Bismuth Valence in a Tl0.7Bi0.3Sr1.6Ba0.4CaCu2OySuperconductor from X-Ray Photoemission Spectroscopy

Zalecki, R.; Woch, W. M.; Kowalik, M.; Kołodziejczyk, Andrzej; Gritzner, G.

doi:10.12693/aphyspola.118.393

Cited by 23 publications

(7 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As shown in Figure b, the Cu peaks of the pristine and Ag-doped CuBi 2 O 4 appear at the exactly same locations, 934.1 eV (Cu 2p 3/2 ) and 954.0 eV (Cu 2p 1/2 ), indicating that Ag doping does not affect the oxidation state of Cu 2+ in the CuBi 2 O 4 structure. , However, the Bi 4f peaks in the Ag-doped sample were shifted slightly to higher binding energy by ca. 0.1 eV, suggesting that substitutional doping of Ag + into the Bi 3+ sites resulted in an increase in oxidation state of Bi to compensate the charge imbalance (Figure c). , …”

Section: Resultsmentioning

confidence: 97%

Photoelectrochemical Properties and Photostabilities of High Surface Area CuBi₂O₄ and Ag-Doped CuBi₂O₄ Photocathodes

et al. 2016

View full text Add to dashboard Cite

Electrochemical synthesis methods were developed to produce CuBi 2 O 4 , a promising p-type oxide for use in solar water splitting, as high surface area electrodes with uniform coverage. These methods involved electrodepositing nanoporous Cu/Bi films with a Cu:Bi ratio of 1:2 from dimethyl sulfoxide or ethylene glycol solutions, and thermally oxidizing them to CuBi 2 O 4 at 450 °C in air. Ag-doped CuBi 2 O 4 electrodes were also prepared by adding a trace amount of Ag + in the plating medium and codepositing Ag with the Cu/Bi films. In the Ag-doped CuBi 2 O 4 , Ag + ions substitutionally replaced Bi 3+ ions and increased the hole concentration in CuBi 2 O 4 . As a result, photocurrent enhancements for both O 2 reduction and water reduction were achieved. Furthermore, while undoped CuBi 2 O 4 electrodes suffered from anodic photocorrosion during O 2 reduction due to poor hole transport, Ag-doped CuBiO 4 effectively suppressed anodic photocorrosion. The flat-band potentials of CuBi 2 O 4 and Ag-doped CuBi 2 O 4 electrodes prepared in this study were found to be more positive than 1.3 V vs RHE in a 0.1 M NaOH solution (pH 12.8), which make these photocathodes highly attractive for use in solar hydrogen production. The optimized CuBi 2 O 4 /Ag-doped CuBi 2 O 4 photocathode showed a photocurrent onset for water reduction at 1.1 V vs RHE, achieving a photovoltage higher than 1 V for water reduction. The thermodynamic feasibility of photoexcited electrons in the conduction band of CuBi 2 O 4 to reduce water was also confirmed by detection of H 2 during photocurrent generation. This study provides new understanding for constructing improved CuBi 2 O 4 photocathodes by systematically investigating photocorrosion as well as photoelectrochemical properties of high-quality CuBi 2 O 4 and Ag-doped CuBi 2 O 4 photoelectrodes for photoreduction of both O 2 and water.

show abstract

Section: Resultsmentioning

confidence: 97%

Photoelectrochemical Properties and Photostabilities of High Surface Area CuBi₂O₄ and Ag-Doped CuBi₂O₄ Photocathodes

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The binding energy difference between the two pairs of spin-orbit peaks is about 5.4 (5.3) eV. A large separation of 2.1 eV between the two contributions of each spin-orbit photoemission signal was observed, suggesting that Bi is in a mixed valence state with Bi 3+ and Bi 5+ ion valency [36].We performed double-peak fitting for 4f 7/2 and 4f 5/2 spectra, using a χ 2 iterative program, and the concentration of Bi 3+ and Bi 5+ valence states is obtained about 55% and 45%, respectively. The Ba 3d symmetric spectra are shown in and Bi 4d core-level spectrum.…”

Section: E X-ray Photon Spectroscopymentioning

confidence: 92%

Novel optically active lead-free relaxor ferroelectric (Ba_0.6Bi_0.2Li_0.2)TiO₃

Borkar

Rao

Dutta

et al. 2016

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Abstract:We discovered a near room temperature lead-free relaxor-ferroelectric (Ba 0.6 Bi 0.2 Li 0.2 )TiO 3 (BBLT) having A-site compositional disordered ABO 3 perovskite structure. Microstructureproperty relations revealed that the chemical inhomogeneities and development of local polar nano regions (PNRs) are responsible for dielectric dispersion as a function of probe frequencies and temperatures. Rietveld analysis indicates mixed crystal structure with 80% tetragonal structure (space group P4mm) and 20% orthorhombic structure (space group Amm2) which is confirmed by the high resolution transmission electron diffraction pattern. Dielectric constant and tangent loss dispersion with and without illumination of light obey nonlinear Vogel-Fulture relation. It shows slim polarization-hysteresis (P-E) loops and excellent displacement coefficients (d 33 ~ 233 pm/V) near room temperature, which gradually diminish near the maximum dielectric dispersion temperature (T m ). The underlying physics for light-sensitive dielectric dispersion was probed by X-ray photon spectroscopy (XPS) which strongly suggests 2 that mixed valence of bismuth ions, especially Bi 5+ ions, are responsible for most of the optically active centers. Ultraviolet photoemission measurements showed most of the Ti ions are in 4+states and sit at the centers of the TiO 6 octahedra, which along with asymmetric hybridization between O 2p and Bi 6s orbitals appears to be the main driving force for net polarization. ThisBBLT material may open a new path for environmental friendly lead-free relaxor-ferroelectric research.

show abstract

“…Furthermore, in the measured sample, additional Bi 4f components (at 161.0 eV – 4f 7/2 and 166.2 eV – 4f 5/2 ) are observed. Such high binding energy values suggest the existence of Bi in pentavalent form within the surface region, which shows lower kinetic energy of emitted photoelectrons compared to Bi 3+ due to larger Coulomb attraction. , …”

Section: Resultsmentioning

confidence: 99%

“…Such high binding energy values suggest the existence of Bi in pentavalent form within the surface region, which shows lower kinetic energy of emitted photoelectrons compared to Bi 3+ due to larger Coulomb attraction. 70,71 FT-IR analysis was performed to identify the functional groups of the CM/Bi 4 O 5 Br 2 /BiOBr composites (Figure 5). A broad band in the range of 3666−3000 cm −1 corresponds to the stretching vibrations of hydroxyl groups (O−H), whereas the band at 2896 cm −1 is associated with C−H stretching.…”

Section: ■ Introductionmentioning

confidence: 99%

CelluPhot: Hybrid Cellulose−Bismuth Oxybromide Membrane for Pollutant Removal

Onwumere

Piątek

Budnyak

et al. 2020

ACS Appl. Mater. Interfaces

View full text Add to dashboard Cite

The simultaneous removal of organic and inorganic pollutants from wastewater is a complex challenge and requires usually several sequential processes. Here, we demonstrate the fabrication of a hybrid material that can fulfill both tasks: (i) the adsorption of metal ions due to the negative surface charge, and (ii) photocatalytic decomposition of organic compounds. The bioinorganic hybrid membrane consists of cellulose fibers to ensure mechanical stability and of Bi 4 O 5 Br 2 /BiOBr nanosheets. The composite is synthesized at low temperature of 115 °C directly on the cellulose membrane (CM) in order to maintain the carboxylic and hydroxyl groups on the surface that are responsible for the adsorption of metal ions. The composite can adsorb both Co(II) and Ni(II) ions and the kinetic study confirmed a good agreement of experimental data with the pseudo-second-order equation kinetic model. CM/Bi 4 O 5 Br 2 /BiOBr showed higher affinity to Co(II) ions than to Ni(II) ions from diluted aqueous solutions. The bioinorganic composite demonstrates a synergistic effect in the photocatalytic degradation of rhodamine B (RhB) by exceeding the removal efficiency of single components. The fabrication of the biologic-inorganic interface was confirmed by various analytical techniques including scanning electron microscopy (SEM), scanning transmission electron microscopy with energy dispersive X-ray spectroscopy (STEM EDX) mapping, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The presented approach for controlled formation of the bioinorganic interface between natural material (cellulose) and nanoscopic inorganic materials of tailored morphology (Bi–O–Br system) enables the significant enhancement of materials functionality.

show abstract

Bismuth Valence in a Tl_0.7Bi_0.3Sr_1.6Ba_0.4CaCu₂O_ySuperconductor from X-Ray Photoemission Spectroscopy

Cited by 23 publications

References 5 publications

Photoelectrochemical Properties and Photostabilities of High Surface Area CuBi₂O₄ and Ag-Doped CuBi₂O₄ Photocathodes

Photoelectrochemical Properties and Photostabilities of High Surface Area CuBi₂O₄ and Ag-Doped CuBi₂O₄ Photocathodes

Novel optically active lead-free relaxor ferroelectric (Ba_0.6Bi_0.2Li_0.2)TiO₃

CelluPhot: Hybrid Cellulose−Bismuth Oxybromide Membrane for Pollutant Removal

Contact Info

Product

Resources

About

Bismuth Valence in a Tl0.7Bi0.3Sr1.6Ba0.4CaCu2OySuperconductor from X-Ray Photoemission Spectroscopy

Cited by 23 publications

References 5 publications

Photoelectrochemical Properties and Photostabilities of High Surface Area CuBi2O4 and Ag-Doped CuBi2O4 Photocathodes

Photoelectrochemical Properties and Photostabilities of High Surface Area CuBi2O4 and Ag-Doped CuBi2O4 Photocathodes

Novel optically active lead-free relaxor ferroelectric (Ba0.6Bi0.2Li0.2)TiO3

CelluPhot: Hybrid Cellulose−Bismuth Oxybromide Membrane for Pollutant Removal

Contact Info

Product

Resources

About

Bismuth Valence in a Tl_0.7Bi_0.3Sr_1.6Ba_0.4CaCu₂O_ySuperconductor from X-Ray Photoemission Spectroscopy

Photoelectrochemical Properties and Photostabilities of High Surface Area CuBi₂O₄ and Ag-Doped CuBi₂O₄ Photocathodes

Photoelectrochemical Properties and Photostabilities of High Surface Area CuBi₂O₄ and Ag-Doped CuBi₂O₄ Photocathodes

Novel optically active lead-free relaxor ferroelectric (Ba_0.6Bi_0.2Li_0.2)TiO₃