoxygenation of Anisole to Benzene

Liang

Liu²,

Fan

et al. 2021

ACS Appl. Nano Mater.

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Currently, the hydrodeoxygenation (HDO) process of biomass-derived phenolics is regarded as one of the most promising methods of upgrading to produce various high-value-added chemical raw feeds (e.g., benzene, toluene, and xylene) as well as potentially applied bio-oils with less oxygen content. In this work, a series of surface MoO 3decorated nanosized tetragonal zirconia (t-ZrO 2 ) supports were utilized to immobilize Ru nanoclusters for the aqueous-phase HDO of anisole. Structural characterizations revealed the presence of uniformly dispersed Ru nanoclusters and defective MoO x clusters on the t-ZrO 2 , thereby forming strong Ru-MoO x interactions and thus the generation of abundant interfacial Ru δ+ species and oxygen vacancies. As-fabricated supported Ru nanoclusters as the catalyst could achieve a much higher benzene selectivity of ∼84.7% than the Mo-free supported Ru one (25.1%) in the HDO of anisole under mild reaction conditions, despite a lowered anisole conversion, which was associated with the cooperative effect between active Ru 0 nanoclusters and favorable interfacial Ru δ+ -O v -Mo 5+ sites (O v = oxygen vacancy), thereby enhancing the adsorption of the methoxy group in anisole and the further demethoxylation to form benzene. Our present findings provide a promising way to regulate the selectivity of deoxygenated products in the HDO of biomass-derived phenolics via finely tuning active metal−support interfacial sites.

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“…Firstly, only the contributions from the nearest neighbor oxygen ligands of the metallic W 5+ ion are considered from the cluster approach. Fortunately, the approach has been proved to be valid by many theoretical works on EPR parameters [8,9,28,29,[32][33][34][38][39][40].…”

Section: Discussionmentioning

confidence: 99%

“…A denotes the integral R ns |∂/∂y| np y with the impurity-ligand distance R of the studied system. More information can be found in the literatures [28,35,37,38].…”

Section: Perturbation Formulae Of G-factorsmentioning

confidence: 99%

Theoretical studies on the g-factors and the local structure of W5+ ions in tungsten phosphate glasses

et al. 2023

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In this work, we adopt the three-order perturbation formulae for g-factors (g//, g^) of d1 ions in the octahedral environment to calculate the g-factors of W5+ ions in tungsten phosphate glasses containing lithium (P2O5-Li2WO4-Li2O). In the light of the high valence state of the studied W5+ centers and hence the strong covalency of the studied octahedral [WO6]7- cluster, we consider the contributions to g-factors from the ligand orbital and spin-orbit (SO) coupling interactions based on the cluster approach. The required tetragonal crystal-field parameters are calculated from the local structure of W5+ ions based on the superposition model. According to the theoretical calculations, we find that the octahedral [WO6]7- clusters possess the tetragonally compressed distortion with a shorter W-O bond length (≈1.54 Å) and a longer one (≈2.26 Å) along C4 axis and four normal W-O bond length (≈1.94 Å) in the perpendicular plane, which infers that the W5+ ions are in the form of tungstyl ions (i.e., WO3-). Based on the local structural data, the theoretical values of g// and g^ agree well with the experimental values.

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Studies of the local distortions for n d 1 (Mo 5+ and W 5+ ) impurities in KTP crystals

Cited by 7 publications

References 40 publications

Nanoparticles (NPs) of WO3-x Compounds by Polyol Route with Enhanced Photochromic Properties

Nanoparticles (NPs) of WO3-x Compounds by Polyol Route with Enhanced Photochromic Properties

MoO_x-Decorated ZrO₂ Nanostructures Supporting Ru Nanoclusters for Selective Hydrodeoxygenation of Anisole to Benzene

Theoretical studies on the g-factors and the local structure of W5+ ions in tungsten phosphate glasses

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Studies of the local distortions for n d 1 (Mo 5+ and W 5+ ) impurities in KTP crystals

Cited by 7 publications

References 40 publications

Nanoparticles (NPs) of WO3-x Compounds by Polyol Route with Enhanced Photochromic Properties

Nanoparticles (NPs) of WO3-x Compounds by Polyol Route with Enhanced Photochromic Properties

MoOx-Decorated ZrO2 Nanostructures Supporting Ru Nanoclusters for Selective Hydrodeoxygenation of Anisole to Benzene

Theoretical studies on the g-factors and the local structure of W5+ ions in tungsten phosphate glasses

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MoO_x-Decorated ZrO₂ Nanostructures Supporting Ru Nanoclusters for Selective Hydrodeoxygenation of Anisole to Benzene