Inna Baklanova - Academia.edu (original) (raw)
Papers by Inna Baklanova
Russian Journal of Physical Chemistry A, 2009
Hydrated alkaline-earth metal tungstates Ba4Ca2 + x W2 - x O12 - 2 x with perovskite structure we... more Hydrated alkaline-earth metal tungstates Ba4Ca2 + x W2 - x O12 - 2 x with perovskite structure were studied by the thermogravimetry, 1H NMR, IR, and Raman spectroscopy methods. Electrical conductivity and transfer numbers were measured with varying T, p_{O_2 } and p_{H_2 O} . The solid solutions are capable of reversibly intercalating water and can exhibit high-temperature proton transport.
Physics of the Solid State, 2019
Nanophosphors in the amorphous state are first obtained via pulsed electron beam evaporation of t... more Nanophosphors in the amorphous state are first obtained via pulsed electron beam evaporation of targets made of polycrystalline phosphors with the compositions Ca 2 M 8 (SiO 4) 6 O 2 :Eu (M = Y and Gd) and Ca 2 La 8 (GeO 4) 6 O 2 :Eu with the structure of oxyapatite. Reduction of ions Eu 3+ → Eu 2+ in the electron beam is found. Modification of the Raman scattering (RS) spectra of the samples in the case of a decrease in the size of the particles from bulk to a nanosized state is found. The change in the forbidden band width E g of the samples in the case of transition from a bulk powder to an NP is considered. The spectral and luminescence characteristics of the samples in the polycrystalline and nanoamorphous states are studied. It is shown that, in the case of transition to nanosamples, the ligand field around Eu 2+ changes. This may be due to the violation of the translational symmetry in the NP. The bond between the 4f and 5d electrons weakens. Degeneracy of the 2 e g level appears. Presumably, the reduction of ions Eu 3+ → Eu 2+ in the electron beam due to the breaking of the Si(Ge)-O bond in the process of evaporation of the samples and capture of the released electron by the Eu 3+ ions is found.
Materials Research Express, 2019
Theoretical and Experimental Chemistry, 2011
The temperature and concentration dependence of the phase transformation of anatase to rutile in ... more The temperature and concentration dependence of the phase transformation of anatase to rutile in Ti 1-x M x O 2-x/2 was investigated by Raman spectroscopy. It was shown that the anatase phase is stabilized most effectively by the Eu 3+ dopant.
Theoretical and Experimental Chemistry, 2013
ABSTRACT Europium-doped zinc formate was synthesized by crystallization from a solution prepared ... more ABSTRACT Europium-doped zinc formate was synthesized by crystallization from a solution prepared by the reaction of the diluted formic acid on a mixture of ZnO and Eu2O3, Zn1–x Eux (HCOO)2+x 2H2O (0.005 ≤ x ≤ 0.05) under heating. Thermolysis of Zn1–x Eux (HCOO)2+x 2H2O gave Zn1–x Eux O1+x with no more than 2.5 at.% degree of replacement of zinc by europium. The influence of Eu3+ on the luminescent properties of the samples synthesized was studied by optical spectroscopy (IR, Raman, and UV visible and emission spectra).
Glass Physics and Chemistry, 2003
Bulletin of the Russian Academy of Sciences: Physics, 2008
The synthesis conditions for single-phase solid solutions based on lanthanum gallate, LaGa 1x Mg ... more The synthesis conditions for single-phase solid solutions based on lanthanum gallate, LaGa 1x Mg x O 3-δ (x = 0-0.25, solid-phase method) and La 1y Sr y Ga 1y Mg y O 3-δ (y = 0-0.2, glycine nitrate method), have been investigated. The structural parameters have been calculated using X-ray powder diffraction data. The IR and Raman spectra have been analyzed. Regularities in the changes in the structural parameters and vibrational spectra with composition are established.
Russian Journal of Inorganic Chemistry, 2010
ABSTRACT
Russian Journal of Inorganic Chemistry, 2011
ABSTRACT Potassium oxosulfatovanadate(V) K3VO2(SO4)2 has been obtained by solid-phase synthesis f... more ABSTRACT Potassium oxosulfatovanadate(V) K3VO2(SO4)2 has been obtained by solid-phase synthesis from K2SO4, K2S2O7, and V2O5 (2: 1: 1), and its formation conditions, crystal structure, and physiochemical properties have been studied. The conversions of K3VO2(SO4)2 in contact with potassium vanadates and other potassium oxosulfatovanadates(V) are considered in terms of phase relations in the K2O-V2O5-SO3 system, which models the active component of vanadium catalysts for sulfur dioxide oxidation into sulfur trioxide. The X-ray diffraction pattern of K3VO2(SO4)2 is indexed in the monoclinic system (space group P21) with unit cell parameters of a = 10.0408(1) Å, b = 7.2312(1) Å, c = 7.3821(1) Å, β = 104.457(1)°, Z = 2, and V = 519.02 Å3. The crystal structure of K3VO2(SO4)2 is built from [VO2(SO4)2]3− complex anions, in which the vanadium atom is in an octahedral oxygen environment formed by two terminal oxygen atoms (V-O(6) = 1.605(7) Å, V-O(10) = 1.619(7) Å and four oxygen atoms of the two chelating sulfate anions. The vibrational spectra of K3VO2(SO4)2 are analyzed using these structural data.
Physics of the Solid State, 2013
ABSTRACT The precursor-derived nanostructured solid solutions Zn0.95 M 0.05O ( M = Co, Ni, Cu) wi... more ABSTRACT The precursor-derived nanostructured solid solutions Zn0.95 M 0.05O ( M = Co, Ni, Cu) with tubular aggregates have been investigated using optical absorption spectroscopy and electron paramagnetic resonance. The dependences of the concentration of intrinsic defects V {o/+} and the effective band gap on the dopant type have been determined. It has been shown using the oxidation reaction of hydroquinone dissolved in water as an example that an increase in the photocatalytic activity in the series ZnO → Zn0.95Ni0.05O → Zn0.95Co0.05O Zn0.95Cu0.05O in the ultraviolet and visible spectral regions correlates with a decrease in the band gap and with an increase in the concentration of oxygen vacancies V {O/+}.
Physics of the Solid State, 2013
We have investigated the electronic structure and optical properties of CdSe doped with molecular... more We have investigated the electronic structure and optical properties of CdSe doped with molecular oxygen by using first-principle local density-functional theory (DFT) based on a hybrid functional. We find that interstitial oxygen molecule introduces two kinds of states in CdSe: filled states which are degenerate and strongly hybridized with the top of the valence bands and one empty state lying in the middle of the gap. The origin of these states can be traced to the 1π g molecular orbitals of O 2. We compared the optical absorption spectra of CdSe with and without molecular oxygen. States introduced by the oxygen molecules lower the absorption onset of CdSe to ~1.0eV while hybridization causes redistribution of the oscillator strengths of CdSe transitions from the ultraviolet to the infrared. Our results demonstrate that doping small molecules into semiconductors can alter the electronic and optical properties of the host in ways different from atomic dopants.
Chemical Physics Letters, 2010
ABSTRACT We report on a Raman scattering study of the LiCoO2, γ-Na0.7CoO2 and Li0.42Na0.36CoO2 ph... more ABSTRACT We report on a Raman scattering study of the LiCoO2, γ-Na0.7CoO2 and Li0.42Na0.36CoO2 phases. The Raman spectrum of the ordered cobaltite Li0.42Na0.36CoO2 consists of a set of seven distinct peaks with the wave numbers around 190, 445, 467, 513, 572, 609 and 674cm−1. It exhibits features of the spectra for LiCoO2 and γ-Na0.7CoO2 and therefore can be considered as a superposition of these two spectra. It may be supposed that in the structure of the double cobaltite the bonding between sodium- and lithium-containing blocks is rather weak.
Journal of Alloys and Compounds, 2013
For titanium dioxide with anatase structure doped with carbon or nitrogen, the first-principle me... more For titanium dioxide with anatase structure doped with carbon or nitrogen, the first-principle method of projector augmented waves (PAW) is used to calculate electronic band structure, to evaluate vacancy formation energy for the oxygen sublattice, and to analyze optical absorption. It is demonstrated that the presence of carbon dopants results in the stabilization of oxygen vacancies and leads to increased absorption in the visible spectrum, which can facilitate the photocatalytic activity. The presence of nitrogen dopant also facilitates vacancy stabilization but no increase in the interband absorption is expected in the visible spectrum, i.e., the presence of nitrogen dopant cannot be considered as a factor contributing to increased photocatalytic activity. It follows from the calculated data that the maximum photocatalytic activity should be expected for the partiallyreduced anatase doped with carbon because of the absorption in the visible spectrum that combines with long time of electron-hole recombination.
Nanosystems: Physics, Chemistry, Mathematics, 2020
Using the thermodynamic and kinetic approaches, it was found that Cu(NH 3) 2+ 4 aq complex predom... more Using the thermodynamic and kinetic approaches, it was found that Cu(NH 3) 2+ 4 aq complex predominating at 23 • C spontaneously decomposes at elevated temperatures, forming CuO precipitate in a bulk solution and a layer (CuO||SiO 2) on the surface of silica glass. The rates of these heterogeneous processes are fairly well described by the 1st-order reaction of decay of the Cu(NH 3) 2+ 4 aq complex. The formation of the CuO precipitate and layer is a two-step kinetic process. The rate of precipitate formation dominates above 65 • C while the rate of the layer formation prevails below this value. The CuO||SiO 2 material synthesized below 65 • possesses an optical bandgap of (1.25±0.05) eV, which is smaller compared to the crystals of commercial CuO. The CuO||SiO 2 material displays a photocatalytic activity in the reaction of UV-decomposition of benzoquinone-hydroquinone. It was discovered that the photocatalytic activity depends on the thickness of the photocatalyst layer.
Russian Journal of Physical Chemistry A, 2009
Hydrated alkaline-earth metal tungstates Ba4Ca2 + x W2 - x O12 - 2 x with perovskite structure we... more Hydrated alkaline-earth metal tungstates Ba4Ca2 + x W2 - x O12 - 2 x with perovskite structure were studied by the thermogravimetry, 1H NMR, IR, and Raman spectroscopy methods. Electrical conductivity and transfer numbers were measured with varying T, p_{O_2 } and p_{H_2 O} . The solid solutions are capable of reversibly intercalating water and can exhibit high-temperature proton transport.
Physics of the Solid State, 2019
Nanophosphors in the amorphous state are first obtained via pulsed electron beam evaporation of t... more Nanophosphors in the amorphous state are first obtained via pulsed electron beam evaporation of targets made of polycrystalline phosphors with the compositions Ca 2 M 8 (SiO 4) 6 O 2 :Eu (M = Y and Gd) and Ca 2 La 8 (GeO 4) 6 O 2 :Eu with the structure of oxyapatite. Reduction of ions Eu 3+ → Eu 2+ in the electron beam is found. Modification of the Raman scattering (RS) spectra of the samples in the case of a decrease in the size of the particles from bulk to a nanosized state is found. The change in the forbidden band width E g of the samples in the case of transition from a bulk powder to an NP is considered. The spectral and luminescence characteristics of the samples in the polycrystalline and nanoamorphous states are studied. It is shown that, in the case of transition to nanosamples, the ligand field around Eu 2+ changes. This may be due to the violation of the translational symmetry in the NP. The bond between the 4f and 5d electrons weakens. Degeneracy of the 2 e g level appears. Presumably, the reduction of ions Eu 3+ → Eu 2+ in the electron beam due to the breaking of the Si(Ge)-O bond in the process of evaporation of the samples and capture of the released electron by the Eu 3+ ions is found.
Materials Research Express, 2019
Theoretical and Experimental Chemistry, 2011
The temperature and concentration dependence of the phase transformation of anatase to rutile in ... more The temperature and concentration dependence of the phase transformation of anatase to rutile in Ti 1-x M x O 2-x/2 was investigated by Raman spectroscopy. It was shown that the anatase phase is stabilized most effectively by the Eu 3+ dopant.
Theoretical and Experimental Chemistry, 2013
ABSTRACT Europium-doped zinc formate was synthesized by crystallization from a solution prepared ... more ABSTRACT Europium-doped zinc formate was synthesized by crystallization from a solution prepared by the reaction of the diluted formic acid on a mixture of ZnO and Eu2O3, Zn1–x Eux (HCOO)2+x 2H2O (0.005 ≤ x ≤ 0.05) under heating. Thermolysis of Zn1–x Eux (HCOO)2+x 2H2O gave Zn1–x Eux O1+x with no more than 2.5 at.% degree of replacement of zinc by europium. The influence of Eu3+ on the luminescent properties of the samples synthesized was studied by optical spectroscopy (IR, Raman, and UV visible and emission spectra).
Glass Physics and Chemistry, 2003
Bulletin of the Russian Academy of Sciences: Physics, 2008
The synthesis conditions for single-phase solid solutions based on lanthanum gallate, LaGa 1x Mg ... more The synthesis conditions for single-phase solid solutions based on lanthanum gallate, LaGa 1x Mg x O 3-δ (x = 0-0.25, solid-phase method) and La 1y Sr y Ga 1y Mg y O 3-δ (y = 0-0.2, glycine nitrate method), have been investigated. The structural parameters have been calculated using X-ray powder diffraction data. The IR and Raman spectra have been analyzed. Regularities in the changes in the structural parameters and vibrational spectra with composition are established.
Russian Journal of Inorganic Chemistry, 2010
ABSTRACT
Russian Journal of Inorganic Chemistry, 2011
ABSTRACT Potassium oxosulfatovanadate(V) K3VO2(SO4)2 has been obtained by solid-phase synthesis f... more ABSTRACT Potassium oxosulfatovanadate(V) K3VO2(SO4)2 has been obtained by solid-phase synthesis from K2SO4, K2S2O7, and V2O5 (2: 1: 1), and its formation conditions, crystal structure, and physiochemical properties have been studied. The conversions of K3VO2(SO4)2 in contact with potassium vanadates and other potassium oxosulfatovanadates(V) are considered in terms of phase relations in the K2O-V2O5-SO3 system, which models the active component of vanadium catalysts for sulfur dioxide oxidation into sulfur trioxide. The X-ray diffraction pattern of K3VO2(SO4)2 is indexed in the monoclinic system (space group P21) with unit cell parameters of a = 10.0408(1) Å, b = 7.2312(1) Å, c = 7.3821(1) Å, β = 104.457(1)°, Z = 2, and V = 519.02 Å3. The crystal structure of K3VO2(SO4)2 is built from [VO2(SO4)2]3− complex anions, in which the vanadium atom is in an octahedral oxygen environment formed by two terminal oxygen atoms (V-O(6) = 1.605(7) Å, V-O(10) = 1.619(7) Å and four oxygen atoms of the two chelating sulfate anions. The vibrational spectra of K3VO2(SO4)2 are analyzed using these structural data.
Physics of the Solid State, 2013
ABSTRACT The precursor-derived nanostructured solid solutions Zn0.95 M 0.05O ( M = Co, Ni, Cu) wi... more ABSTRACT The precursor-derived nanostructured solid solutions Zn0.95 M 0.05O ( M = Co, Ni, Cu) with tubular aggregates have been investigated using optical absorption spectroscopy and electron paramagnetic resonance. The dependences of the concentration of intrinsic defects V {o/+} and the effective band gap on the dopant type have been determined. It has been shown using the oxidation reaction of hydroquinone dissolved in water as an example that an increase in the photocatalytic activity in the series ZnO → Zn0.95Ni0.05O → Zn0.95Co0.05O Zn0.95Cu0.05O in the ultraviolet and visible spectral regions correlates with a decrease in the band gap and with an increase in the concentration of oxygen vacancies V {O/+}.
Physics of the Solid State, 2013
We have investigated the electronic structure and optical properties of CdSe doped with molecular... more We have investigated the electronic structure and optical properties of CdSe doped with molecular oxygen by using first-principle local density-functional theory (DFT) based on a hybrid functional. We find that interstitial oxygen molecule introduces two kinds of states in CdSe: filled states which are degenerate and strongly hybridized with the top of the valence bands and one empty state lying in the middle of the gap. The origin of these states can be traced to the 1π g molecular orbitals of O 2. We compared the optical absorption spectra of CdSe with and without molecular oxygen. States introduced by the oxygen molecules lower the absorption onset of CdSe to ~1.0eV while hybridization causes redistribution of the oscillator strengths of CdSe transitions from the ultraviolet to the infrared. Our results demonstrate that doping small molecules into semiconductors can alter the electronic and optical properties of the host in ways different from atomic dopants.
Chemical Physics Letters, 2010
ABSTRACT We report on a Raman scattering study of the LiCoO2, γ-Na0.7CoO2 and Li0.42Na0.36CoO2 ph... more ABSTRACT We report on a Raman scattering study of the LiCoO2, γ-Na0.7CoO2 and Li0.42Na0.36CoO2 phases. The Raman spectrum of the ordered cobaltite Li0.42Na0.36CoO2 consists of a set of seven distinct peaks with the wave numbers around 190, 445, 467, 513, 572, 609 and 674cm−1. It exhibits features of the spectra for LiCoO2 and γ-Na0.7CoO2 and therefore can be considered as a superposition of these two spectra. It may be supposed that in the structure of the double cobaltite the bonding between sodium- and lithium-containing blocks is rather weak.
Journal of Alloys and Compounds, 2013
For titanium dioxide with anatase structure doped with carbon or nitrogen, the first-principle me... more For titanium dioxide with anatase structure doped with carbon or nitrogen, the first-principle method of projector augmented waves (PAW) is used to calculate electronic band structure, to evaluate vacancy formation energy for the oxygen sublattice, and to analyze optical absorption. It is demonstrated that the presence of carbon dopants results in the stabilization of oxygen vacancies and leads to increased absorption in the visible spectrum, which can facilitate the photocatalytic activity. The presence of nitrogen dopant also facilitates vacancy stabilization but no increase in the interband absorption is expected in the visible spectrum, i.e., the presence of nitrogen dopant cannot be considered as a factor contributing to increased photocatalytic activity. It follows from the calculated data that the maximum photocatalytic activity should be expected for the partiallyreduced anatase doped with carbon because of the absorption in the visible spectrum that combines with long time of electron-hole recombination.
Nanosystems: Physics, Chemistry, Mathematics, 2020
Using the thermodynamic and kinetic approaches, it was found that Cu(NH 3) 2+ 4 aq complex predom... more Using the thermodynamic and kinetic approaches, it was found that Cu(NH 3) 2+ 4 aq complex predominating at 23 • C spontaneously decomposes at elevated temperatures, forming CuO precipitate in a bulk solution and a layer (CuO||SiO 2) on the surface of silica glass. The rates of these heterogeneous processes are fairly well described by the 1st-order reaction of decay of the Cu(NH 3) 2+ 4 aq complex. The formation of the CuO precipitate and layer is a two-step kinetic process. The rate of precipitate formation dominates above 65 • C while the rate of the layer formation prevails below this value. The CuO||SiO 2 material synthesized below 65 • possesses an optical bandgap of (1.25±0.05) eV, which is smaller compared to the crystals of commercial CuO. The CuO||SiO 2 material displays a photocatalytic activity in the reaction of UV-decomposition of benzoquinone-hydroquinone. It was discovered that the photocatalytic activity depends on the thickness of the photocatalyst layer.