Reversible water induced phase changes of cobalt oxide nanoparticles

Cobalt oxides have been identified as highly active catalysts for the electrochemical water splitting and oxygen evolution reaction. Using near ambient pressure resonant photoelectron spectroscopy, we studied changes in the metal amp; 8722;oxygen coordination of size selected core amp; 8722;shell CoOx nanoparticles induced by liquid water. Indry conditions, the nanoparticles exhibit an octahedrally coordinated Co2 core and a tetrahedrally coordinated Co2 shell. In the presence of liquid water, we observe a reversible phase change of the nanoparticle shell into octahedrally coordinated Co2 as well as partially oxidized octahedrally coordinated Co3 . This is in contrast to previous findings, suggesting an irreversible phase change of tetrahedrally coordinated Co2 after the oxygen evolution reaction conditioning. Our results demonstrate the appearance of water induced structural changes different from voltage induced changes and help us to understand the atomic scale interaction of CoOx nanoparticles with water in electrochemical processe

Dynamic observation of manganese adatom mobility at perovskite oxide catalyst interfaces with water

Real time in situ microscopy imaging of surface structure and atom dynamics of heterogeneous catalysts is an important step for understanding reaction mechanisms. Here, using in situ environmental transmission electron microscopy ETEM , we directly visualize surface atom dynamics at manganite perovskite catalyst surfaces for oxygen evolution reaction OER , which are amp; 8805;20 times faster in water than in other ambients. Comparing 001 surfaces of La0.6Sr0.4MnO3 and Pr0.67Ca0.33MnO3 with similar initial manganese valence state and OER activity, but very different OER stability, allows us to distinguish between reversible surface adatom dynamics and irreversible surface defect chemical reactions. We observe enhanced reversible manganese adatom dynamics due to partial solvation in adsorbed water for the highly active and stable La0.6Sr0.4MnO3 system, suggesting that aspects of homogeneous catalysis must be included for understanding the OER mechanism in heterogeneous catalysi

Resonant X ray photoelectron spectroscopy identification of atomic contributions to valence states

Valence electronic structure is crucial for understanding and predicting reactivity. Valence non resonant Xray photoelectron spectroscopy NRXPS provides a direct method for probing the overall valence electronic structure. However, it is often difficult to separate the varying contributions to NRXPS; for example, contributions of solutes in solvents or functional groups in complex molecules. In this work we show that valence resonant X ray photoelectron spectroscopy RXPS is a vital tool for obtaining atomic contributions to valence states. We combine RXPS with NRXPS and density functional theory calculations to demonstrate the validity of using RXPS to identify atomic contributions for a range of solutes both neutral and ionic and solvents both molecular solvents and ionic liquids . Furthermore, the one electron picture of RXPS holds for all of the closed shell molecules ions studied, although the situation for an open shell metal complex is more complicated. Factors needed to obtain a strong RXPS signal are investigated in order to predict the types of systems RXPS will work best for; a balance of element electronegativity and bonding type is found to be important. Additionally, the dependence of RXPS spectra on both varying solvation environment and varying local covalent bonding is probed. We find that RXPS is a promising fingerprint method for identifying species in solution, due to the spectral shape having a strong dependence on local covalency but a weak dependence on solvation environmen

Resonant X-ray photoelectron spectroscopy: identification of atomic contributions to valence states.

Valence electronic structure is crucial for understanding and predicting reactivity. Valence non-resonant X-ray photoelectron spectroscopy (NRXPS) provides a direct method for probing the overall valence electronic structure. However, it is often difficult to separate the varying contributions to NRXPS; for example, contributions of solutes in solvents or functional groups in complex molecules. In this work we show that valence resonant X-ray photoelectron spectroscopy (RXPS) is a vital tool for obtaining atomic contributions to valence states. We combine RXPS with NRXPS and density functional theory calculations to demonstrate the validity of using RXPS to identify atomic contributions for a range of solutes (both neutral and ionic) and solvents (both molecular solvents and ionic liquids). Furthermore, the one-electron picture of RXPS holds for all of the closed shell molecules/ions studied, although the situation for an open-shell metal complex is more complicated. The factors needed to obtain a strong RXPS signal are investigated in order to predict the types of systems RXPS will work best for; a balance of element electronegativity and bonding type is found to be important. Additionally, the dependence of RXPS spectra on both varying solvation environment and varying local-covalent bonding is probed. We find that RXPS is a promising fingerprint method for identifying species in solution, due to the spectral shape having a strong dependence on local-covalency but a weak dependence on the solvation environment

How do patients from eastern and western Germany compare with regard to their preferences for shared decision making?

Item does not contain fulltextBACKGROUND: Increasing emphasis is being placed on involving patients in decisions concerning their health. This shift towards more patient engagement by health professionals and towards more desire by patients for participation may be partly based on socio-political factors. METHODS: To compare the preferences for shared decision making of patients from eastern and western Germany we analysed five patient samples (n = 2318) (general practice patients and schizophrenia patients from eastern and western Germany). Patients' role preferences for shared decisions were measured using the decision-making subscale of the Autonomy Preference Index. RESULTS: Patients resident in eastern Germany expressed lower preferences for shared decision making than patients in western Germany. This was true after controlling for socio-demographic variables and for patient group. CONCLUSION: The cultural imprint (e.g. western vs. former communist society) seems to have a significant influence on patients' expectations and behaviour in the medical encounter. Health services providers need to be aware that health attitudes within the same health system might vary for historical and cultural reasons. The engagement of patients in medical decisions might not be susceptible to a 'one size fits all' approach; doctors should instead aim to accommodate the individual patient's desire for autonomy.1 augustus 201