Photo-EPR Studies of KTN-1.2: Evidences of the Nb<sup>4+</sup>−O<sup>−</sup>Polaronic Excitons

Yusupov, R. V.; Gracheva, I. N.; Родионов, А. А.; Сырников, П. П.; Gubaev, A. I.; Dejneka, A.; Jastrabı́k, L.; Трепаков, В. А.; Салахов, М. Х.

doi:10.1080/00150193.2012.677672

Cited by 2 publications

(1 citation statement)

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“…Considering the fact that there are unpaired electrons in both Nb 4+ and V O , the samples were further measured by electron paramagnetic resonance (EPR) to determine the presence of unpaired electrons. Black r-Nb 2 O 5 shows strong EPR signals at g = 1.989 and g = 2.031, which are assigned to Nb 4+ , [39][40][41] whereas no signal is observed in the Nb 2 O 5 , as shown in Fig. S2.…”

Section: Dalton Transactions Papermentioning

confidence: 99%

Black Nb₂O₅ nanorods with improved solar absorption and enhanced photocatalytic activity

et al. 2016

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Black titania, with greatly improved solar absorption, has demonstrated its effectiveness in photocatalysis and photoelectrochemical cells (PEC), inspiring us to explore the blackening of other wide band-gap oxide materials for enhanced performance. Herein, we report the fabrication of black, reduced Nb2O5 nanorods (r-Nb2O5), with active exposed (001) surfaces, and their enhanced photocatalytic and PEC properties. Black r-Nb2O5 nanorods were obtained via reduction of pristine Nb2O5 by molten aluminum in a two-zone furnace. Unlike the black titania, r-Nb2O5 nanorods are well-crystallized, without a core-shell structure, which makes them outstanding in photocatalytic stability. Substantial Nb(4+) cation and oxygen vacancies (VO) were introduced into r-Nb2O5, resulting in the enhanced absorption in both the visible and near-infrared regions and improved charge separation and transport capability. The advantage of the r-Nb2O5 was also proved by its more efficient photoelectrochemical performance (138 times at 1.23 VRHE) and higher photocatalytic hydrogen-generation activity (13 times) than pristine Nb2O5. These results indicate that black r-Nb2O5 is a promising material for PEC application and photocatalysis.

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Section: Dalton Transactions Papermentioning

confidence: 99%

Black Nb₂O₅ nanorods with improved solar absorption and enhanced photocatalytic activity

et al. 2016

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New Solids in As-O-Mo, As(P)-O-Mo(W) and As(P)-O-Nb(W) Systems That Exhibit Nonlinear Optical Properties

et al. 2021

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Interactions between well-mixed fine powders of As2O3, P2O5, MoO3, WO3 and Nb2O5 at different stoichiometry in quartz ampoules under vacuum at ~1000 °C in the presence of metallic molybdenum (or niobium), over several weeks, led to shiny dichroic crystalline materials being formed in cooler parts of the reaction vessel. An addition of small quantities of metals-Mo or Nb-was made with the aim of partially reducing their highly oxidized Mo(VI), W(VI) or Nb(V) species to corresponding Mo(V), W(V) and Nb(IV) centers, in order to form mixed valence solids. Sublimed crystals of four new compounds were investigated using a variety of techniques, with prime emphasis on the X-ray analysis, followed by spectroscopy (diffusion reflectance, IR, Raman and EPR), second harmonic generation (SHG), thermal analysis under N2 and air atmosphere, and single crystals electrical conductivity studies. The results evidenced the formation of new complex solids of previously unknown compositions and structures. Three out of four compounds crystallized in non-centrosymmetric space groups and represent layered 2D polymeric puckered structures that being stacked on each other form 3D lattices. All new solids exhibit strong second-harmonic-generation (SHG effect; based on YAG 1064 nm tests with detection of 532 nm photons), and a rare photosalient effect when crystals physically move in the laser beam. Single crystals’ electrical conductivity of the four new synthesized compounds was measured, and the results showed their semiconductor behavior. Values of band gaps of these new solids were determined using diffusion reflectance spectroscopy in the visible region. Aspects of new solids’ practical usefulness are discussed.

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Photo-EPR Studies of KTN-1.2: Evidences of the Nb⁴⁺−O⁻Polaronic Excitons

Cited by 2 publications

References 20 publications

Black Nb₂O₅ nanorods with improved solar absorption and enhanced photocatalytic activity

Black Nb₂O₅ nanorods with improved solar absorption and enhanced photocatalytic activity

New Solids in As-O-Mo, As(P)-O-Mo(W) and As(P)-O-Nb(W) Systems That Exhibit Nonlinear Optical Properties

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Photo-EPR Studies of KTN-1.2: Evidences of the Nb4+−O−Polaronic Excitons

Cited by 2 publications

References 20 publications

Black Nb2O5 nanorods with improved solar absorption and enhanced photocatalytic activity

Black Nb2O5 nanorods with improved solar absorption and enhanced photocatalytic activity

New Solids in As-O-Mo, As(P)-O-Mo(W) and As(P)-O-Nb(W) Systems That Exhibit Nonlinear Optical Properties

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Product

Resources

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Photo-EPR Studies of KTN-1.2: Evidences of the Nb⁴⁺−O⁻Polaronic Excitons

Black Nb₂O₅ nanorods with improved solar absorption and enhanced photocatalytic activity

Black Nb₂O₅ nanorods with improved solar absorption and enhanced photocatalytic activity