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Nanofeather ruthenium nitride electrodes for electrochemical capacitors. NATURE MATERIALS 2024; 23:670-679. [PMID: 38413809 DOI: 10.1038/s41563-024-01816-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 01/19/2024] [Indexed: 02/29/2024]
Abstract
Fast charging is a critical concern for the next generation of electrochemical energy storage devices, driving extensive research on new electrode materials for electrochemical capacitors and micro-supercapacitors. Here we introduce a significant advance in producing thick ruthenium nitride pseudocapacitive films fabricated using a sputter deposition method. These films deliver over 0.8 F cm-2 (~500 F cm-3) with a time constant below 6 s. By utilizing an original electrochemical oxidation process, the volumetric capacitance doubles (1,200 F cm-3) without sacrificing cycling stability. This enables an extended operating potential window up to 0.85 V versus Hg/HgO, resulting in a boost to 3.2 F cm-2 (3,200 F cm-3). Operando X-ray absorption spectroscopy and transmission electron microscopy analyses reveal novel insights into the electrochemical oxidation process. The charge storage mechanism takes advantage of the high electrical conductivity and the morphology of cubic ruthenium nitride and Ru phases in the feather-like core, leading to high electrical conductivity in combination with high capacity. Accordingly, we have developed an analysis that relates capacity to time constant as a means of identifying materials capable of retaining high capacity at high charge/discharge rates.
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CoVO 3 High-Pressure Polymorphs: To Order or Not to Order? ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2307766. [PMID: 38103011 PMCID: PMC10916632 DOI: 10.1002/advs.202307766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/21/2023] [Indexed: 12/17/2023]
Abstract
Materials properties are determined by their compositions and structures. In ABO3 oxides different cation orderings lead to mainly perovskite- or corundum like derivatives with exciting physical properties. Sometimes, a material can be stabilized in more than one structural modification, providing a unique opportunity to explore structure-properties relationship. Here, CoVO3 obtained in both ilmenite-(CoVO3 -I) and LiNbO3 -type (CoVO3 -II) polymorphs at moderate (8-12 GPa) and high pressures (22 GPa), respectively are presented. Their distinctive cation distributions affect drastically the magnetic properties as CoVO3 -II shows a cluster-glass behavior while CoVO3 -I hosts a honeycomb zigzag magnetic structure in the cobalt network. First principles calculations show that the influence of vanadium is crucial for CoVO3 -I, although it is previously considered as non-magnetic in a dimerized spin-singlet state. Contrarily, CoVO3 -II shows two independent interpenetrating antiferromagnetic Co- and ferromagnetic V-hcp sublattices, which intrinsically frustrate any possible magnetic order. CoVO3 -II is also remarkable as the first oxide crystallizing with the LiNbO3 -type structure where both metals contain free d electrons. CoVO3 polymorphs pinpoint therefore as well to a much broader phase field of high-pressure A-site Cobaltites.
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Degradation mechanisms of organic compounds in molten hydroxide salts: a radical reaction yielding H 2 and graphite. RSC Adv 2023; 13:19955-19964. [PMID: 37409032 PMCID: PMC10318416 DOI: 10.1039/d3ra02537c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 06/07/2023] [Indexed: 07/07/2023] Open
Abstract
Molten salts are used in various waste treatments, such as recycling, recovery or making inert. Here, we present a study of the degradation mechanisms of organic compounds in molten hydroxide salts. Molten salt oxidation (MSO) using carbonates, hydroxides and chlorides is known for the treatment of hazardous waste, organic material or metal recovery. This process is described as an oxidation reaction due to the consumption of O2 and formation of H2O and CO2. We have treated various organic products, carboxylic acids, polyethylene and neoprene with molten hydroxides at 400 °C. However, the reaction products obtained in these salts, especially carbon graphite and H2 without CO2 emission, challenges the previous mechanisms described for the MSO process. Combining several analyses of the solid residues and the gas produced during the reaction of organic compounds in molten hydroxides (NaOH-KOH), we demonstrate that these mechanisms are radical-based instead of oxidative. We also show that the obtained end products are highly recoverable graphite and H2, which opens a new way of recycling plastic residues.
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Layered monophosphate tungsten bronzes [Ba(PO4)2]WmO3m‐3: 2D‐metals with locked charge‐density‐wave instabilities. Angew Chem Int Ed Engl 2023. [DOI: 10.1002/ange.202302049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/09/2023]
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Layered monophosphate tungsten bronzes [Ba(PO4)2]WmO3m-3: 2D-metals with locked charge-density-wave instabilities. Angew Chem Int Ed Engl 2023:e202302049. [PMID: 37021737 DOI: 10.1002/anie.202302049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 04/04/2023] [Accepted: 04/06/2023] [Indexed: 04/07/2023]
Abstract
Phosphate tungsten and molybenum bronzes represent an outstanding class of materials displaying textbook examples of charge-density-wave (CDW) physics among other fundamental properties. Here we report on the existence of a novel structural branch with the general formula [Ba(PO4)2][W3O3-m] (m = 3, 4 and 5) denominated 'layered monophosphate tungsten bronzes' (L-MPTB). It results from thick [Ba(PO4)2]4- spacer layers disrupting the cationic metal oxide 2D-units and enforcing an overall trigonal structure. Their symmetries are preserved down to 1.8 K and the compounds show metallic behaviour with no clear anomaly as a function of temperature. However, their electronic structure displays the characteristic Fermi surface of previous bronzes derived from 5d-W states with hidden nesting properties. By analogy with previous bronzes, such a Fermi surface should result into CDW-order. Evidence of CDW-order was only indirectly observed in the low-temperature specific heat, giving an exotic context at the crossover between stable-2D metals and CDW-order.
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Influence of ion implantation on the charge storage mechanism of vanadium nitride pseudocapacitive thin films. Electrochem commun 2021. [DOI: 10.1016/j.elecom.2021.107016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Complex magnetism in Ni 3TeO 6-type Co 3TeO 6 and high-pressure polymorphs of Mn 3-xCo xTeO 6 solid solutions. Chem Commun (Camb) 2021; 57:2511-2514. [PMID: 33538279 DOI: 10.1039/d0cc07487j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
New Ni3TeO6-type (NTO) and double perovskite (DPv) polymorphs of Co3TeO6 are synthesised at pressures of 15 GPa. A complex elliptic helical magnetic order is observed in the NTO polymorph (TN1 = 58 K) that reorientates (42 K) and further splits (TN2 = 23.5 K) creating a coexisting helix. Increasing Co content within the Mn3-xCoxTeO6 system changes the dominant DPv phase to NTO structural type and drastically modifies the magnetic behaviour. DPv Co3TeO6 is the first A-site double cobaltite.
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High pressure exploration in the Li-Ln-V-O system. Dalton Trans 2020; 49:13663-13670. [PMID: 32986057 DOI: 10.1039/d0dt02721a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Using in situ high pressure Raman spectroscopy, two structural changes were observed in a sample of the composition LiLa5O5(VO4)2. Taking this into account and by combining different conditions, three new compounds were further obtained from high pressure-high temperature synthesis. Their crystal structure description was done using the antiphase approach, which implies the presence of oxygen-centered [OLn4] building units, where Ln is La for (1) β-LiLa5O5(VO4)2 and (2) β-LiLa2O2(VO4) or Nd for (3) LiNd5O5(VO4)2 compounds. (1) crystallizes in the triclinic space group P1[combining macron] with unit cell parameters of a = 5.8167(15) Å, b = 12.2954(28) Å, c = 18.7221(69) Å, α = 102.03(2)°, β = 98.76(2)°, and γ = 103.54(2)°; a 3D structure was deduced from the ambient pressure polymorph. (2) also crystallizes in P1[combining macron] with a = 5.8144(7) Å, b = 5.8167(7) Å, c = 8.5272(1) Å, α = 98.184(7)°, β = 100.662(7)° and γ = 92.579(7)°. It shows a 2D structure with [La2O2]2+ layers surrounded by [LiO4] and [VO4] tetrahedra sharing corners and edges. (3) exhibits a 3D architecture isotypic with AP-LiLa5O5(VO4)2. The crucial role of high pressure in such types of synthesis and materials is also discussed.
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Pure and RE 3+-Doped La 7O 6(VO 4) 3 (RE = Eu, Sm): Polymorphism Stability and Luminescence Properties of a New Oxyvanadate Matrix. Inorg Chem 2020; 59:5929-5938. [PMID: 32285666 DOI: 10.1021/acs.inorgchem.9b03689] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Two polytypes of the new oxyvanadate matrix La7O6(VO4)3 were identified and deeply characterized. The crystal structure of the α-polytype was solved using a combination of precession electron diffraction and powder X-ray diffraction (XRD) techniques. It crystallizes in a monoclinic unit cell with space group P21, a = 13.0148(3) Å, b = 19.1566(5) Å, c = 7.0764(17) Å, and β = 99.87(1)°. Its structure is built upon [La7O6]9+ polycationic units at the origin of a porous 3D network, evidencing rectangular channels filled by isolated VO4 tetrahedra. An in situ high-temperature XRD study highlights a number of complex phase transitions assorted with the existence of a β-polytype also refined in a monoclinic unit cell, space group P21/n, a = 13.0713(4) Å, b = 18.1835(6) Å, c = 7.1382(2) Å, and β = 97.31(1)°. Thus, during the transitions, while the polycationic networks are almost identical, the vanadate's geometry is largely modified. The use of Eu3+ and Sm3+ at different concentrations in the host lattice is possible using solid-state techniques. The photoluminescence (PL), PL excitation (PLE) spectra, and luminescence decay times were recorded and discussed. The phosphors present an emission light, being bright and reddish orange after excitation under UV. This is mainly due to the V-O band and f-f transitions. Whatever the studied polytype, the final luminescence properties are retained during the heating/cooling process.
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Oxysulfide Ba 5(VO 2S 2) 2(S 2) 2 Combining Disulfide Channels and Mixed-Anion Tetrahedra and Its Third-Harmonic-Generation Properties. Inorg Chem 2020; 59:5907-5917. [PMID: 32319754 DOI: 10.1021/acs.inorgchem.9b03674] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mixed-anion compounds are among the most promising systems to design functional materials with enhanced properties. In particular, heteroleptic environments around transition metals allow tuning of the polarity or band-gap engineering for instance. We present the original oxysulfide Ba5(VO2S2)2(S2)2, the fifth member in the quaternary system Ba-V-S-O. It exhibits the mixed-anion building units V5+O2S2 and isolated disulfide pairs (S2)2-. The structure is solved by combining single-crystal and powder X-ray diffraction and transmission electron microscopy. First-principles calculations were combined in order to highlight the anion roles. In particular, our density functional theory study shows that the 3p states of the disulfide pairs dictate the band gap. In this study, we point out anionic tools for band-gap engineering that can be useful for the design of phases for numerous applications. Finally, third harmonic generation (THG) was measured and compared to the large THG observed for Cu2O, which reveals the potential for nonlinear-optical properties that should be further investigated.
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Abstract
Here we show the complexity in the BaM2(PO4)2 (M = Mn, Fe, Co) phase diagram. The original structures are discussed in terms of structural stability by comparison between the systems and by analogy to the number of transitions in these phase diagrams.
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Nickel Exsolution‐Driven Phase Transformation from an n=2 to an n=1 Ruddlesden‐Popper Manganite for Methane Steam Reforming Reaction in SOFC Conditions. ChemCatChem 2019. [DOI: 10.1002/cctc.201901002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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The hidden story in BaNiO 3 to BaNiO 2 transformation: adaptive structural series and NiO exsolution. Chem Commun (Camb) 2019; 55:3717-3720. [PMID: 30869087 DOI: 10.1039/c8cc09610d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
BaNiO3 crystal to BaNiO2 crystal transformation is reported. Contrary to an intuitive topochemical reduction, a two step reaction was observed. In the first step, NiO exsolution occurs and intermediate Ba1+xNiO3 phases were obtained and isolated. A composite approach was used to solve the novel structure for x ∼ 1/6 with charge ordered Ni2+ and Ni4+. We argue that this NiO exsolution is responsible for the increased oxygen enhanced reactivity recently reported. Upon re-oxidation, oxygen-deficient mixed valent BaNi3/4+O3-x are obtained such that the full redox cycle is irreversible and goes through a diversity of structural and nickel valence adaptative oxides.
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Microstructure and local electrical behavior in [(Nd 2Ti 2O 7) 4/(SrTiO 3) n ] 10 ( n = 4-8) superlattices. RSC Adv 2018; 8:11262-11271. [PMID: 35542786 PMCID: PMC9078952 DOI: 10.1039/c8ra00824h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 03/08/2018] [Indexed: 11/21/2022] Open
Abstract
Artificial [(Nd2Ti2O7)4/(SrTiO3)n]10 superlattices (n = 4 and 8) were successfully epitaxially grown on SrTiO3 substrates by pulsed laser deposition using the in situ high energy electron diffraction reflection diagnostic. The crystallographic relationships between Nd2Ti2O7 (NTO) and SrTiO3 (STO) (layers and substrate) were: [100]NTO//[001]STO, [010]NTO//[1̄10]STO, and (00l)NTO//(110)STO. Nanoscale current variation was detected on both superlattices, with the (NTO4/STO4)10 heterostructure showing a higher density. The (NTO4/STO4)10 sample did not show a piezoelectric response when measured by piezo-force microscopy (PFM), while ambiguous piezoactivity was observed on the (NTO4/STO8)10 superlattice. Scanning transmission electron microscopy energy dispersive spectroscopy analysis showed the diffusion of Nd3+ cations on Sr2+ sites in SrTiO3 structure into the multilayers, which was more pronounced when the value of n was lower. These particular nanoscale electrical behaviors, evidenced by electrical conducting channels and misleading PFM signals, were mainly attributed to the presence of oxygen vacancies in the SrTiO3 layers at higher concentrations near the interface and to the mixed valence state of the titanium (Ti3+/Ti4+). This work showed the strong influence of interface structure on nanoscale electrical phenomena in complex oxide superlattices. Artificial [(Nd2Ti2O7)4/(SrTiO3)n]10 superlattices were epitaxially grown. Local conductivity and misleading PFM signals were mainly attributed to the oxygen vacancies in the SrTiO3 layers and to the mixed valence state of the titanium.![]()
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From anion-centered tetrahedra to modular chemistry of Bi/La oxysalts. Acta Crystallogr A Found Adv 2017. [DOI: 10.1107/s2053273317094906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Comprehensive Study of Oxygen Storage in YbFe 2O 4+x (x ≤ 0.5): Unprecedented Coexistence of FeO n Polyhedra in One Single Phase. J Am Chem Soc 2017; 139:17031-17043. [PMID: 29094941 DOI: 10.1021/jacs.7b06409] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The multiferroic LuFe2.5+2O4 was recently proposed as a promising material for oxygen storage due to its easy reversible oxidation into LuFe3+2O4.5. We have investigated the similar scenario in YbFe2O4+x, leading to a slightly greater oxygen storage (OSC) capacity of 1434 μmol O/g. For the first time, the structural model of LnFe2O4.5 was fully understood by high-resolution microscopy images, and synchrotron and neutron diffraction experiments, as well as maximum entropy method. The oxygen uptake promotes a reconstructive shearing of the [YbO2] sub-units controlled by the adaptive Ln/Fe oxygen coordination and the Fe2/3+ redox. After oxidation, the rearrangement of the Fe coordination polyhedra is unique such that all available FeOn units (n = 6, 5, 4 in octahedra, square pyramids, trigonal bipyramids, tetrahedra) were identified in modulated rows growing in plane. This complex pseudo-ordering gives rise to short-range antiferromagnetic correlation within an insulating state.
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Original positively charged nanoflakes by liquid exfoliation of layered oxybromide cobaltites. CrystEngComm 2017. [DOI: 10.1039/c6ce02248k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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A Performant Dry Reforming Catalytic System Elaborated from the Reductive Decomposition of BaNi 2V 2O 8. ChemistrySelect 2016. [DOI: 10.1002/slct.201601109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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On the Use of Dynamical Diffraction Theory To Refine Crystal Structure from Electron Diffraction Data: Application to KLa5O5(VO4)2, a Material with Promising Luminescent Properties. Inorg Chem 2016; 55:2252-60. [DOI: 10.1021/acs.inorgchem.5b02663] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
The 2D-Ising ferromagnetic phase BaFe(2+)2(PO4)2 shows exsolution of up to one-third of its iron content (giving BaFe(3+)1.33(PO4)2) under mild oxidation conditions, leading to nanosized Fe2O3 exsolved clusters. Here we have prepared BaFe(2-y)M(y)(PO4)2 (M = Co(2+), Ni(2+); y = 0, 0.5, 1, 1.5) solid solutions to investigate the feasibility and selectivity of metal exsolution in these mixed metallic systems. For all the compounds, after 600 °C thermal treatment in air, a complete oxidation of Fe(2+) to Fe(3+) leaves stable M(2+) ions, as verified by (57)Fe Mössbauer spectroscopy, TGA, TEM, microprobe, and XANES. The size of the nanometric α-Fe2O3 clusters coating the main phase strongly depends on the yM metal concentration. For M-rich phases the iron diffusion is hampered so that a significant fraction of superparamagnetic α-Fe2O3 particles (100% for BaFe(0.5-x)Co(1.5)(PO4)2) was detected even at 78 K. Although Ni(2+) and Co(2+) ions tend to block Fe diffusion, the crystal structure of BaFe(0.67)Co1(PO4)2 demonstrates a fully ordered rearrangement of Fe(3+) and Co(2+) ions after Fe exsolution. The magnetic behaviors of the Fe-depleted materials are mostly dominated by antiferromagnetic exchange, while Co(2+)-rich compounds show metamagnetic transitions reminiscent of the BaCo2(PO4)2 soft helicoidal magnet.
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Abstract
Single crystals of a new oxide, La3Fe(MoO4)6, were grown from fluxes of oxide precursors, and a polycrystalline sample was also prepared by a standard solid state reaction. La3Fe(MoO4)6 crystallizes in the orthorhombic space group Pbca with unit cell parameters a = 19.3164(11), b = 10.4143(5) and c = 22.0594(12) Å. This crystal structure exhibits a singular architectural type built on infinite chains of Fe(MoO4)4, each of them being surrounded by two isolated MoO4 tetrahedra and three isolated La(3+) cations. Fe(3+) ions in La3Fe(MoO4)6 are antiferromagnetically ordered below TN = 6.6 K in chains and between chains, as refined from neutron diffraction data. Further the redox stability of this compound - pure powder - was checked using temperature-programmed X-ray diffraction under a controlled atmosphere; under air, we observed a reversible phase transition above 523 K. The same phenomenon was observed under a reductive atmosphere, followed by a destruction of the as-formed phase above 923 K owing to iron III to II reduction. Reactivity of ethanol was then evaluated to get insights into the redox properties of the material under working conditions. After 4 hours of reaction at 648 K, the ethanol conversion was 97% with a selectivity to acetaldehyde of ∼60%, the other products being formaldehyde (∼10%) and CO2 (∼30%), underlining a better acetaldehyde selectivity than that of the La-free conventional Fe2(MoO4)3 catalytic formulation.
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Evidence of ferroelectricity in La 2Zr 2O 7thin films with a frustrated pyrochlore-type structure. Acta Crystallogr A Found Adv 2015. [DOI: 10.1107/s2053273315092402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Abstract
The cubic BaCoO(∼2.2) was announced in the early 50's as the final product of high temperature self-reduction within the BaCoO(3-δ) series. However, apart from this report no clear characterization has been provided to date. Here, we confirm after the preparation of single crystal and powder samples that in this compound the ratio of oxygen vacancies is close to 27% in absence of any long range ordering. It follows that BaCoO(2.22) appears as the most oxygen deficient cubic perovskite stabilized at room temperature, its tolerance factor being displaced close to 1 by the combination of large Ba(2+) and Co(2/3+) ions in the A and B sites. The tolerance factor plays a limiting role for re-oxidation and fluorination using topochemical routes, despite the high concentration of available vacancies. Single crystal XRD data and DFT structural relaxation show that the Co sites are off-centered inside pseudo-tetrahedra leading to reinforced magnetic exchanges. Robust antiferromagnetic ordering is suggested to occur above 400 K while this compound shows a semi-conducting behavior. It was also possible to prepare an even more reduced mixed metallic phase of formula BaCo(0.5)Fe(0.5)O(2.16).
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Investigation of New Alkali Bismuth Oxosulfates and Oxophosphates with Original Topologies of Oxo-Centered Units. Inorg Chem 2014; 53:12058-65. [DOI: 10.1021/ic501776h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Reversible Topochemical Exsolution of Iron in BaFe2+2(PO4)2. Angew Chem Int Ed Engl 2014; 53:13365-70. [DOI: 10.1002/anie.201404476] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 08/07/2014] [Indexed: 11/10/2022]
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Use of Precession Electron and X Powder for solution and refinement of materials. Acta Crystallogr A Found Adv 2014. [DOI: 10.1107/s205327331409072x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
This communication will present the case study of ALa5O5(VO4)2 (A= Li, Na, K, Rb), example of the use of a combination of Precession Electron and X-ray Powder Data for the solution and the refinement of new materials. Indeed, an original structural type has been evidenced in the system (A, La, V, O) with A=Li, Na, K, Rb. Attempts to solve the structure ab initio on X-ray powder data were unsuccessful (more particularly because the powder was a mixture of the title compound and of unreacted precursors). The structure was finally solved by charge flipping using Precession Electron Data (3D tomography) on a nanocrystal, enabling a posteriori the good formulation of a pure powder. This powder was then classically refined by Rietveld method showing the correctness of the electron-solved structure. It crystallizes in a monoclinic unit cell with space group C2/m and a=20.2282(14) b=5.8639(4) c=12.6060(9) Å and β=117.64(1)0. The ALa5O5(VO4)2 structure is built of (OLa4) tetrahedral units creating Crenel-like 2D ribbons. These ribbons, surrounded by four isolated VO4 tetrahedra, are creating channels parallel to b axis in which A+ ions are located.
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Labile Degree of Disorder in Bismuth-Oxophosphate Compounds: Illustration through Three New Structural Types. Inorg Chem 2013; 53:861-71. [DOI: 10.1021/ic402930d] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Multidimensional Open-Frameworks: Combinations of One-Dimensional Channels and Two-Dimensional Layers in Novel Bi/M Oxo-Chlorides. Inorg Chem 2013; 53:528-36. [DOI: 10.1021/ic402578m] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Possible cationic ordering in bismuth oxide phosphates. Acta Crystallogr A 2013. [DOI: 10.1107/s0108767313099704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Phase homology in new layered mixed Li, M (M=Mg, Cu, Cd, Pb, Bi) bismuth oxophosphates and oxoarsenates. J SOLID STATE CHEM 2013. [DOI: 10.1016/j.jssc.2012.11.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Microstructural investigations and nanoscale ferroelectric properties in lead-free Nd2Ti2O7 thin films grown on SrTiO3 substrates by pulsed laser deposition. CrystEngComm 2013. [DOI: 10.1039/c3ce40256h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Two-Dimensional Antiferromagnetism in the [Mn3+xO7][Bi4O4.5−y] Compound with a Maple-Leaf Lattice. Angew Chem Int Ed Engl 2012; 51:9393-7. [DOI: 10.1002/anie.201203775] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Indexed: 11/08/2022]
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Phase homology and structural prediction in extended series of inorganic bi-based compounds. Acta Crystallogr A 2012. [DOI: 10.1107/s0108767312099953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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From simple O(Bi, M) 4entities to the large family of bismuth-based oxyphosphate compounds: use of high-resolution electron microscopy imaging to the deduction of new structure types. Acta Crystallogr A 2012. [DOI: 10.1107/s0108767312099102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Predictive approach of new bismuth oxo-phosphates. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311090891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Building 3D materials from adjustable 2D-units; towards the Design of new Bi-based compounds. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/opl.2011.98] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTIn the Bi2O3-MO-P2O5 diagram, on the basis of previous compounds based on 2D-ribbon like units, we have predicted and prepared the infinite term. It contains [Bi2O2]2+ planes arranged within a never-observed crystallographic form. In this series, the ribbons-like units are polycations built on the linkage of n O(Bi,M)4 tetrahedra along their width and infinite in a perpendicular dimension. Hence, this novel form completes the continuous series of analogue compounds, whose building units now extend from the single chain to the infinite plane, via a number of discrete n values (2,3,4,5,6,7,8,9,10,11). The presented materials of formulae Bi4MP2O12 (M= Zn and Mg) roughly show the same crystal structure. However different arrangements of the groups located between the [Bi2O2]2+ planes are at the origin of a complex superstructure in the case of the zinc compounds.
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Structural Features of the Modulated BiCu2(P1-xVx)O6Solid Solution; 4-D Treatment ofx= 0.87 Compound and Magnetic Spin-Gap to Gapless Transition in New Cu2+Two-Leg Ladder Systems. J Am Chem Soc 2006; 128:10857-67. [PMID: 16910681 DOI: 10.1021/ja0631091] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The BiCu(2)(P(1-x)V(x))O(6) system shows the appearance of various phenomena that progressively change as a function of the average (P/V)O(4) groups size. Then, from x = 0 to x approximately 0.7, a solid solution exists with respect to the basic orthorhombic unit cell of BiCu(2)PO(6). For greater x values (0.7 < x <0.96), structural modulations with incommensurate q vector that slightly change versus x appear. The 4-D treatment of single-crystal XRD data of the modulated phase corresponding to x = 0.87 at 100 K (orthorhombic, a = 12.379(3)Angstrom, b = 5.2344(9) Angstrom, c = 7.8270(14) Angstrom, q = 0.268(3) b*, super space group: Xbmm(0gamma0) s00, X stands for the nonprimitive centering vector (1/2,0,1/2,1/2), R(obs)(overall) = 5.27%, R(obs)(fundamental) = 4.48%, R(obs)(satellite) = 6.58%) has evidenced strong positional modulated effects within the [BiCu(2)O(2)](3+) ribbons while three XO(4) configurations compete along the x(4) fourth dimension. There is no P/V segregation along x(4) in good agreement with steric-only origins of the modulation. Finally for 0.96 < x <1, two phases coexist, i.e., BiCu(2)VO(6) (X = 1) and a modulated phase of the previous domain.The BiCu(2)VO(6) crystal structure shows a unit cell tripling associated with monoclinic symmetry lowering. The VO(4) orientations between two ribbons proceed with respect to the interribbon distance. Then the full system shows flexible interactions between modulated Bi/M/O-based ribbons and surrounding tetrahedral groups, depending on the average XO(4) size. Furthermore, between two ribbons the Cu(2+) arrangement forms magnetically isolated zigzag copper two-leg ladders. Our preliminary results show a spin-gap behavior likely due to the existence of true S = (1)/(2) Heisenberg two-leg ladders. Modulated compositions are gapless, in good agreement with band-broadening toward a continuum in the magnetic excitation spectrum. The continuous distribution of Cu-Cu distances along the rungs and legs of the ladders should be mainly responsible for this magnetic change.
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Bi3+/M2+ Oxyphosphate: A Continuous Series of Polycationic Species from the 1D Single Chain to the 2D Planes. Part 1: From HREM Images to Crystal-Structure Deduction. Inorg Chem 2006; 45:6604-11. [PMID: 16903714 DOI: 10.1021/ic060342r] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This work deals with the crystal-structure deduction of new structural types of Bi3+-M2+ oxyphosphates (M is a transition element) from HREM images. Previous studies showed the unequivocal attribution of particular HREM contrasts to the corresponding Bi/M/O-based polycationic species in similar materials. On this basis, the examination of isolated crystallites of polyphased samples led to new HREM contrasts assigned to new polycationic species in three new structural types. This helped us to solve one crystal structure, and the two other forms have been deduced through HREM image decoding. It helped to model the investigated materials from the structural point of view as well as the chemical one. The three assumed crystal structures are formed by polycationic ribbons, n tetrahedra wide, surrounded by PO4 groups, as already encountered in these series of oxyphosphates. However, here we deal with the original n= 4-6 cases, whereas, up to this work, only the n= 1-3 ribbons have been reported. The greater size of ribbons is associated with particular structural modifications responsible for complex HREM contrasts. The validity of the proposed models is verified in Part 2 of this work.
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Bi3+/M2+ Oxyphosphate: A Continuous Series of Polycationic Species from the 1D Single Chain to the 2D Planes. Part 2: Crystal Structure of Three Original Structural Types Showing a Combination of New Ribbonlike Polycations. Inorg Chem 2006; 45:6612-21. [PMID: 16903715 DOI: 10.1021/ic060343j] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
With the assistance of structural models deduced from the high-resolution electron microscope (HREM) investigation presented in Part 1 of this work, three new structural types were pointed out in Bi2O3-MO-P2O5 ternary systems. Their crystal structures are built on the arrangement of 2D polycationic ribbons formed of edge-sharing O(Bi,M)4 tetrahedra and isolated by PO4 groups. Prior to this study, materials with ribbons up to n = 3 tetrahedra wide have been discovered. The original structures presented here display longer n = 4-6 cases, which suggests a possible continuous series of polycationic entities that range from the single chain (one tetrahedron wide) to the infinite [Bi2O2]2+ Aurivillius layer. The ribbons with n > 3 show strong structural modifications that are able to bring a good ribbon-phosphate cohesion. In addition to these fascinating structural results, this work fully confirms the validity of the decoding established from HREM images of a single crystallite in inhomogeneous mixtures.
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Bi∼3.785Cd∼3.575Cu∼1.5(PO4)3.5O5.5, a new arrangement of double () and triple () [M4Bi2n−2O2n]x+ polycationic ribbons in the bismuth-transition metal oxy-phosphate series. J SOLID STATE CHEM 2004. [DOI: 10.1016/j.jssc.2004.06.057] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Double (n=2) and triple (n=3) [M4Bi2n−2O2n]x+ polycationic ribbons in the new Bi∼3Cd∼3.72M∼1.28O5(PO4)3 oxyphosphate (M=Co, Cu, Zn). J SOLID STATE CHEM 2003. [DOI: 10.1016/s0022-4596(03)00413-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Characterization of the new Bi∼6.2Cu∼6.2O8(PO4)5 oxyphosphate; a disordered compound containing 2- and 3-O(Bi, Cu)4 tetrahedra—wide polycationic ribbons. J SOLID STATE CHEM 2003. [DOI: 10.1016/s0022-4596(02)00080-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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