Polymorphisme (chimie)

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Publications associées (32)

Effects of Ball Milling and TiF3 Addition on the Dehydrogenation Temperature of Ca(BH4)2 Polymorphs

Andreas Züttel

The changes introduced by both ball milling and the addition of small amounts of TiF3 in the kinetics of the hydrogen desorption of three different Ca(BH4)2 polymorphs (α, β and γ) have been systematically investigated. The samples with different polymorph ...

2020

Raman spectroscopy and lattice dynamics calculations of tetragonally-structured single crystal zinc phosphide (Zn3P2) nanowires

Anna Fontcuberta i Morral, Elias Zsolt Stutz, Jean-Baptiste Leran, Mahdi Zamani, Simon Robert Escobar Steinvall, Rajrupa Paul, Mirjana Dimitrievska

Earth-abundant and low-cost semiconductors, such as zinc phosphide (Zn3P2), are promising candidates for the next generation photovoltaic applications. However, synthesis on commercially available substrates, which favors the formation of defects, and cont ...

2020

Diffraction artefacts from twins and stacking faults, and the mirage of hexagonal, polytypes or other superstructures

Cyril Cayron

Recently, a hexagonal phase has been reported in high carbon steels in several studies. Here, we show that the electron microscopy results used in these studies were erroneously interpreted. The extra-spots in the diffraction patterns and the odd contrasts ...

2020

Patterns and driving forces of dimensionality-dependent charge density waves in 2H-type transition metal dichalcogenides

László Forró, Helmuth Berger

Charge density wave (CDW) is a startling quantum phenomenon, distorting a metallic lattice into an insulating state with a periodically modulated charge distribution. Astonishingly, such modulations appear in various patterns even within the same family of ...

Nature Research2020

Electrochemical reconstruction of ZnO for selective reduction of CO2 to CO

Andreas Züttel, Emanuele Moioli, Wen Luo, Kun Zhao, Jie Zhang, Qin Zhang

Electrocatalytic conversion of CO2 to valuable chemicals is a highly promising route to close the carbon cycle. Herein, Zn catalysts derived from electrochemical reconstruction of ZnO materials are presented as efficient CO2-to-CO catalysts. We found that ...

2020

Surface-induced reversal of a phase transformation for the synthesis of epsilon-Fe2O3 nanoparticles with high coercivity

A metastable 8-polymorph of iron(III) oxide (epsilon-Fe2O3) is a very attractive material from the technological, engineering, and scientific points of view. In comparison with other iron oxides, it is characterized by unusual magnetic properties and a gia ...

PERGAMON-ELSEVIER SCIENCE LTD2020

Large magnetoresistance and nonzero Berry phase in the nodal-line semimetal MoO2

Oleg Yazyev, Quansheng Wu, Shengnan Zhang, Huancheng Chen

We performed calculations of the electronic band structure and the Fermi surface as well as measured the longitudinal resistivity rho(xx)(T,H), Hall resistivity rho(xy)(T,H), and quantum oscillations of the magnetization as a function of temperature at var ...

2020

TiO2- based ceramics, from basic science to applications

Nanomaterials and nanoparticles are nowadays used in a wide range of applications; from sunscreens, paint and food industry to catalytic processes, lighting, TV's and displays, their presence is percolating in our daily life. New applications rise every da ...

EPFL2020

Deciphering crystal packing effects in the spin crossover of six [Fe-II(2-pic)(3)]Cl-2 solvatomorphs

Sergio Vela Llausi

In this work we investigate how the crystal packing affects the spin crossover (SCO) of [Fe-II(2-pic)(3)]Cl-2. Four alcohol solvatomorphs of this compound have been reported to present a transition from a singlet low spin (LS, S = 0) to a quintet high spin ...

ROYAL SOC CHEMISTRY2019

Bulk single-crystal growth of the theoretically predicted magnetic Weyl semimetals RAlGe (R = Pr, Ce)

Jonathan White, Neeraj Kumar

We explore two methods for single-crystal growth of the theoretically proposed magnetic Weyl semimetals RAlGe (R = Pr, Ce), which prove that a floating-zone technique, being both crucible- and flux-free, is crucial to obtain perfectly stoichiometric RAlGe ...

AMER PHYSICAL SOC2019

Synthesis of Pure Brookite Nanorods in a Nonaqueous Growth Environment

Mohammad Khaja Nazeeruddin, Mahmoud Saeed Qaid Mohammad Hezam

Brookite TiO2 is the most difficult TiO2 polymorph to synthesize. The available methods in the literature to produce brookite nanostructures mostly use water-based techniques for the preparation of water-soluble Ti complexes first, followed by a hydrotherm ...

2019

Enhanced mineralization of atrazine by surface induced hydroxyl radicals over light-weight granular mixed-quartz sands with ozone

Stefanos Giannakis, Jun Ma, Da Wang, Shuang Song

A light-weight granular mixed-quartz sand (denoted as L-GQS) combined with stirring-assisted bubble column reactor was firstly applied in catalytic ozonation of atrazine. The L-GQS, with a density of 2.36 g cm(-3) and average diameter of ca. of 4 mm, was r ...

PERGAMON-ELSEVIER SCIENCE LTD2019

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