Influence of Vacancies in Manganese Hexacyanoferrate Cathode for Organic Na‐Ion Batteries: A Structural Perspective

Manganese hexacyanoferrates (MnHCF) are promising positive electrode materials for non-aqueous batteries, including Na-ion batteries, due to their large specific capacity (>130 mAh g$^{–1}$), high discharge potential and sustainability. Typically, the electrochemical reaction of MnHCF associates with phase and structural changes, due to the Jahn-Teller (JT) distortion of Mn sites upon the charge process. To understand the effect of the MnHCF structure on its electrochemical performance, two MnHCF materials with different vacancies content are investigated herein. The electrochemical results show that the sample with lower vacancy content (4 %) exhibits relatively higher capacity retention of 99.1 % and 92.6 % at 2$^{nd}$ and 10$^{th}$ cycles, respectively, with respect to 97.4 % and 79.3 % in sample with higher vacancy content (11 %). Ex-situ X-ray absorption spectroscopy (XAS) and ex situ X-ray diffraction (XRD) characterization results show that a weaker cooperative JT-distortion effect and relatively smaller crystal structure modification occurred for the material with lower vacancies, which explains the better electrochemical performance in cycled electrodes

Titania Thin Film Coated Glass for Simultaneous Ammonia Degradation and UV Light Blocking Layer in Photovoltaics

In this work, we have investigated the potential dual application of TiO2 thin films as a photocatalyst for ammonia degradation, and as a UV light blocking layer in c-Si photovoltaics. For this purpose, we deposited a series of TiO2 thin films on a glass substrate by reactive magnetron sputtering and analysed the influence of the deposition parameters (O2/Ar working gas content and pressure) on the structural, optical and photocatalytic properties. All samples are nanocrystalline anatase TiO2 and have a uniform surface (RMS roughness < 5 nm) in a wide range of magnetron sputtering deposition parameters. They are transparent in the Vis/NIR spectral range and strongly absorb light in the UV range above the optical bandgap energy (3.3 eV), which makes them suitable for the use as UV blocking layers and photocatalysts. The photocatalytic properties were studied in a mini-photocatalytic wind tunnel reactor by examining ammonia degradation. A kinetic study was performed to estimate the reaction rate constants for all samples. The intrinsic reaction rate constant confirmed the crucial role of surface morphology in ammonia decomposition efficiency

Supporting Information: Unexpected chain of redox events in co-based Prussian blue analogues

Comprehensive characterizing information about the series of materials; crystal, composition, and hyperfine parameters of the 57Fe Mössbauer spectra of samples K2−δMn1–xCox[Fe(CN)6]; SAED and TGA patterns, HAADF-STEM images, ATR–FTIR, 57Fe Mössbauer spectra, and electrochemical galvanostatic profiles of the mentioned series of samples; calculated fit of XAS experiments; and plots of KCMF50 and KCF operando SXRD in a 10–54° 2Θ range (λ = 1.0332 Å).Peer reviewe

Intrinsic phase separation in superconducting K0.8Fe1.6Se2 (Tc= 31.8 K) single crystals

Temperature dependent single-crystal x-ray diffraction (XRD) in transmission mode probing the bulk of the newly discovered K0.8Fe1.6Se2 superconductor (Tc = 31.8 K) using synchrotron radiation is reported. A clear evidence of intrinsic phase separation at 520 K between two competing phases, (i) a first majority magnetic phase with a ThCr2Si2-type tetragonal lattice modulated by the iron vacancy ordering and (ii) a minority non-magnetic phase having an in-plane compressed lattice volume and a weak superstructure, is reported. The XRD peaks due to the Fe vacancy ordering in the majority phase disappear by increasing the temperature at 580 K, well above phase separation temperature confirming the order-disorder phase transition. The intrinsic phase separation at 520K between a competing first magnetic phase and a second non-magnetic phase in the normal phase both having lattice superstructures (that imply different Fermi surface topology reconstruction and charge density) is assigned to a lattice-electronic instability of the K0.8Fe1.6Se2 system typical of a system tuned at a Lifshitz critical point of an electronic topological transition that gives a multi-gaps superconductor tuned a shape resonance.Comment: 10 pages, 4 figure

Cyclops: New modular software suite for cryo-EM

,rain designed as a graphical front-cild that allows easy control and interaction with tasks and programs is a new computer grams for 3D reconstruction of biological complexes using cryo-electron microscopy. Cyclops' current plug-his are designed for automated particle picking and include two new algorithms, automated carbon masking and quaternion based rotation space sampling, which are also presented here. Additional plug-ins are in the pipeline. Cyclops allows straightforward organization and visualization of all data and tasks and allows both interactive and batch-wise processing. Furthermore, it was designed for straightforward implementation in grid architectures. As a front-end to a collection of programs it provides a common interface to these programs, thus enhancing the usability of the suite and the productivity Of the User. (c) 2006 Elsevier Inc. All rights reserved

Fast fabrication over large areas of P3HT nanostructures with high supramolecular order

The fabrication of P3HT nanopatterns (lamellae and fibres) within a few minutes, in standard laboratory conditions (i.e., at room temperature and in air) and over areas as large as cm2, is reported. The nanostructures are prepared using a wet-processing method. A satisfactory control over the pattern topology (lamellae, hierarchically connected and parallel fibres, entangled but disconnected and quasiparallel fibres, randomly oriented fibres) is obtained by simply changing one process parameter. UV-vis spectroscopy and X-ray diffraction analyses carried out over the so-fabricated structures evidence a very high degree of supramolecular organization of the polymeric chains. Such a degree of order is similar or even better than that of P3HT samples treated with thermal or solvent annealing procedures

Role of the thermal treatment on the microstructure of YAGG nanopowders prepared by urea glass route

Yttrium aluminium gallium garnet (YAGG, Y3Al2Ga3O12) doped with rare-earth ions has drawn large attention owing to its optical properties with applications ranging from persistent luminescent phosphors to nanothermometers. Herein, three different YAGG materials were synthesized via the urea glass route followed by thermal treatment, relatively undoped; doped with Ce3+, Cr3+, and Nd3+; and doped with Ce3+, Cr3+, and Yb3+. The garnet formation was studied in situ upon thermal treatment from 300 to 1000 °C using synchrotron powder diffraction. Our results show that with this method, the onset of formation of the garnet is about 860 °C, with comparable cell parameters for both undoped and doped YAGG. A possible growth mechanism of YAGG is therefore discussed on the basis of observed microstructural parameters such as occupancy, microstrain, and crystallite size.We are grateful to Elettra-Sincrotrone Trieste for providing beamtime and financial support for the XRPD experiment (proposal nr. 20170489, Role of the thermal treatment on the composition and microstructural evolution of YAG nanoparticles). FA thanks MIUR for the Project ‘PON Ricerca e Innovazione 2014–2020 – Avviso DD 407/2018’ “AIM Attrazione e Mobilità Internazionale” (AIM1808223). M.G. wishes to thank Alessandro Olivo (Elettra-Sincrotrone Trieste) for the help with the setting and tuning of the Arduino PID and Chiara Milanese (Pavia H2 Lab, Chemistry Department and CSGI - Pavia University) for the support.Peer reviewe

Structural study of Yb3+, Eu3+ and Pr3+ doped Ca9Lu(PO4)7

The whitlockite-like crystal structure of Ca9Lu(PO4)7 when doped with several ions (Yb3+, Eu3+ and Pr3+) at different concentrations (1 mol.%, 5 mol.% and 10 mol.%) was studied, by means of synchrotron X-ray diffraction. In particular for Eu3+ and Pr3+, the presence of the dopant ion significantly changed the occupation factors (OF's) of the Ca2+ and Lu3+ cations and gave rise to a distortion of the metal-oxygen polyhedra. The observed structural features clearly showed significant impact of the dopant ion on the crystal structure of the host

Structural characterization of the CeO2/Gd2O3 mixed system by synchrotron x-ray diffraction

The structural determination of the CeO2/Gd2O3 mixed system is a non-trivial problem because of the close resemblance between the ionic sizes of Ce4+ and Gd3+ and between the crystal structures of CeO2 and Gd2O3. (Ce1 12xGdx)O2 12x/2 powder samples with x ranging between 0 and 1 have been synthesized by coprecipitation of mixed oxalates and subsequent thermal decomposition in air at 1200 \ub0C followed by slow cooling. Synchrotron powder X-ray diffraction data were collected and refined by the Rietveld method. Lattice parameters do not follow Vegard's law and no peak splitting has been observed for any composition, meaning that no biphasic regions exist over the whole compositional range. The same hybrid structural model \u2013 a proper mixture of the structures of the two pure oxides \u2013 was used for the refinements, allowing to account for the data observed