Synthesis and Raman micro-spectroscopy investigation of Li7La3Zr2O12

The Li+ ion conductor Li7La3Zr2O12 was synthesized by solid state reaction as a ceramic with tetragonal and cubic crystal structure. The synthesis parameterswere varied for these polycrystalline samples, e.g. the starting materials for Li and Zr, the cruciblematerials and the thermal treatments. Product formation is sensitive to the ZrO2 starting powder aswell as the crucible material due to reactions between the powdermixture and the cruciblewall. In this study, only the use of an alumina crucible or the addition of alumina resulted in the successful preparation of cubic Li7La3Zr2O12. For single-crystal preparation, flux growth experiments were carried out at 1000 and 1200 \ub0C either in alumina crucibles lined with a gold foil or in magnesia crucibles and using Li2CO3 (Li2O) as flux. The small crystals were separated from the solidified flux by washing larger lumps in water. Irrespective of the additions of alumina, only tetragonal micro-crystals of Li7La3Zr2O12 were obtained. These micro-crystals were studied by micro-Raman scattering spectroscopy. Polarized Raman spectra were recorded either in nearly backscattering or 90\ub0 geometry. The majority of Raman modes expected for the tetragonal phase (space group I41/acd, Z=8) were satisfactorily displayed. So far, it has not been possible to make unambiguous symmetry assignments of the observed peaks because of the unknown orientation of the micro-crystals

Promotion of mixed protonic–electronic transport in La5.4_{5.4}WO11.1−δ_{11.1− δ} membranes under H2_2S atmospheres

Catalytic membrane reactors (CMR) based on H$_2$-separation membranes can improve the performance of thermodynamically-limited reactions such as high-pressure steam methane reforming, ammonia cracking, non-oxidative aromatics production, and water gas shift reaction (WGS). In these industrial processes, the membrane surfaces are typically exposed to steam, CO$_2$, CO, H$_2$S, and hydrocarbons in combination with high temperatures. Therefore, the membrane materials require long-term thermo-chemical stability under the mentioned conditions. Stability in H$_2$S is of outstanding importance since its presence, even at ppm level, gives rise to substantial surface poisoning and decomposition of most materials. Here we characterize the influence of H$_2$S on the crystalline structure, lattice composition, and hydrogen-transport properties of La$_{5.4}$WO$_{11.1−δ}$, one of the reference protonic membrane materials. The incorporation of sulfide ions in the crystal lattice is ascertained from XRD, XPS, FESEM, WDS, EDS, and FIB-SIMS analyses. UV-vis spectroscopy and EIS measurements illustrate the effect of the incorporated sulfur in the transport properties, i.e., vigorously promoting the electronic conductivity mediated by the concurrent partial reduction of tungsten cations (W$^{6+}$). The rise in electronic conductivity allowed an H$_2$ flux of 0.042 mL cm$^{−2}$ min$^{−1}$ to be reached at 700 °C for a ∼700 μm-thick membrane, in contrast with negligible H$_2$ permeation in H$_2$S-free conditions

Internet-based psychoeducation for bipolar disorder: a qualitative analysis of feasibility, acceptability and impact

<p>Background: In a recent exploratory randomised trial we found that a novel, internet-based psychoeducation programme for bipolar disorder (Beating Bipolar) was relatively easy to deliver and had a modest effect on psychological quality of life. We sought to explore the experiences of participants with respect to feasibility, acceptability and impact of Beating Bipolar.</p> <p>Methods: Participants were invited to take part in a semi-structured interview. Thematic analysis techniques were employed; to explore and describe participants’ experiences, the data were analysed for emerging themes which were identified and coded.</p> <p>Results: The programme was feasible to deliver and acceptable to participants where they felt comfortable using a computer. It was found to impact upon insight into illness, health behaviour, personal routines and positive attitudes towards medication. Many participants regarded the programme as likely to be most beneficial for those recently diagnosed.</p> <p>Conclusions: An online psychoeducation package for bipolar disorder, such as Beating Bipolar, is feasible and acceptable to patients, has a positive impact on self-management behaviours and may be particularly suited to early intervention. Alternative (non-internet) formats should also be made available to patients.</p&gt

Al13H−: Hydrogen atom site selectivity and the shell model

Using a combination of anion photoelectron spectroscopy and density functional theory calculations, we explored the influence of the shell model on H atom site selectivity in Al13H−. Photoelectron spectra revealed that Al13H− has two anionic isomers and for both of them provided vertical detachment energies (VDEs). Theoretical calculations found that the structures of these anionic isomers differ by the position of the hydrogen atom. In one, the hydrogen atom is radially bonded, while in the other, hydrogen caps a triangular face. VDEs for both anionic isomers as well as other energetic relationships were also calculated. Comparison of the measured versus calculated VDE values permitted the structure of each isomer to be confirmed and correlated with its observed photoelectron spectrum. Shell model, electron-counting considerations correctly predicted the relative stabilities of the anionic isomers and identified the stable structure of neutral Al13H

A Vanadium(III) Complex with Blue and NIR-II Spin-Flip Luminescence in Solution

Luminescence from Earth-abundant metal ions in solution at room temperature is a very challenging objective due to the intrinsically weak ligand field splitting of first-row transition metal ions, which leads to efficient nonradiative deactivation via metal-centered states. Only a handful of 3dn metal complexes (n ≠ 10) show sizable luminescence at room temperature. Luminescence in the near-infrared spectral region is even more difficult to achieve as further nonradiative pathways come into play. No Earth-abundant first-row transition metal complexes have displayed emission >1000 nm at room temperature in solution up to now. Here, we report the vanadium(III) complex mer-[V(ddpd)2][PF6]3 yielding phosphorescence around 1100 nm in valeronitrile glass at 77 K as well as at room temperature in acetonitrile with 1.8 × 10–4% quantum yield (ddpd = N,N′-dimethyl-N,N′-dipyridine-2-ylpyridine-2,6-diamine). In addition, mer-[V(ddpd)2][PF6]3 shows very strong blue fluorescence with 2% quantum yield in acetonitrile at room temperature. Our comprehensive study demonstrates that vanadium(III) complexes with d2 electron configuration constitute a new class of blue and NIR-II luminophores, which complement the classical established complexes of expensive precious metals and rare-earth elements

In-depth exploration of the photophysics of a trinuclear palladium complex

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