139 results on '"la2cuo4"'
Search Results
2. Synthesis and electrochemical performance of La2CuO4 as a promising coating material for high voltage Li-rich layered oxide cathodes.
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Guo, Fuliang, Lu, Jiaze, Su, Meihua, Chen, Yue, Zheng, Jieyun, Yin, Liang, and Li, Hong
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ELECTROCHEMICAL electrodes , *HIGH voltages , *CATHODES , *ENERGY density , *SURFACE coatings , *LITHIUM-ion batteries - Abstract
The structural transformations, oxygen releasing and side reactions with electrolytes on the surface are considered as the main causes of the performance degradation of Li-rich layered oxides (LROs) cathodes in Li-ion batteries. Thus, stabilizing the surfaces of LROs is the key to realize their practical application in high energy density Li-ion batteries. Surface coating is regarded as one of the most effective strategies for high voltage cathodes. The ideal coating materials should prevent cathodes from electrolyte corrosion and possess both electronic and Li-ionic conductivities simultaneously. However, commonly reported coating materials are unable to balance these functions well. Herein, a new type of coating material, La2CuO4 was introduced to mitigate the surface issues of LROs for the first time, due to its superb electronic conductivity (26–35 mS⋅cm−1) and lithium-ionic diffusion coefficient (10−12–10−13 cm2⋅s−1). After coating with the La2CuO4, the capacity retention of Li1.2Ni0.54Co0.13Mn0.13O2 cathode was increased to 85.9% (compared to 79.3% of uncoated cathode) after 150 cycles in the voltage range of 2.0–4.8 V. In addition, only negligible degradations on the deliverable capacity and rate capability were observed. [ABSTRACT FROM AUTHOR]
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- 2023
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3. Thermoelectric properties of Sr‐doped LSCO for energy harvesting applications below room temperature.
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Saif, Mohd and Tripathi, Dinesh
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THERMOELECTRIC materials , *SEEBECK coefficient , *ENERGY harvesting , *ELECTRICAL resistivity , *THERMOELECTRIC power , *SCANNING electron microscopy - Abstract
Thermoelectric properties of polycrystalline La2CuO4 with (x = 0.0, 0.02, 0.05, 0.10, 0.15, 0.20) have been examined. For this, the samples have been synthesised via solid‐state reaction (SSR) technique. For microstructural analysis of investigated pellets, X‐ray diffraction and scanning electron microscopy have been performed. The electrical resistivity and Seebeck coefficient of the investigated samples have been measured with the help of an in‐house fabricated setup, capable to measure the resistivity and thermopower between 100 and 400 K with ±3% experimental uncertainty. The electrical resistivity reveals a semiconducting nature for pristine pellets. However, a transition to metallic nature of electrical resistivity is observed for Sr doping concentration ≥ 0.02. The Seebeck coefficient (S) of investigated pellets is found to be positive, which indicates holes type conduction. Apart from that, a gradual decrease in the Seebeck coefficient has also been noticed as Sr dose increases. Again, the sample with Sr concentration x = 0.02 is found to be the best with a maximum power factor value (6.947 μW/cm K2) at 165 K, which is a positive sign for future applicability of LSCO‐based oxide materials for energy harvesting applications below room temperature. [ABSTRACT FROM AUTHOR]
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- 2023
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4. Effect of Zn2+ doping on the structure and metal–insulator transition of La2CuO4 ceramics.
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Zhou, Kangjin, Wu, Ruifeng, Chang, Aimin, and Zhang, Bo
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METAL-insulator transitions , *TRANSITION metals , *TRANSITION temperature , *ELECTRON configuration , *JAHN-Teller effect , *ELECTRON distribution - Abstract
• Zn doping affects the densification, grain size, and resistivity of La 2 CuO 4 ceramics. • The Jahn-Teller distortion in the CuO 6 octahedron is mitigated after Zn doping. • Zn doping increases the Metal-insulator transition temperature (T MI) of La 2 CuO 4. The structure and electrical properties of layered perovskites La 2 Cu 1- x Zn x O 4 have been investigated. The resistivity of these samples has been measured in the temperature range of 90–300 K. The Zn2+doping induces a shift of the metal–insulator transition temperature towards the high-temperature region. The d9 electronic configuration of Cu2+ in La 2 CuO 4 leads to an uneven distribution of electron clouds, inducing axial stretching of the surrounding oxygen octahedra and resulting in Jahn-Teller distortion. After Zn2+ doping, the charge compensation induces a partial transformation of Cu2+ to Cu+. As a result, the positions occupied by Cu2+ are replaced by Zn2+ and Cu+ with perfectly symmetric electron clouds in the 3d10 outer electronic configuration, thus suppressing the Jahn-Teller effect. This shifts the phonon scattering, which is responsible for the emergence of the metal's conductive properties, to higher temperatures. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Investigations on the Thermoelectric Transport Properties in the Hole‐doped La2CuO4.
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Liu, Shan, Qin, Bingchao, Wang, Dongyang, and Zhao, Li‐Dong
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COPPER oxide , *CARRIER density , *THERMOELECTRIC materials , *THERMAL stability , *BALL mills , *DOPING agents (Chemistry) , *SEMICONDUCTORS - Abstract
Compared with the traditional thermoelectric semiconductors, the research progress of thermoelectric oxides with high‐temperature thermal stability is far behind. In this work, a layered copper oxide La2CuO4 was synthesized by combining the high‐energy ball milling, solid state reaction and spark plasma sintering. By introducing metal elements (Ba, Sr, Pb) at La site, the increased carrier concentration with optimized electrical transport properties were achieved in La2CuO4‐based thermoelectric oxides. Results showed that Ba has the best doping effect among the three dopants, with an optimal carrier concentration of ∼1020 cm−3. Furthermore, the figure of merit (ZT) value was enhanced over the entire temperature range with a maximum ZTave of ∼0.03 at 300–923 K, which is nearly two orders of magnitude higher than that of printine La2CuO4. Our research has successfully developed the thermoelectric properties of La2CuO4‐based oxide, which has the great potential to be a reliable candidate as the thermocouple for high‐temperature detection in the key parts of aircrafts. [ABSTRACT FROM AUTHOR]
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- 2022
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6. Investigations on the Thermoelectric Transport Properties in the Hole‐doped La2CuO4.
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Liu, Shan, Qin, Bingchao, Wang, Dongyang, and Zhao, Li‐Dong
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COPPER oxide ,CARRIER density ,THERMOELECTRIC materials ,THERMAL stability ,BALL mills ,DOPING agents (Chemistry) ,SEMICONDUCTORS - Abstract
Compared with the traditional thermoelectric semiconductors, the research progress of thermoelectric oxides with high‐temperature thermal stability is far behind. In this work, a layered copper oxide La2CuO4 was synthesized by combining the high‐energy ball milling, solid state reaction and spark plasma sintering. By introducing metal elements (Ba, Sr, Pb) at La site, the increased carrier concentration with optimized electrical transport properties were achieved in La2CuO4‐based thermoelectric oxides. Results showed that Ba has the best doping effect among the three dopants, with an optimal carrier concentration of ∼1020 cm−3. Furthermore, the figure of merit (ZT) value was enhanced over the entire temperature range with a maximum ZTave of ∼0.03 at 300–923 K, which is nearly two orders of magnitude higher than that of printine La2CuO4. Our research has successfully developed the thermoelectric properties of La2CuO4‐based oxide, which has the great potential to be a reliable candidate as the thermocouple for high‐temperature detection in the key parts of aircrafts. [ABSTRACT FROM AUTHOR]
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- 2022
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7. Detail Synthesis Route of Free-Standing Antiferromagnetic La2CuO4 Nanoparticles via Sol-gel Method
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Suci Winarsih, Trisna Maulana, and Budhy Kurniawan
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nanoparticles ,sol-gel ,synthesis route ,free-standing antiferromagnetic ,la2cuo4 ,Electricity and magnetism ,QC501-766 - Abstract
We report the detailed synthesis route of free-standing antiferromagnetic La2CuO4 nanoparticles by the sol-gel method. The precursors were needed to be dissolved in acid solution and continued with heating treatment to make a gel. Some catalyst was needed to control and stabilized the transformation from the solution to gel. Some heating treatments were also conducted to remove the organic component and for the nucleation process to obtain the single-phase sample. Although the sol-gel method required some additional precursors such as acid and catalyst, it has some advantages. It needed a relatively low sintering temperature and short sintering time compare to those at the solid-state reaction. Interestingly, this method can produce a sample with a good distribution of the particle size.
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- 2021
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8. The influence of Ba addition on thermal stability and catalytic activity of Cu-based mixed oxide.
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Rachele, Karen Gonçalves, Palacio, Luz Amparo, and Zotin, Fatima Maria Zanon
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CATALYTIC activity , *MIXED oxide catalysts , *X-ray absorption near edge structure , *THERMAL stability , *X-ray diffraction , *TEMPERATURE-programmed reduction , *COPPER , *BARIUM - Abstract
[Display omitted] • The partial substitution of La by Ba enhanced the thermal stability of La 2 CuO 4. • Ba addition caused structural changes creating oxygen vacancies on the surface. • XANES results showed the formation of Cu+ and Cu0 species during the reaction. • Prereduction improved catalytic activity by forming reduced species. • N 2 O is formed in lower yields as compared to noble metal-based catalysts. Catalytic reduction of NO by CO was studied over La 2-x Ba x CuO 4 (x = 0.0 or 0.4) mixed oxides prepared by coprecipitation method. The catalysts were characterized by X ray diffraction (XRD), O 2 temperature-programmed desorption (O 2 -TPD), H 2 temperature-programmed reduction (H 2 -TPR) and X-ray absorption near edge structure (XANES). NO + CO reaction was carried out in a fixed-bed flow reactor, from room temperature to 500 °C, at atmospheric pressure. Both fresh catalysts were active for the NO + CO reaction but when were submitted to thermal aging, the barium free catalyst significantly lost its activity. The partial substitution of La by Ba enhanced the thermal stability and although the activity of the catalyst has decreased, it remains high, approaching 100 % at 500 °C. These results can be associated with reducible copper species observed by XANES in the thermal aged catalyst containing Ba. [ABSTRACT FROM AUTHOR]
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- 2021
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9. Effect of Co2+ doping on structural, optical and photocatalytic properties of La2CuO4 perovskite.
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Parida, Sridhar, Nanda, Jyotirmayee, and Sarangi, Biswaprakash
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OPTICAL properties , *METHYLENE blue , *X-ray photoelectron spectroscopy , *PEROVSKITE , *COPPER , *SOL-gel processes , *DYES & dyeing - Abstract
• La 2 Cu 1-x Co x O 4 (x = 0–0.15) perovskites synthesized via sol–gel autocombustion method. • XRD and FTIR confirm orthorhombic structure in prepared materials. • Optical energy bandgaps range from 1.31 to 1.04 eV, indicating semiconducting nature. • 15% Co-doped sample shows enhanced sunlight-driven methylene blue degradation. In this article, structural, optical and photocatalytic properties of a series of Co2+ doped La 2 CuO 4 perovskites, synthesized via sol–gel auto-combustion method, have been investigated for the first time. Structural and Fourier-transform infrared (FTIR) studies revealed pure orthorhombic phase formation with smaller crystallite sizes at higher Co2+ concentrations. Elemental composition was confirmed by energy-dispersive X-ray (EDX) analysis, and X-ray photoelectron spectroscopy (XPS) studies indicated the possible oxidation states of the constituent elements. The optical energy band gaps were estimated to be 1.31–1.04 eV, indicating the semiconducting nature and proper bandgap tuning with increased Co2+ content of the prepared perovskites. The highest photocatalytic methylene blue dye degradation efficiency, about 90%, was achieved for the 15% Co2+ doped La 2 CuO 4 perovskite, indicating its potential use as a photocatalyst for environmental remediation. [ABSTRACT FROM AUTHOR]
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- 2024
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10. Optimized nano-perovskite lanthanum cuprate decorated PVA based solid polymer electrolyte.
- Author
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Al-Gunaid, Murad Q.A., T.E, Somesh, H.M, Gayitri, Al-Ostoot, Fares Hezam, and Basavarajaiah, Siddaramaiah
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Solid polymeric electrolytes (SPEs) based on PVA/2wt% La2CuO4 with 5, 10 and 15 wt% of LiClO4 have been fabricated via solution intercalation technique. TEM result indicates that the size of nanoparticles (NPs) lies in the range 91–134 nm. The morphological behavior of PVA-SPEs probed by SEM; where the roughness of SPE films increased with increase in LiClO4 contents. The structural behaviors of SPEs have been elucidated by XRD, while ion-dipole interactions between components were evaluated by FTIR. The optical properties of SPEs investigated by UV-visible spectroscopy, where the outcomes showed increased refractive index from 1.74 to 2.41, whereas the band gap energy (Eg) is reduced from 5.26 to 3.32e V for PVA and PVA/2wt% La2CuO4/15wt%LiClO4, respectively. Electrical properties of the SPEs evaluated using LCR-meter at room temperature in frequency range 50 Hz–5 MHz. The ac-conductivity (σac) strongly depends on frequency and LiClO4 contents in SPEs and the maximum σac achieved is 2.82X10–5 Scm–1 for 15wt% LiClO4 doped PVA/La2CuO4 film. The current-voltage (I-V) data indicated non-ohmic behaviors at higher potential voltage region (> 6 V) and dc-conductivity (σdc) increased with increase in dosage of LiClO4 in SPEs through hopping ions mechanism. Thermal properties of the SPEs have been evaluated using DSC and TGA. The reduction in Tg of flexible SPEs with increase in LiClO4 content was observed due to amorphous portion dominates in SPEs. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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11. Synergistic effects of interface and valence state on boosting electrochemical CO2 reduction activity of La2CuO4.
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Bian, Shiya, Jin, Xuekun, Mi, Jinxing, Chen, Fengjuan, Cai, Li, Wang, Ziyu, Li, Junhua, and Chen, Jianjun
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ELECTROLYTIC reduction , *STANDARD hydrogen electrode , *CARBON dioxide , *COPPER oxide , *SOL-gel processes , *SURFACE structure - Abstract
The electrochemical CO 2 reduction reaction (CER) to methane (CH 4) has received great attention. Here, we proposed an efficient method to facilitate the conversion of CO 2 -to-CH 4 by creating a two-phase interface over urea-modified La 2 CuO 4 catalyst. The most optimized one exhibits the highest selectivity (22%) for CH 4 and the best activity (14 mA cm−2) and stability (5 h) at the potential of −1 V vs. reversible hydrogen electrode. The enhanced CER performance can be attributed to the establishment of interfacial effect within the two-phase, which facilitates the reduction of Cu2+ and promotes the active sites concentration. The 3 U-La 2 CuO 4 catalyst with La 2 O 3 /La 2 CuO 4 interfaces, which exhibits the highest selectivity (35%) for CH 4 and the best activity (14 mA·cm−2) and stability (5 h) at the potential of −1 V vs. reversible hydrogen electrode (RHE) in CER than La 2 CuO 4. [Display omitted] • 3 U-La 2 CuO 4 could be successfully synthesized by sol-gel method. • In 3 U-La 2 CuO 4 , La 2 O 3 is deposited on the of La 2 CuO 4 surface with two-phase structure. • The two-phase interface produced by 3 U-La 2 CuO 4 promotes the reduction of Cu2+. • 3 U-La 2 CuO 4 exhibits good CER activity with high stability. [ABSTRACT FROM AUTHOR]
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- 2024
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12. Tetracycline hydrochloride degradation by activation of peroxymonosulfate with lanthanum copper Ruddlesden-Popper perovskite oxide: Performance and mechanism.
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Xia, Yitian, Li, Xiaoming, Wu, You, Chen, Zhuo, Pi, Zhoujie, Duan, Abing, and Liu, Junwu
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COPPER , *LANTHANUM , *ELECTRON paramagnetic resonance , *PEROXYMONOSULFATE , *TETRACYCLINE , *DRINKING water purification - Abstract
ABO 3 -type perovskite oxides have been regarded as a kind of potential catalyst for peroxymonosulfate (PMS) activation. But some limitations such as specific pH conditions and coexisting ion interference restrict its practical application. Herein, a lanthanum copper Ruddlesden-Popper perovskite oxide (La 2 CuO 4) was successfully synthesized through the sol-gel process and applied in the activation of PMS. And for the first time the La 2 CuO 4 /PMS system was used for tetracycline hydrochloride (TC-HCl) degradation. Results showed that La 2 CuO 4 was a potential PMS activation catalyst in the removal of antibiotics. At optimized condition (0.2 g/L catalysts, 1 mM PMS, pH 0 6.9), 96.05% of TC-HCl was removed in 30 min. In experiments of debugging control conditions, over a wide pH range of 3–11, more than 90% of TC-HCl can be removed. In the natural water treatment process, TC-HCl removal rates of about 84.2% and 70.3% were obtained in tap water and River water, respectively. According to the reusability and stability tests and the results of FTIR and XPS analysis, La 2 CuO 4 had high structural and chemical stability. Electron paramagnetic resonance (EPR) suggested that the active species including · O H , S O 4 − · and 1 O 2 were detected in degradation reaction. Finally, reasonable reaction mechanisms and possible degradation pathways of TC-HCl were proposed. These results indicate that La 2 CuO 4 can act as a potential catalyst for PMS activation to degrade TC-HCl in water. [Display omitted] • La 2 CuO 4 was first applied in TC-HCl degradation by activation of PMS. • La 2 CuO 4 /PMS maintained high TC-HCl degradation efficiency in wide range of pH. • La 2 CuO 4 /PMS has great application potential in reagent water. • The reaction mechanism of La 2 CuO 4 /PMS/antibiotics degradation was studied. [ABSTRACT FROM AUTHOR]
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- 2023
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13. HP -- A code for the calculation of Hubbard parameters using density-functional perturbation theory
- Author
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Iurii Timrov, Nicola Marzari, and Matteo Cococcioni
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pseudopotentials ,Condensed Matter - Materials Science ,model ,la2cuo4 ,electronic-structure ,spectra ,hubbard parameters ,General Physics and Astronomy ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,self -interaction corrections ,dynamics ,infrastructure ,quantum espresso ,open -source software ,density -functional perturbation theory ,Hardware and Architecture ,linear -response theory ,lda+u method ,open science ,transition -metal compounds ,systems ,implementation - Abstract
We introduce HP, an implementation of density-functional perturbation theory, designed to compute Hubbard parameters (on-site U and inter-site V ) in the framework of DFT+U and DFT+U+V. The code does not require the use of computationally expensive supercells of the traditional linear-response approach; instead, unit cells are used with monochromatic perturbations that significantly reduce the computational cost of determining Hubbard parameters. HP is an open-source software distributed under the terms of the GPL as a component of QUANTUM ESPRESSO. As with other components, HP is optimized to run on a variety of different platforms, from laptops to massively parallel architectures, using native mathematical libraries (LAPACK and FFTW) and a hierarchy of custom parallelization layers built on top of MPI. The effectiveness of the code is showcased by computing Hubbard parameters self-consistently for the phospho-olivine LixMn1/2Fe1/2PO4 (x = 0, 1/2, 1) and by highlighting the accuracy of predictions of the geometry and Li intercalation voltages. Program summaryProgram Title: HP CPC Library link to program files: https://doi .org /10 .17632 /xsbtkpknf7 .1 Licensing provisions: GNU General Public License v 2.0 Programming language: Fortran 95 External routines: HP is a tightly integrated component of the QUANTUM ESPRESSO distribution and requires the standard libraries linked by it: BLAS, LAPACK, FFTW, MPI.Nature of problem: Calculation of Hubbard interaction parameters for DFT+U and DFT+U+V.Solution method: Hubbard parameters are expressed in terms of the inverse response matrices to localized perturbations of the atomic occupations. The response matrices are computed using densityfunctional perturbation theory to first order (linear-response theory) in the reciprocal space, that allows to reconstruct the response to a localized perturbation (obtained from calculations in an appropriately sized supercell) as the superposition of the responses to a series of monochromatic perturbations in a primitive unit cell, thus reducing significantly the computational cost. The response matrices are computed via a self-consistent solution of the static Sternheimer equation, whose implementation does not require the calculation of any virtual states. Pseudopotentials (norm-conserving, ultrasoft, projector augmented wave) are used in conjunction with plane-wave basis sets and periodic boundary conditions. Additional comments including restrictions and unusual features: Local and semi-local exchange-correlation kernels only. Noncollinear spin-polarized formalism is not supported, only collinear spin-polarized or non-spin-polarized cases can be treated. Spin-orbit coupling cannot be used. Calculation of Hund's J is not supported. Multiple Hubbard channels per atom are not supported. The Hubbard manifold can be only constructed on atomic orbitals, both orthogonalized and non-orthogonalized, while Wannier functions (as well as other localized basis sets) are not supported. The linear-response approach we adopt here typically results in Hubbard parameters that are unphysically large for closed shell states [1]. No virtual orbitals are used, nor even calculated.The distribution file of this program can be downloaded from the QUANTUM ESPRESSO website: http:// www.quantum -espresso .org/, and the development version of this program can be downloaded via Git from the GitLab website: https://gitlab .com /QEF /q-e. Interactions with end users of the HP code happen via a mailing-list forum of QUANTUM ESPRESSO: https://www.quantum -espresso .org /forum., Documentation of the HP code is tightly coupled with the code and is done via standard code comments; different subroutines that implement different equations of the DFPT formalism contain references to the two main papers [2,3] describing in detail theory behind the implementation.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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- 2022
14. Cu-based perovskite as a novel CWPO catalyst for petroleum refining wastewater treatment: Performance, toxicity and mechanism.
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Ma, Wencheng, Zhang, Shaobo, Deng, Liming, Zhong, Dan, Li, Kefei, Liu, Xiaotong, Li, Jinxin, Zhang, Jingna, and Ma, Jun
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PETROLEUM refining , *WASTEWATER treatment , *GAS chromatography/Mass spectrometry (GC-MS) , *X-ray photoelectron spectroscopy , *PEROVSKITE , *SOLAR cell efficiency , *SOLAR cells - Abstract
For the first time, Cu-based perovskite oxides were used as catalysts to treat highly toxic and refractory petroleum refining wastewater based on catalytic wet peroxide oxidation (CWPO) technology. Perovskite La 2 CuO 4 was synthesized by sol-gel method. A series of characterizations showed that the synthesized catalyst particles are tetragonal phase perovskite structure. The experimental results showed that under the conditions of catalyst dosage of 0.75 g, temperature of 100 ℃ and reaction time of 30 min, the COD removal rate was 89.58 %, the TOC removal rate was 87.38 %. The morphology and structure of the catalyst before and after the reaction proved that the catalyst has strong stability and catalytic activity. The components of raw water, Wet Air Oxidation (WAO) effluent and CWPO effluent were compared and analyzed by Gas Chromatography-Mass Spectrometry (GC-MS), and the possible mechanism and path of WAO and CWPO degradation of petroleum refining wastewater were further explored. The changes of Cu components in La 2 CuO 4 before and after CWPO reaction and the transformation of lattice oxygen and adsorbed oxygen were analyzed by X-ray Photoelectron Spectroscopy (XPS). The involvement of Cu (Ⅱ) /Cu (Ⅰ) in the activation of H 2 O 2 was speculated. Finally, the biotoxicity of raw water, WAO effluent and CWPO effluent was predicted. The results provide reference value for the application of catalyst La 2 CuO 4 in various petrochemical wastewater. [Display omitted] • La 2 CuO 4 was first used as a catalyst in the CWPO process for wastewater treatment. • The catalyst La 2 CuO 4 shows strong catalytic activity and stability. • The synthesized catalyst particles had a tetragonal phase perovskite structure. • Under the optimum condition, the COD removal rate of CWPO effluent is 89.58 %. [ABSTRACT FROM AUTHOR]
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- 2023
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15. Properties of La2-xSrxCuO4(x=0.0-0.25) oxidized by electrochemical method
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Fukuoka, A., Tokiwa-Yamamoto, A., Usami, R., Liu, C.-J., Yamauchi, H., Fujita, Toshizo, editor, and Shiohara, Yuh, editor
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- 1994
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16. Electrochemical Oxidation of La2-x Ba x CuO4 (0≤x≤0.145)
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Itoh, Mitsuru, Shan, Yue-Jin, Sakamoto, Shigeru, Ishiyama, Osamu, Inaguma, Yoshiyuki, Nakamura, Tetsurō, Fujita, Toshizo, editor, and Shiohara, Yuh, editor
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- 1994
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17. Surface Structure and Chemistry of Cuprate Superconductors
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Liang, Wei Yao, Zhou, Wuzong, Bando, Yoshichika, editor, and Yamauchi, Hisao, editor
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- 1993
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18. Mott-Hubbard Band and Charge Transfer Gap in La2CuO4
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Kataoka, Mitsuo, Kajimura, Koji, editor, and Hayakawa, Hisao, editor
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- 1991
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19. Perovskite oxide LaMO3-δ (M = Fe, Co, Ni and Cu) cathode for efficient electroreduction of nitrate.
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Yang, Wen-Jian, Yang, Li-Hui, Peng, Han-Jun, Lv, Si-Hao, Muhammad Adeel Sharif, Hafiz, Sun, Wei, Li, Wei, Yang, Cao, and Lin, Hui
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ELECTROLYTIC reduction , *CATHODES , *OXIDATION-reduction reaction , *ELECTRON sources , *OXIDES , *CATALYTIC activity , *PEROVSKITE - Abstract
[Display omitted] • Perovskite oxide LaMO 3-δ cathodes were applied for NO 3 –-N electroreduction. • La 2 CuO 4 exhibited best catalytic performance as its super electrochemical property. • The selectivity of NH 4 +-N and N 2 were 82.4 ± 2.2% and 9.4 ± 2.4%, respectively. • Both electron- and H*-mediated pathway occurred for NO 3 –-N electroreduction. • Oxygen vacancies and redox cycle of Cu(I)-Cu(II)-Cu(I) worked for NO 3 –-N reduction. Electroreduction removal of nitrate (NO 3 –-N) is considered as a promising approach to solve its adverse effects on environment and human health, where efficient and cheap catalysts are required. Perovskite-based catalysts showed a versatile catalytic ability for wide range of redox reactions, but seldom applied for NO 3 –-N reduction. Herein, four perovskite oxide cathodes, LaMO 3-δ (M = Fe, Co, Ni and Cu) were prepared and used for the reduction of NO 3 –-N. The Ruddlesden-Popper (RP) type La 2 CuO 4 exhibited the best NO 3 –-N catalytic activity among the four perovskite oxide cathodes, with a removal rate of 11.7 × 10-3 min−1. The high selectivity of NH 4 +-N (82.4 ± 2.2%) indicated that NH 4 +-N was the main final product for NO 3 –-N electroreduction at La 2 CuO 4 cathode, but 100% of N 2 selectivity could be obtained with addition of 1000 and 1500 mg/L Cl- as the electro-assisted chlorination process. The mechanism of NO 3 –-N electroreduction occurred by both electron- and H*-mediated pathway, and the oxygen vacancies and redox cycle of Cu(I)-Cu(II)-Cu(I) were proposed as the accommodation sties and direct electron sources for NO 3 –-N reduction. Generally, this study opens a novel avenue for the development of earth-abundant, cost-effective catalyst with effective NO 3 –-N electroreduction. [ABSTRACT FROM AUTHOR]
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- 2022
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20. Selective conversion of glycerol to hydroxyacetone in gas phase over La2CuO4 catalyst.
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Velasquez, Mauricio, Santamaria, Alexander, and Batiot-Dupeyrat, Catherine
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GLYCERIN , *HYDROXYPROPANONE , *GAS phase reactions , *COPPER oxide , *METAL catalysts , *DEHYDRATION reactions - Abstract
The gas phase dehydration of glycerol to hydroxyacetone was investigated over La2CuO4 catalyst under inert conditions. The reaction was performed in the temperature range of 260-400 °C. At low temperature (260 and 280 °C) high yields of hydroxyacetone can be achieved: 76% while at higher temperatures carbon deposition occurred. We showed that the structure of the La2CuO4 catalyst was modified during time on stream: Cu2+ was partially reduced into Cu1+ even at 260 °C. The formation of Cu2O was revealed by XRD and XPS analysis confirmed that both Cu2+ and Cu1+ are present at the surface of the catalyst. After reduction of La2CuO4 into Cu0/La2O3, low catalytic activity was observed proving that metallic copper is not the required species to perform the dehydration of glycerol into hydroxyacetone under our experimental conditions. TGA analysis revealed that only small amount of carbon deposition occurred during time on stream at 260 °C, no catalytic deactivation being observed during 20 h of reaction. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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21. Effects of YSZ addition on the response of La2CuO4 sensing electrode for a potentiometric NO x sensor.
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Chen, Ying and Xiao, Jianzhong
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YTTRIA stabilized zirconium oxide , *ADDITION reactions , *LANTHANUM compounds , *COPPER oxide , *CHEMICAL detectors , *COPPER electrodes , *POTENTIOMETRY , *NITROGEN oxides - Abstract
Abstract: This study describes the effects of YSZ addition on the response of potentiometric gas sensor based on La2CuO4 sensing electrode. The YSZ with four concentrations (0, 2, 5 and 10vol.%) are respectively added into La2CuO4 to enlarge the larger superficial area of the triple phase boundary (TPB). Obtained sensors are all highly sensitive to NO and NO2, but no responses to O2 and CO2. The biggest NO sensing is obtained by the sensor fabricated with 5vol.% YSZ addition at 400°C. This response behavior agrees with the scanning electron microscope and EDS spectrum results, indicating that appropriate superficial area of TPB can improve the sensor performance. In addition, the complex impedance of the sensor verifies that the triple phase boundary plays an important role on NO detection. Four sensors are all NO selective against O2, but their sensitivities are affected by CO2, CO and NO2. Interestingly, the response values and slopes of the sensor fabricated with 5vol.% YSZ addition are always bigger than those of the sensor fabricated with pure La2CuO4 in the cases of NO selectivity against CO2 and CO. [Copyright &y& Elsevier]
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- 2014
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22. Effect of Thermal Stresses Formed during Air Annealing of Amorphous Lanthanum Cuprate Thin Films Deposited on Silicon Substrate
- Author
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Jean-Philippe Bauer, Pascal Boulet, Jean-François Pierson, Philippe Steyer, Fabien Capon, Annie Malchere, Nolwenn Tranvouez, Institut Jean Lamour (IJL), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Materials science ,Silicon ,genetic structures ,crystallization ,Annealing (metallurgy) ,chemistry.chemical_element ,02 engineering and technology ,01 natural sciences ,Thermal expansion ,law.invention ,[SPI.MAT]Engineering Sciences [physics]/Materials ,law ,0103 physical sciences ,Materials Chemistry ,Thin film ,Composite material ,Crystallization ,Environmental scanning electron microscope ,010302 applied physics ,Surfaces and Interfaces ,[CHIM.MATE]Chemical Sciences/Material chemistry ,Sputter deposition ,021001 nanoscience & nanotechnology ,eye diseases ,Surfaces, Coatings and Films ,Amorphous solid ,thermo-mechanical properties ,chemistry ,thin films ,lcsh:TA1-2040 ,La2CuO4 ,sense organs ,lcsh:Engineering (General). Civil engineering (General) ,0210 nano-technology - Abstract
Amorphous thin films of La&ndash, Cu&ndash, O deposited by magnetron sputtering have been annealed at different temperatures and in situ analyzed by X-ray diffraction. These experiments were useful to determine the crystallization temperature and to follow the crystallization process of the film. The in situ annealing X-ray diffraction analyses have been also used to determine the thermal expansion coefficient of La2CuO4 thin film. The estimated value is close to that obtained for a commercial powder. The thermal expansion coefficient value with additional environmental scanning electron microscopy observations explains the delamination origin that occurs during the annealing before the crystallization step. The buckling and delamination of the film observed is caused by the thermal expansion coefficient mismatch of the film and the substrate. During the heating step, the mismatch generates compressive stress at the film/substrate interface, causing the film to lift off and crack in the typical way.
- Published
- 2020
- Full Text
- View/download PDF
23. Simulación de segundos principios del estado electrónico de láminas de CuO2
- Author
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Ruiz Laborda, Guillermo, García Fernández, Pablo (físico), and Universidad de Cantabria
- Subjects
Second-principles ,Spin correlation ,Monte Carlo de cadena de Markov ,Superconductividad de alta temperatura ,Correlación de spin ,La2CuO4 ,Markov Chain Monte Carlo ,Segundos principios ,Transición de fase ,High-temperature superconductivity ,Phase transition - Abstract
The phenomenon of superconductivity was firstly observed over one century ago, and since then it has become one of the most important fields of study of Solid State Physics. For decades, the BCS theory was able to explain the mechanism that leads to this phenomenon in certain compounds, called conventional superconductors. However, the discovery of high-temperature superconductivity in 1986 by Bednorz and Müller evidenced that the BCS theory itself, and still no one, is capable to wholly explain superconductivity. In this work, we have studied the electronic structure of CuO2 layers like those appearing in La2CuO4, one of the reference materials for high-temperature superconductivity. These cuprate superconductors exhibit a characteristic phase diagram with hole doping and temperature as axes. By means of a simple model, combining both second-principles techniques and a Markov Chain Monte Carlo, we have focused on the region of the aforementioned phase diagram where the system is not doped with holes. These elements combined have served us to computationally reproduce a simultaneous antiferromagnetic-paramagnetic and insulator-metal phase transition. RESUMEN: El fenómeno de la superconductividad fue observado por primera vez hace más de un siglo, y desde entonces se ha convertido en uno de los campos de estudio más importantes de la Física de Estado Sólido. Durante décadas, la teoría BCS fue capaz de explicar el mecanismo que causa este fenómeno en un cierto número de compuestos, llamados superconductores convencionales. Sin embargo, el descubrimiento de la superconductividad de alta temperatura en 1986 por Bednorz y Müller evidenció que la teoría BCS por sí misma, y aún hoy día ninguna, es capaz de explicar completamente la superconductividad. En este trabajo, hemos estudiado la estructura electrónica de láminas de CuO2 como las que aparecen en La2CuO4, uno de los superconductores de alta temperatura de referencia. Estos cupratos superconductores presentan un diagrama de fase característico cuyos ejes son el dopaje con huecos y la temperatura. Por medio de un modelo sencillo, combinando tanto técnicas de segundos principios como un método Monte Carlo de cadena de Markov, nos hemos centrado en la región del mencionado diagrama de fases en donde el sistema no está dopado con huecos. La combinación de estos elementos nos ha servido para reproducir, computacionalmente, una transición de fase simultánea: antiferromagnético-paramagnético y aislante-metal. Grado en Física
- Published
- 2020
24. Pulay forces in density-functional theory with extended Hubbard functionals: From nonorthogonalized to orthogonalized manifolds
- Author
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Nicola Marzari, Iurii Timrov, Matteo Cococcioni, Luca Binci, and Francesco Aquilante
- Subjects
Lyapunov function ,pseudopotentials ,self-interaction ,electronic-structure ,spectra ,FOS: Physical sciences ,02 engineering and technology ,Orbital overlap ,01 natural sciences ,Condensed Matter - Strongly Correlated Electrons ,Matrix (mathematics) ,symbols.namesake ,Atomic orbital ,0103 physical sciences ,010306 general physics ,implementation ,Basis set ,Physics ,parameters ,Condensed Matter - Materials Science ,la2cuo4 ,Strongly Correlated Electrons (cond-mat.str-el) ,Finite difference ,Materials Science (cond-mat.mtrl-sci) ,021001 nanoscience & nanotechnology ,Manifold ,potentials ,Classical mechanics ,lda+u method ,symbols ,systems ,Density functional theory ,Condensed Matter::Strongly Correlated Electrons ,0210 nano-technology - Abstract
We present a derivation of the exact expression for Pulay forces in density-functional theory calculations augmented with extended Hubbard functionals, and arising from the use of orthogonalized atomic orbitals as projectors for the Hubbard manifold. The derivative of the inverse square root of the orbital overlap matrix is obtained as a closed-form solution of the associated Lyapunov (Sylvester) equation. The expression for the resulting contribution to the forces is presented in the framework of ultrasoft pseudopotentials and the projector-augmented-wave method, and using a plane wave basis set. We have benchmarked the present implementation with respect to finite differences of total energies for the case of NiO, finding excellent agreement. Owing to the accuracy of Hubbard-corrected density-functional theory calculations - provided the Hubbard parameters are computed for the manifold under consideration - the present work paves the way for systematic studies of solid-state and molecular transition-metal and rare-earth compounds., Comment: 16 pages, 1 figure
- Published
- 2020
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25. Self-consistent Hubbard parameters from density-functional perturbation theory in the ultrasoft and projector-augmented wave formulations
- Author
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Matteo Cococcioni, Nicola Marzari, and Iurii Timrov
- Subjects
ab-initio ,pseudopotentials ,electronic-structure ,spectra ,Perturbation (astronomy) ,metals ,FOS: Physical sciences ,Primitive cell ,02 engineering and technology ,Crystal structure ,Self consistent ,01 natural sciences ,law.invention ,law ,Quantum mechanics ,0103 physical sciences ,strongly correlated systems ,010306 general physics ,Physics ,Condensed Matter::Quantum Gases ,Condensed Matter - Materials Science ,model ,la2cuo4 ,Materials Science (cond-mat.mtrl-sci) ,dynamics ,021001 nanoscience & nanotechnology ,Formalism (philosophy of mathematics) ,Projector ,lda+u method ,Condensed Matter::Strongly Correlated Electrons ,Monochromatic color ,0210 nano-technology - Abstract
The self-consistent evaluation of Hubbard parameters using linear-response theory is crucial for quantitatively predictive calculations based on Hubbard-corrected density-functional theory. Here, we extend a recently-introduced approach based on density-functional perturbation theory (DFPT) for the calculation of the on-site Hubbard $U$ to also compute the inter-site Hubbard $V$. DFPT allows to reduce significantly computational costs, improve numerical accuracy, and fully automate the calculation of the Hubbard parameters by recasting the linear response of a localized perturbation into an array of monochromatic perturbations that can be calculated in the primitive cell. In addition, here we generalize the entire formalism from norm-conserving to ultrasoft and projector-augmented wave formulations, and to metallic ground states. After benchmarking DFPT against the conventional real-space Hubbard linear response in a supercell, we demonstrate the effectiveness of the present extended Hubbard formulation in determining the equilibrium crystal structure of Li$_x$MnPO$_4$ (x=0,1) and the subtle energetics of Li intercalation., Comment: 15 pages, 3 figures
- Published
- 2020
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26. Synthesis of Cu2O/La2CuO4 nanocomposite as an effective heterostructure photocatalyst for H2 production.
- Author
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Zhang, Zizhong, Chen, Xiaohong, Zhang, Xianwen, Lin, Huaxiang, Lin, Huan, Zhou, Yangen, and Wang, Xuxu
- Subjects
- *
COPPER compounds synthesis , *HETEROSTRUCTURES , *PHOTOCATALYSTS , *HYDROGEN production , *PEROVSKITE , *HIGH temperature superconductors - Abstract
Abstract: A perovskite-like compound La2CuO4-based material, a well-known high-temperature superconductor, was studied as a photocatalyst. H2 was produced over La2CuO4 from aqueous solutions containing methanol as a sacrificial reagent under high-pressure Hg lamp irradiation. The photocatalytic activity of La2CuO4 is superior to that of the commercial anatase TiO2, and can be greatly improved by loading with Cu2O. Photoelectrochemical measurements revealed that the conduction band minimum of the La2CuO4 photocatalysts is thermodynamically feasible for the reduction reaction of water and Cu2O efficiently increase the electron–hole separation on La2CuO4 under photon irradiation to account for its higher photocatalytic activity. [Copyright &y& Elsevier]
- Published
- 2013
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27. Optical properties of La2CuO4 and La2−xCaxCuO4 crystallites in UV–vis–NIR region synthesized by sol–gel process
- Author
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Li, Yifeng, Huang, Jianfeng, Cao, Liyun, Wu, Jianpeng, and Fei, Jie
- Subjects
- *
CRYSTAL optics , *X-ray diffraction , *CRYSTAL structure , *HEAT treatment , *NEAR infrared spectroscopy , *SOLUBILITY , *ABSORPTION , *SOL-gel processes - Abstract
Abstract: La2CuO4 and La2−xCaxCuO4 crystallites were prepared via a simple sol–gel process. The as-prepared La2CuO4 and La2−xCaxCuO4 crystallites were characterized by X-ray diffraction, transmission electron microscope and UV–vis–NIR spectra. Results show that the grain size of La2CuO4 crystallites increases with the increase of heat treatment temperature from 600°C to 800°C. Optical properties show that La2CuO4 crystallites have broad absorption both in the UV–vis region and in the NIR region. The band gap of the as-prepared crystallites decreases from 1.367eV to 1.284eV with the increase of calcination temperature from 600°C to 800°C. In the series of La2−xCaxCuO4 compounds (x=0.05, 0.08, 0.10, 0.12, 0.15 and 0.20), all of the samples exhibit an orthogonal crystal structure and the solubility limit of Ca2+ in La2CuO4 is within the range of x=0.12–0.15. In the whole UV–vis–NIR region, La2−xCaxCuO4 crystallites exhibit a broad absorption and the corresponding band gap first increases and then decreases with increasing of Ca2+ content. [Copyright &y& Elsevier]
- Published
- 2012
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28. La2CuO4 sensing electrode configuration influence on sensitivity and selectivity for a multifunctional potentiometric gas sensor
- Author
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Macam, Eric R., White, Briggs M., Blackburn, Bryan M., Di Bartolomeo, Elisabetta, Traversa, Enrico, and Wachsman, Eric D.
- Subjects
- *
LANTHANUM compounds , *COPPER oxide , *ELECTRODES , *POTENTIOMETRY , *GAS detectors , *ELECTRIC contacts , *PLATINUM - Abstract
Abstract: The effects of electrical contact configuration for La2CuO4 sensing electrodes for a planar-based potentiometric gas sensor were studied in order to further quantify the effects of processing on sensor performance. Five configurations of La2CuO4 were used for the sensing electrode. The La2CuO4 sensing electrode was screen printed opposite a Pt counter electrode on a tape cast YSZ electrolyte. Three sensors were prepared for each configuration to test repeatability. Each sensor was tested at temperatures from 400 to 700°C at various concentrations of NO2, NO, and CO in an environment of 3% O2 with a balance of N2. Results show that these sensors exhibit suitable sensitivity to all the gases tested. More importantly, it was shown that the sensitivity, selectivity/cross-sensitivity, and repeatability of these sensors are dependent on the sensing electrode configuration. [Copyright &y& Elsevier]
- Published
- 2011
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29. Effect of La2CuO4 electrode area on potentiometric NO x sensor response and its implications on sensing mechanism
- Author
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Macam, Eric R., Blackburn, Bryan M., and Wachsman, Eric D.
- Subjects
- *
LANTHANUM compounds , *ELECTRODES , *POTENTIOMETRY , *NITRIC oxide , *GAS detectors , *IMPEDANCE spectroscopy , *ASYMMETRY (Chemistry) , *ELECTROCHEMISTRY - Abstract
Abstract: The intent of this work is to look at the effects of varying the La2CuO4 electrode area and the asymmetry between the sensing and counter electrode in a solid state potentiometric sensor with respect to NO x sensitivity. NO2 sensitivity was observed at 500–600°C with a maximum sensitivity of ∼22mV/decade [NO2] observed at 500°C for the sensor with a La2CuO4 electrode area of ∼30mm2. The relationship between NO2 sensitivity and area is nearly parabolic at 500°C, decreases linearly with increasing electrode area at 600°C, and was a mixture of parabolic and linear behavior 550°C. NO sensitivity varied non-linearly with electrode area with a minima (maximum sensitivity) of ∼−22mV/decade [NO] at 450°C for the sensor with a La2CuO4 electrode area of 16mm2. The behavior at 400°C was similar to that of 450°C, but with smaller sensitivities due to a saturation effect. At 500°C, NO sensitivity decreases linearly with area. We also used electrochemical impedance spectroscopy (EIS) to investigate the electrochemical processes that are affected when the sensing electrode area is changed. Changes in impedance with exposure to NO x were attributed to either changes in La2CuO4 conductivity due to gas adsorption (high frequency impedance) or electrocatalysis occurring at the electrode/electrolyte interface (total electrode impedance). NO2 caused a decrease in high frequency impedance while NO caused an increase. In contrast, NO2 and NO both caused a decrease in the total electrode impedance. The effect of area on both the potentiometric and impedance responses show relationships that can be explained through the mechanistic contributions included in differential electrode equilibria. [Copyright &y& Elsevier]
- Published
- 2011
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30. The effect of La2CuO4 sensing electrode thickness on a potentiometric NO x sensor response
- Author
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Macam, Eric R., Blackburn, Bryan M., and Wachsman, Eric D.
- Subjects
- *
POTENTIOMETRY , *NITRIC oxide , *THICKNESS measurement , *LANTHANUM compounds , *SOLID state chemistry , *GAS detectors , *TEMPERATURE effect , *PLATINUM electrodes - Abstract
Abstract: In order to further understand the different contributions to NOx sensing mechanism as well as the importance of electrode geometry, solid state potentiometric sensors with varying La2CuO4 sensing electrode thicknesses were studied. These sensors (with a Pt counter electrode) showed a dependence of NO2 sensitivity which decreased with increasing thickness in the temperature range of 550–650°C. They also showed NO sensitivity that was independent of thickness at 400°C and 600°C, but varied at temperatures between. This behavior was attributed to multiple mechanistic contributions explained by Differential Electrode Equilibria. [Copyright &y& Elsevier]
- Published
- 2011
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31. Synthesis of CuO, La2O3, and La2CuO4 by the Thermal-Decomposition of Oxalates Precursors Using a New Method.
- Author
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Abboudi, Mostafa, Messali, Mouslim, Kadiri, Naima, Ali, AbdelouahidBen, and Moran, Emilio
- Subjects
- *
COMPLEX compounds synthesis , *CHEMICAL decomposition , *THERMAL analysis , *OXALATES , *OXALIC acid , *COPPER oxide , *LANTHANUM compounds , *CHEMICAL reactions - Abstract
A new procedure to prepare oxides materials from oxalates complexes precursors is presented. Detailed description of the method is reported, illustrated with examples of the preparation of oxides. A solid-solid reaction between the oxalic acid and nitrate salt of metal leads to the formation of the corresponding oxalate. These oxalates are used as precursors and are heated to form the corresponding oxides by thermal-decomposition. This article relates the first examples of oxides prepared by this new method: the synthesis of the copper oxide CuO, the hexagonal phase of lanthanum oxide La2O3, and the lanthanum cuprate La2CuO4. All the samples are characterized by SEM and XRD. Thermal analysis TGA and DTA show the expected thermo-decomposition behavior for both copper and lanthanum oxalates. This study reveals also the formation mechanism of the cuprate La2CuO4 from the used precursor. [ABSTRACT FROM AUTHOR]
- Published
- 2011
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32. Chemical compatibility of Sr-doped La2CuO4 cathode material with LSGM solid oxide electrolyte
- Author
-
Caronna, Tullio, Fontana, Francesca, Natali Sora, Isabella, Pelosato, Renato, and Viganò, Luca
- Subjects
- *
METALLIC oxides , *LANTHANUM compounds , *STRONTIUM , *CATHODES , *SOLID oxide fuel cells , *REACTIVITY (Chemistry) , *X-ray diffraction , *SELF-propagating high-temperature synthesis - Abstract
Abstract: The chemical reactivity of a novel cathode material for IT-SOFC, La2−xSrxCuO4−δ, with the oxide-ion conductor La0.83Sr0.17Ga0.83Mg0.17O3−w is investigated using XRD and ESEM/EDX techniques. La2−xSrxCuO4−δ samples (x=0.1 and 0.2) are prepared by citrate auto-combustion synthesis. The behaviour of mixtures of La2−xSrxCuO4−δ cathode material and La0.83Sr0.17Ga0.83Mg0.17O3−w (LSGM) electrolyte (1:1 weight ratio) annealed at 1000°C for 24–48h is studied. Peak broadening and shifting in the diffraction patterns are explained as diffusion of cations from one phase to the other; these findings are corroborated by the ESEM/EDX analysis. No diffraction peaks from reaction products are found. These results showed that the use of La2−xSrxCuO4−δ (x=0.1 and 0.2) cathode material in contact with LSGM electrolyte is not advantageous for SOFC application. [Copyright &y& Elsevier]
- Published
- 2010
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33. Synthesis and electrical properties of Ln2CuO4+ δ (Ln: Nd or La) mixed conductor sputter deposited coatings.
- Author
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Briois, P., Oliveira, J., Lapostolle, F., Perry, F., Billard, A., and Cavaleiro, A.
- Abstract
Nd
2 CuO4 and La2 CuO4 are potential candidates as cathode material for intermediate temperature-solid oxide fuel cells. Nd–Cu and La–Cu oxides were co-sputtered on rotating substrates from metallic La, Nd and Cu targets in the presence of a reactive argon–oxygen gas mixture. Structural and chemical features of these films have been determined by X-ray diffraction and energy-dispersive spectroscopy. Their electrical resistivity was measured using the four-point probe method. As-deposited Nd–Cu based coatings are amorphous and, after annealing, crystallise in K2 NiF4+ δ -type structure for Nd/Cu atomic ratio of 2, with more or less Nd2 O3 or CuO, depending on whether Nd or Cu is in excess, respectively. As-deposited La–Cu based coatings are also amorphous and crystallise in La2 CuO4 for La/Cu >2 or in LaCuO3± δ perovskite-type structure when Cu is in excess. The electrical measurements show a clear relation between resistivity and structure of the coatings. After annealing, crystallised neodymium-based coatings show higher resistivity than lanthanum-based ones. Finally, LaCuO3± δ exhibit higher resistivity than La2 CuO4 . [ABSTRACT FROM AUTHOR]- Published
- 2008
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34. Influence of the nature of the lanthanide element of Ln2CuO4 precursors on the catalytic activity obtained after activation in the CO + NO reaction
- Author
-
Peter, Stefan D., Garbowski, Édouard, Perrichon, Vincent, and Primet, Michel
- Subjects
- *
RARE earth metals , *NITRIC oxide , *COPPER , *HIGH temperatures , *PARTICLES - Abstract
Three lanthanide cuprates Ln2CuO4 (Ln = La, Pr and Nd) have been studied in the CO + NO reaction. Under reaction conditions, a reduction of the cuprate was observed, with formation of metallic copper, which constitutes the active species in the reaction. After stabilisation, the resulting activity is lower when La in La2CuO4 is replaced by Pr or Nd. This decrease in activity has been related to a different reducibility of the cuprates, as shown by TPR under H2. When La is substituted by Pr or Nd, a higher temperature of formation of the copper active sites should induce the growth of bigger copper particles, which could be at the origin of the observed difference in activity. To cite this article: S.D. Peter et al., C. R. Chimie 7 (2004). [Copyright &y& Elsevier]
- Published
- 2004
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- View/download PDF
35. Influence of Lattice Parameter Scaling on Local Electronic and Magnetic Properties in La2CuO4.
- Author
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Renold, S. and Meier, P.
- Abstract
A large amount of static and dynamic NMR experiments have been carried out to determine the spin properties in high temperature superconductors cuprates (HTSC). In the majority of cuprates the magnetic shift at the planar copper nucleus is independent of the temperature when the field is applied perpendicular to the CuO
2 planes and does not exhibit the expected reduction of the spin susceptibility in the superconducting state. This has been explained by a coincidental cancellation of on-site and transferred hyperfine fields at the copper nucleus, which would lead to a vanishing spin shift. To examine this explanation we determine the hyperfine fields by ab initio cluster calculations for La2 CuO4 within the framework of spin-polarized density functional theory. In particular we investigate the sensitivity of the hyperfine fields on the lattice constants. [ABSTRACT FROM AUTHOR]- Published
- 2003
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- View/download PDF
36. Stability and electrochemical performance of nanostructured La2CuO4þd cathodes
- Author
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J.M. Porras-Vázquez, J. Hurtado, Enrique R. Losilla, L. dos Santos-Gómez, and David Marrero-López
- Subjects
Materials science ,Fabrication ,Sintering ,02 engineering and technology ,Electrolyte ,Microelectrodos ,Solid oxide fuel cells ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,law.invention ,law ,Materials Chemistry ,Polarization (electrochemistry) ,Nanostructured electrodes ,Ce0.9Gd0.1O2-d ,Mechanical Engineering ,Metals and Alloys ,021001 nanoscience & nanotechnology ,Microstructure ,Pilas de combustible ,Cathode ,0104 chemical sciences ,Chemical engineering ,Mechanics of Materials ,Electrode ,La2CuO4 ,0210 nano-technology - Abstract
La2CuO4þd cathode layers are prepared by spray-pyrolysis deposition and their structural, microstructural and electrical properties are compared with those of submicrometric powders obtained from freeze-dried precursors. In order to improve the cathode performance, three different electrode architectures have been proposed: (i) powder cathodes obtained by conventional screen-printing and sintering, and cathodes deposited by spray-pyrolysis on: (ii) as-prepared electrolyte surfaces and (iii) porous electrolyte backbones. The cathode activity for the oxygen reduction reaction has been investigated as a function of the microstructure and the sintering temperature. The microstructural optimization of the cathodes and the low fabrication temperature minimize the instability problems between the electrolyte and the cathode materials, leading to polarization resistances as low as 0.14 U cm2 at 600 C. MINECO (Ministerio de Economía y Competitividad), MAT2016-77648-R y EC2014-53906-R
- Published
- 2019
37. Catalytic properties of La2CuO4 in the CO + NO reaction.
- Author
-
Peter, S.D., Garbowski, E., Guilhaume, N., Perrichon, V., and Primet, M.
- Abstract
La
2 CuO4 is an active catalyst for the reduction of NO by CO. Under reaction conditions, the catalyst exhibits an activation which results in a lowering of the light off temperature by 80°C. XRD, TEM and EDX analysis carried out after the catalytic test indicate that the mixed oxide has been reduced to form a La2 O3 , Cu binary system. It seems that metallic copper species are the most active sites in the CO + NO reaction. [ABSTRACT FROM AUTHOR]- Published
- 1998
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- View/download PDF
38. Reactivity of binary mixtures of Cu(II) oxalate and La(III) oxalate.
- Author
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Bapat, L., Natu, G., Bhide, M., and Kher, J.
- Abstract
Reactivity of binary mixtures of oxalates of Cu(II) and La(III) was studied by observing their thermal behaviours in decomposition using TG, DTA and XRD techniques to set the temperature conditions for preparations of various composites of oxides of Cu(II) and La(III). In the thermal behaviour it was found that the decomposition of Cu(II) oxalate is not affected while that of La(III) oxalate is drastically affected in the case of all the mixtures. The decomposition temperature at which La(III) oxide is formed is lowered by 250 K in the case of all the mixtures while the complete decomposition occurred at 723 K only in the case of mixtures containing excess Cu(II) oxalate. At 823 K La
2 CuO4 phase is developed in all the mixtures while α-La and Cu2 La phases are also detected in mixtures containing excess Cu(II) oxalate. Therefore, the temperature 823 K was found to be suitable to prepare various composites viz. La2 CuO4 , La2 CuO4 ·La2 O3 and La2 CuO4 ·CuO to study their electrical properties. [ABSTRACT FROM AUTHOR]- Published
- 1997
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- View/download PDF
39. Spatial modulation of low-frequency spin fluctuations in hole-doped La2CuO4.
- Author
-
Yamada, K., Lee, C., Wada, J., Kurahashi, K., Kimura, H., Endoh, Y., Hosoya, S., Shirane, G., Birgeneau, R., and Kastner, M.
- Abstract
Systematic neutron scattering measurements have been performed on the Sr-doped La
{2- x} Srx CuO4 to study the doping dependence of spatially modulated dynamical spin correlations or so-called incommensurate spin fluctuations. The modulated spin correlations appear beyond x ≈ 0.05 which is close to the lower boundary of the superconducting phase. First evidence was observed for the linear relation between the degree of spatial modulation or the incommensurability Σ(x) and the maximum Tc at x. We present a universal curve for Σ(x) by adding data from other La2 CuO2 systems such as oxygen-doped superconductors, oxygen-reduced or Zn-substituted nonsuperconductors, and La1.6-x Nd0.4 Srx CuO4 . [ABSTRACT FROM AUTHOR]- Published
- 1997
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40. Stripe correlation of tilts and superconductivity in La2CuO4+Σ.
- Author
-
Wochner, P., Xiong, X., and Moss, S.
- Abstract
In single crystal La
2 CuO4+Σ ,Σ ≈ 0.015, c-axis interstitial oxygen ordering (staging) in the oxygen-rich phase of the phase-separated sample was observed through satellite peaks in the neutron scattering which first appear at 250 K. If the sample is cooled through the temperature region around 210 K over a period of several hours, these satellite peaks show splitting in the a*-direction. This first-order phase transition involves a periodic one-dimensional modulation of the in-plane order. Microscopic modeling leads to a picture where the excess oxygen, and therefore also the doped holes, order in stripes along the a-direction in addition to staging along the c-direction. This ordering in stripes can be regarded as a continuation of the phase separation but now on a local scale, leading to a local increase in oxygen and hole density. This increase can account for the increase of the superconducting Tc of 2.5 K observed in our sample and also for many previously reported annealing experiments. [ABSTRACT FROM AUTHOR]- Published
- 1997
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- View/download PDF
41. Photocatalytic generation of hydrogen under visible light on La2CuO4
- Author
-
LAHMAR, H and TRARI, M
- Published
- 2015
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- View/download PDF
42. Rectifying properties of the La2CuO4/Nb-0.7wt%-doped SrTiO3 heterojunction
- Author
-
Fang, Jin, Cui, Yimin, Zhang, Yong, and Qiu, Ming
- Subjects
- *
THIN films , *CRYSTALS , *HETEROSTRUCTURES , *SOLID state electronics - Abstract
Abstract: Using a two-step growth technique, simple oxide heterostructures have been fabricated by pulsed laser depositing epitaxial La2CuO4 (LCO) thin films on Nb-0.7wt%-doped SrTiO3 (NSTO) substrates. The junctions show good rectifying behavior at all measuring temperatures and an obvious temperature dependence of current–voltage (I–V) properties in the range of 25–300K, which are discussed in relation to the p–n model. [Copyright &y& Elsevier]
- Published
- 2007
- Full Text
- View/download PDF
43. La2CuO4-decorated ZnO nanoparticles with improved photocatalytic activity for malachite green degradation.
- Author
-
Yulizar, Yoki, Apriandanu, Dewangga Oky Bagus, and Ashna, Raden Iqrafia
- Subjects
- *
MALACHITE green , *NANOPARTICLES , *ELECTRON-hole recombination , *NANOCOMPOSITE materials - Abstract
• La 2 CuO 4 -decorated ZnO was designed by in situ nanoparticle fabrication using SLE. • ZnO modification with La 2 CuO 4 can improve its photocatalytic activity. • Various characterization techniques were performed. • ZnO-La 2 CuO 4 exhibit excellent photocatalytic activity compared to ZnO and La 2 CuO 4. In this research, La 2 CuO 4 -decorated ZnO was designed by in situ nanoparticle fabrication using Strobilanthes crispus (B.) leaves extract (SLE) for the first time. To investigate the properties, La 2 CuO 4 -decorated ZnO were characterized by various characterization techniques. By a modification with La 2 CuO 4 , ZnO possesses the improved photocatalytic activity for malachite green degradation under visible-light illumination. ZnO-La 2 CuO 4 nanocomposites exhibit high photocatalytic activity compared to ZnO and La 2 CuO 4. The improved photocatalytic activity can be ascribed to the effect of the decreased bandgap value of the nanocomposite structure due to the low recombination of photogenerated electron-hole pairs. Furthermore, ZnO-La 2 CuO 4 shows good stability after three-run of photocatalysis experiment. The present research offers an eco-friendly and cost-effective method as an alternative for ZnO-La 2 CuO 4 nanocomposites fabrication with excellent photodegradation performance. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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44. Effect of Thermal Stresses Formed during Air Annealing of Amorphous Lanthanum Cuprate Thin Films Deposited on Silicon Substrate.
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Tranvouez, Nolwenn, Steyer, Philippe, Malchère, Annie, Boulet, Pascal, Capon, Fabien, Bauer, Jean-Philippe, and Pierson, Jean-François
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THIN films ,SILICON films ,THERMAL stresses ,MAGNETRON sputtering ,THERMAL expansion ,LANTHANUM ,DELAMINATION of composite materials - Abstract
Amorphous thin films of La–Cu–O deposited by magnetron sputtering have been annealed at different temperatures and in situ analyzed by X-ray diffraction. These experiments were useful to determine the crystallization temperature and to follow the crystallization process of the film. The in situ annealing X-ray diffraction analyses have been also used to determine the thermal expansion coefficient of La
2 CuO4 thin film. The estimated value is close to that obtained for a commercial powder. The thermal expansion coefficient value with additional environmental scanning electron microscopy observations explains the delamination origin that occurs during the annealing before the crystallization step. The buckling and delamination of the film observed is caused by the thermal expansion coefficient mismatch of the film and the substrate. During the heating step, the mismatch generates compressive stress at the film/substrate interface, causing the film to lift off and crack in the typical way. [ABSTRACT FROM AUTHOR]- Published
- 2020
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45. Electrochemical insights into layered La2CuO4 perovskite: Active ionic copper for selective CO2 electroreduction at low overpotential.
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Singh, Rana Pratap, Arora, Payal, Nellaiappan, Subramanian, Shivakumara, C., Irusta, Silvia, Paliwal, Manas, and Sharma, Sudhanshu
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- *
ELECTROLYTIC reduction , *ELECTROCATALYSIS , *CALCINATION (Heat treatment) , *PEROVSKITE , *LATTICE constants , *RIETVELD refinement , *CYCLIC voltammetry , *COPPER - Abstract
La 2 CuO 4 , a layered perovskites oxide was synthesized using solution combustion method at different calcination temperatures. XRD characterization and Rietveld refinement analysis confirms the pure phase of the synthesized material. The effect of calcination causes shrinking in the lattice parameters affirm the change in the oxygen stoichiometry. Four Probe (Van der Pauw's) and CP-AFM analysis were carried out to understand the influences of calcination temperature on electrical conductivity. Electrochemical investigations on La 2 CuO 4 were performed at various negative potential ranges using cyclic voltammetry (CV) to identify the redox active centre. Thermodynamic calculations are further carried out to validate the electrochemical results in different mediums. Selective electrocatalytic conversion of CO 2 to C 2 -hydrocarbon (C 2 H 4) with FE% of 40.3% which is 10 times higher than CH 4 (FE% = 4.1%) emphasized the in-situ formation of Cu 2 O from the redox active centre present in La 2 CuO 4. Hydrocarbons are generated at a very low overvoltage (−0.4 V RHE) in comparison to literature. XPS analysis indeed confirms the presence of Cu+ species i.e., in-situ generated Cu 2 O, on La 2 CuO 4 after CV and CO 2 electrocatalysis. Image 108061 • In the present study, we have explored the electrochemical behavior of redox active centre 'Cu2+' in a highly crystalline layered La 2 CuO 4 perovskite. • During electrochemical reduction, La 2 CuO 4 breaks into La 2 O 3 and Cu 2 O. This Cu 2 O further undergo reduction and forms Cu metal which is a reversible reaction. • Thermodynamic calculations aided in understanding the electrochemical in-situ formation of Cu 2 O. • Selective electrocatalytic reduction of CO 2 to C 2 H 4 (10 times higher than CH 4), at −0.4 V RHE, very low overpotential, emphasis the typical behaviour of Cu 2 O. • XPS analysis confirms the presence of Cu+ species (i.e., Cu 2 O) after electrochemical treatment of La 2 CuO 4 and retained after selective CO 2 electrocatalysis. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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46. Effects beyond the -model in the low-energy physics of cuprates
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Drechsler, S.-L., Málek, J., Eschrig, H., Knupfer, M., and Rosner, H.
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- *
HUBBARD model , *ENERGY-band theory of solids , *LOW energy electron diffraction , *NUCLEAR excitation - Abstract
Abstract: The role of orbitals beyond the Cu 3d O 2p set employed in the widely used extended Hubbard model is considered with respect to low-energy charge excitations in cuprates. We focus on the description of the EELS and optical conductivity data of Sr2CuO3 and Sr2CuO2Cl2 with respect to O states. Consequences for the orbital character of doped holes are discussed. The achieved novel description of the EELS data in transverse chain response is robust with respect to the addition of Cu and 4s orbitals. [Copyright &y& Elsevier]
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- 2005
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47. Selective conversion of glycerol to hydroxyacetone in gas phase over La2CuO4 catalyst
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Mauricio Velasquez, Alexander Santamaría, Catherine Batiot-Dupeyrat, Universidad de Antioquia = University of Antioquia [Medellín, Colombia], Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), and Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Poitiers-Institut de Chimie du CNRS (INC)
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Glycerol ,Thermogravimetric analysis ,Inorganic chemistry ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Catalysis ,Metal ,chemistry.chemical_compound ,medicine ,Dehydration ,General Environmental Science ,Hydroxyacetone ,Process Chemistry and Technology ,[CHIM.CATA]Chemical Sciences/Catalysis ,Atmospheric temperature range ,021001 nanoscience & nanotechnology ,medicine.disease ,Copper ,0104 chemical sciences ,chemistry ,visual_art ,visual_art.visual_art_medium ,La2CuO4 ,0210 nano-technology - Abstract
International audience; The gas phase dehydration of glycerol to hydroxyacetone was investigated over La2CuO4 catalyst under inert conditions. The reaction was performed in the temperature range of 260-400 degrees C. At low temperature (260 and 280 degrees C) high yields of hydroxyacetone can be achieved: 76% while at higher temperatures carbon deposition occurred. We showed that the structure of the La2CuO4 catalyst was modified during time on stream: Cu2+ was partially reduced into Cu1+ even at 260 degrees C. The formation of Cu2O was revealed by XRD and XPS analysis confirmed that both Cu2+ and Cu1+ are present at the surface of the catalyst. After reduction of La2CuO4 into Cu-0/La2O3, low catalytic activity was observed proving that metallic copper is not the required species to perform the dehydration of glycerol into hydroxyacetone under our experimental conditions. TGA analysis revealed that only small amount of carbon deposition occurred during time on stream at 260 degrees C, no catalytic deactivation being observed during 20 h of reaction.
- Published
- 2015
48. La2CuO4 sensing electrode configuration influence on sensitivity and selectivity for a multifunctional potentiometric gas sensor
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Bryan M. Blackburn, Eric D. Wachsman, Enrico Traversa, Eric R. Macam, Briggs White, and Elisabetta Di Bartolomeo
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Auxiliary electrode ,Chemistry ,Settore ING-IND/22 - Scienza e Tecnologia dei Materiali ,Potentiometric titration ,La2CuO4, NOx, CO ,Metals and Alloys ,Analytical chemistry ,NOx ,Repeatability ,Electrolyte ,Condensed Matter Physics ,Electrical contacts ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,CO ,Planar ,Electrode ,Materials Chemistry ,Potentiometric sensor ,La2CuO4 ,Electrical and Electronic Engineering ,Instrumentation - Abstract
a b s t r a c t The effects of electrical contact configuration for La2CuO4 sensing electrodes for a planar-based poten- tiometric gas sensor were studied in order to further quantify the effects of processing on sensor performance. Five configurations of La2CuO4 were used for the sensing electrode. The La2CuO4 sens- ing electrode was screen printed opposite a Pt counter electrode on a tape cast YSZ electrolyte. Three sensors were prepared for each configuration to test repeatability. Each sensor was tested at tempera- tures from 400 to 700 ◦C at various concentrations of NO2, NO, and CO in an environment of 3% O2 with a balance of N2. Results show that these sensors exhibit suitable sensitivity to all the gases tested. More importantly, it was shown that the sensitivity, selectivity/cross-sensitivity, and repeatability of these sensors are dependent on the sensing electrode configuration.
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- 2011
49. Crystal growth and physico-chemical characterizations of the superconductor solid solutions La2-xSrxCuO4 et La1,6-xNd0,4SrxCuO4
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Denis, Sylvain, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université Paris Sud - Paris XI, and Patrick Berthet
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Superconductivity ,Technique de la fusion de la zone solvante ,Caractérisations physico-chimiques ,Cristallogenèse ,Travelling solvent floating zone ,Physico-chemical characterizations ,Crystal growth ,La2CuO4 ,[CHIM.OTHE]Chemical Sciences/Other ,Supraconductivité - Abstract
High critical temperature superconductivity discovery in cuprates superconductors in 1986 revolutionized this sector and questioned the BCS theory. In spite of great improvement in critical temperatures, no theory fully explains the properties of these materials.The critical temperature evolution according to strontium’s content in La2-xSrxCuO4 and La1,6 xNd0,4SrxCuO4 superconductor solid solutions show a superconductive dome for 0,05 < x < 0,30. However, around x = 0,125, there is a magnetic anomaly where the critical temperature decreased. With the help of more efficient technologies, new physical analysis might help to give a better interpretation of the superconductivity in the cuprates materials.Therefore single crystals of great quality are needed. The travelling-solvent floating-zone method is particularly compatible with non-congruent fusion materials as cuprates.First, a preliminary study on polycrystalline samples was conducted and gave interesting information about structure and physical properties. X-rays powder diffraction experiments were used to analyze the crystalline structures and the cell parameters of these materials. The La2-xSrxCuO4 solid solutions crystallize in the orthorhombic Bmab system if x < 0,11, and in the tetragonal I4/mmm system if x > 0,11.With the substitution of Lanthanum ions by Neodymium ions, the orthorhombic phase is stabilized and the transition occurs only for x near 0,19. The critical temperatures of these compounds are extracted from the magnetic properties analysis, obtained by a SQUID magnetometer. These properties are more complicated for the La1,6 xNd0,4SrxCuO4 solid solutions because of the paramagnetic nature of Nd3+ ions.In this work, the crystals are synthesized in an optical furnace with small growth rates (1 mm.h-1). For the selected compositions of La1,875Sr0,125CuO4 and La1,475Nd0,4Sr0,125CuO4, the solvent rod must be optimal. Crystalline quality of the crystals is checked by polarized light microscopy and by the LAUE method. Elemental analysis by electron probe micro analysis and the results of the cell parameters and the critical temperatures, compared with those obtained from the polycrystalline materials are used for the composition determination of these crystals.; La découverte de la supraconductivité à haute température dans les cuprates supraconducteurs en 1986 a révolutionné le secteur et remis en cause la théorie conventionnelle (BCS) de la supraconductivité. Malgré des avancées importantes dans la course aux plus hautes températures critiques, à ce jour, aucune théorie ne fournit une interprétation satisfaisante des propriétés de ces matériaux.L’évolution de la température critique en fonction du taux de strontium dans les solutions solides supraconductrices La2-xSrxCuO4 et La1,6 xNd0,4SrxCuO4 forme un dôme supraconducteur pour 0,05 < x < 0,30. Cependant ce dôme montre une anomalie autour de la teneur x = 0,125, où la température critique est abaissée. Grâce aux technologies de plus en plus performantes, de nouvelles analyses physiques pourraient aider à comprendre la supraconductivité dans les cuprates.Pour cela, des monocristaux d’excellente qualité sont nécessaires. La technique de croissance cristalline par la méthode de fusion de la zone solvante est très adaptée à la synthèse de ce type de matériau à fusion non congruente.Une étude préliminaire sur des céramiques a permis de collecter de nombreuses informations. Une analyse par diffraction des rayons X permet de connaitre l’évolution des structures cristallines et des paramètres de mailles en fonction de la teneur en strontium. Les solutions solides La2-xSrxCuO4 cristallisent dans le système orthorhombique Bmab lorsque x < 0,11 et dans le système quadratique I4/mmm pour x > 0,11. En substituant une partie des ions lanthanes par des ions néodymes, la phase orthorhombique est stabilisée et la transition intervient quand x est proche de 0,19. Les températures critiques de ces composés sont déterminées par l’analyse des propriétés magnétiques réalisées à l’aide d’un magnétomètre à SQUID. Ces dernières sont plus complexes pour les solutions solides La1,6 xNd0,4SrxCuO4 en raison du caractère paramagnétiques des ions Nd3+.Les solides cristallisés présentés dans ce travail ont été élaborés dans un four à concentration de rayonnement avec des vitesses de croissance très lentes (1 mm.h-1). Pour atteindre les compositions visées La1,875Sr0,125CuO4 et La1,475Nd0,4Sr0,125CuO4, il est indispensable d’identifier une composition optimale de la pastille solvante. La qualité cristalline des solides cristallisés est observée par l’intermédiaire d’un microscope à lumière polarisée et par la diffraction des rayons X par la méthode de LAUE. La détermination des paramètres de maille, des températures critiques, des analyses élémentaires par microsonde, couplés aux résultats obtenus sur les céramiques permettent d’obtenir la teneur en cation de ces cristaux.
- Published
- 2014
50. Synthesis and electrical properties of Ln2CuO4+ δ (Ln: Nd or La) mixed conductor sputter deposited coatings
- Author
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Briois, P., Oliveira, J. C., Lapostolle, F., Perry, F., Billard, A., and Cavaleiro, A.
- Published
- 2008
- Full Text
- View/download PDF
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