TY - JOUR A1 - Joubert, J.M. A1 - Crivello, J.C. A1 - Yusenko, Kirill T1 - Modification of Lu's (2005) high pressure model for improved high pressure/high temperature extrapolations. Part II: Modeling of osmium-platinum system at high pressure/high temperature N2 - In Part I of this paper, we have described a modification brought to the model of Lu (X.-G. Lu et al., Comput. Coupling Phase Diagr. Thermochem. 29 (2005) 49–55) in order to avoid extrapolation problems at high pressure and temperature. We now extend this approach to the study of a binary system: Os–Pt. For this, a complete description (equation of state) of Os at high pressure/high temperature is provided including the liquid phase. The thermodynamic assessment of the system Os–Pt has been carried out at ambient pressure by the Calphad method. All this study has been supported by first principles, special quasi-random structure (including under high pressure) and phonon calculations. Finally, using the high pressure description of metastable structures (hcp Pt and fcc Os), we have been able to obtain by extrapolation a complete description of Os–Pt system up to 500 GPa. Recent experimental data for Os–Pt system obtained up to 50 GPa at various temperatures up to 2300 °C may us allow to validate our modeling approach. KW - Phase diagrams KW - High-pressure PY - 2021 DO - https://doi.org/10.1016/j.calphad.2021.102311 VL - 74 SP - 102311 PB - Elsevier AN - OPUS4-54005 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fedorova, E.A. A1 - Asanov, Igor A1 - Yusenko, Kirill A1 - Asanova, T.I. A1 - La Fontaine, Camille A1 - Roudenko, olga A1 - Gerasimov, E.Y. A1 - Vasilchenko, D A1 - Korenev, S.V. T1 - Time-resolved study of thermal decomposition process of (NH4)(2) PtCl6 : Intermediates and Pt nucleation N2 - Evolution in crystal, electronic and local atomic structures of Pt in ammonium hexachloroplatinate in the course of thermal decomposition in inert and reducing atmospheres have been studied by Powder X-Ray Diffraction (PXRD) and Quick X-ray Absorption Fine Structure (QXAFS) at Pt L3-edge for deeper understanding the thermally-induced solid state reaction and the formation of metallic nanoparticles. A three-step thermal decomposition mechanism of (NH4)2[PtCl6] in the inert atmosphere with the intermediate products Pt(NH3)2Cl2 and PtCl2 has been found instead one-[G.Meyer, A.Möller, J. Less. Common. Met. 170 (1991) 327–331] and two-step one [Q.Kong, F.Baudelet, J.Han, S.Chagnot, L.Barthe, J.Headspith, R. Goldsbrough, F.E.Picca, O.Spalla, Sci. Rep. 2 (2012) 1018–1025] considered early. In the reducing atmosphere, the thermal decomposition is a two-step process with the formation of the intermediate PtCl2. The best approach to determining the number of thermal decomposition steps turned out to be the express-analysis of QXAFS spectra offered in the papers, based on the simultaneous presentation of the most important parameters extracted from X-ray Absorption Near Edge Structure (XANES) and Fourier transformed Extended XAFS (EXAFS). This express-analysis was tested by comparison with results of various approaches such as conventional EXAFS fitting, linear combination fit (LCF), Multivariate Curve Resolution Alternating Least Squares method (MCR ALS). KW - Platinum KW - Quick-EXAFS PY - 2021 DO - https://doi.org/10.1016/j.vacuum.2021.110590 VL - 194 SP - 110590 PB - Elsevier AN - OPUS4-54008 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Asanova, T.I. A1 - Asanov, Igor A1 - Yusenko, Kirill A1 - Le Fontane, Camille A1 - Gerasimov, E.Y. A1 - Zadesenetz, A.V. A1 - Korenev, S.V. T1 - Time-resolved study of Pd-Os and Pt-Os nanoalloys formation through thermal decomposition of Pd(NH3)(4) OsCl6 and Pt(NH3)(4) OsCl6 complex salts N2 - The formation mechanisms of Pd-Os and Pt-Os alloys in the course of thermal decomposition of iso-formular and isostructural complex salts [Pd(NH3)4][OsCl6] and [Pt(NH3)4][OsCl6] in an inert atmosphere have been studied by in-situ QXAFS, XPS and PXRD. The mechanisms of thermal decomposition of the precursors are found to differ from each other, but the detected intermediate products show no significant effect on the local atomic structure around Os, Pt/Pd in their final products. A crystalline beta-trans-[Pd(NH3)2Cl2] intermediate of the first step of thermal decomposition of [Pd(NH3)4][OsCl6] makes the anion [OsCl6]2− transform differently than that of [Pt(NH3)4][OsCl6]. It transforms into a short-lived [Os(NH3)xCl6-x] (2≤x≤4), and then to a distorted octahedron [OsCl6]2−, similar to the high-temperature modification of OsCl4. In case of [Pt(NH3)4][OsCl6], the intermediate [Os(NH3)2Cl4] modifies into four chlorine coordinated Os,{OsCl4}0/1−. Consecutive reduction of Pd(II)/Pt(II) and Os(IV) to the metals defines the homophilic atomic order with the fcc-Pd covered by a random Pd-Os alloy layer and Os on the surface, that is supported by High-Resolution Transmission Electron Mictroscopy (HRTEM) and Scanning TEM (STEM) energy dispersive X-ray (EDX) data, and the diffusion direction going from the surface (hcp-Os) to bulk (fcc-Pd/Pt). As a result, the heterogeneous alloys are formed with a very similar electronic and local atomic structure of Os and Pd/Pt. Upon alloying, the Os 5d5/2,3/2 and Pt 5d5/2,3/2 levels are depleted in the Pt-Os alloys compared to dispersed hcp-Os, fcc-Pt, and Pt foil. This is an unusual behaviour for Os and Pt, calling into question the versatility of d-band theory in bimetallic Os-alloys. The spin-orbit effect at the Os site has been found for both the Pd-Os and Pt-Os alloys, but it is about 4 times less compared to the complex salts. The obtained values for the complex compounds are comparable with those for the iridates, proposed as materials with spin-orbit-induced properties. KW - Thermal decomposition KW - Quick-EXAFS PY - 2021 DO - https://doi.org/10.1016/j.materresbull.2021.111511 VL - 144 SP - 111511 PB - Elsevier Ltd. AN - OPUS4-54010 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Serebrennikova, P. A1 - Komarov, V. A1 - Sukhikh, A. A1 - Khranenko, S. A1 - Zadesenetz, A. A1 - Gromilov, S A1 - Yusenko, Kirill T1 - [NiEn3](MoO4)0.5(WO4)0.5 co-crystals as single-source precursors for ternary refractory Ni-Mo-W alloys N2 - The co-crystallisation of [NiEn3](NO3)2 (En = ethylenediamine) with Na2MoO4 and Na2WO4 from a water solution results in the formation of [NiEn3](MoO4)0.5(WO4)0.5 co-crystals. According to the X-ray diffraction analysis of eight single crystals, the parameters of the hexagonal unit cell (space group P–31c, Z = 2) vary in the following intervals: a = 9.2332(3)–9.2566(6); c = 9.9512(12)–9.9753(7) Å with the Mo/W ratio changing from 0.513(3)/0.487(3) to 0.078(4)/0.895(9). The thermal decomposition of [NiEn3](MoO4)0.5(WO4)0.5 individual crystals obtained by co-crystallisation was performed in He and H2 atmospheres. The ex situ X-ray study of thermal decomposition products shows the formation of nanocrystalline refractory alloys and carbide composites containing ternary Ni–Mo–W phases. The formation of carbon–nitride phases at certain stages of heating up to 1000 °C were shown. KW - Single source precursors KW - Phase diagrams PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540123 DO - https://doi.org/10.3390/nano11123272 VL - 11 IS - 12 SP - 1 EP - 12 PB - MDPI CY - Basel AN - OPUS4-54012 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Yusenko, Kirill T1 - Single-source precursors strategy to access refractory high-entropy alloys for electrocatalytic applications N2 - High-entropy alloys containing up to 6 platinum group metals can be prepared by thermal decomposition of single-source precursors non requiring high temperature. We prepare the first example of a single-phase hexagonal high-entropy alloy. Heat treat- ment up to 1500 K and compression up to 45 GPa do not result in phase changes, a record temperature and pres- sure stability for a single-phase high-entropy alloy. The alloys show pronounced electrocatalytic activity in methanol oxidation, which opens a route for the use of high-entropy alloys as materials for sustainable energy conversion. T2 - HEA2020: first international virtual workshop on high-entropy alloy and complex solid solution nanoparticles for electrocatalysis CY - Online meeting DA - 06.10.2020 KW - High-entropy alloys KW - Single-source precursors PY - 2020 AN - OPUS4-54013 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Yusenko, Kirill A1 - Smekhova, A. A1 - Kuzmin, A. T1 - Extended X-Ray absorption fine structure (exafs) to study local constitution of high-entropy alloys N2 - Modern design of superior multi-functional alloys composed of several principal components requires in-depth studies of their local structure for developing desired macroscopic properties. Herein, peculiarities of atomic arrangements on the local scale and electronic states of constituent elements in the single-phase face-centered cubic (fcc)- and body-centered cubic (bcc)-structured high-entropy Alx-CrFeCoNi alloys (x = 0.3 and 3, respectively) are explored by element-specific X-ray absorption spectroscopy in hard and soft X-ray energy ranges. Simulations based on the reverse Monte Carlo approach allow to perform a simultaneous fit of extended X-ray absorption fine structure spectra recorded at K absorption edges of each 3d constituent and to reconstruct the local environment within the first coordination shells of absorbers with high precision. T2 - SPP2006: ordering in high-entropy alloys CY - Online meeting DA - 05.10.2021 KW - EXAFS KW - High-entropy alloys PY - 2021 AN - OPUS4-54015 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schönhals, Andreas T1 - Thermal behavior of high preformance polymers - Fast Scanning Calorimetry and more N2 - The glass tranistion behavior of polymers of intrinsic microporosity and polynornornes is discussed. T2 - Flash DSC Conference 2021 CY - Online meeting DA - 06.12.2021 KW - Polymer of Intrisic Maicroporosity KW - Highly permeable polynorbornenes PY - 2021 AN - OPUS4-53938 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Emmerling, Franziska T1 - Shaken not stirred: enhancing the flavor of mechanochemistry N2 - Mechanochemistry is increasingly used for synthesizing soft matter materials including metal organic compounds and cocrystals.1 The ever-increasing interest in this method is contrasted by a limited mechanistic understanding of the mechanochemical reactivity and selectivity. Time-resolved in situ investigations of milling reactions provide direct insights in the underlying mechanisms.2-4 We recently introduced different setups enabling in situ investigation of mechanochemical reactions using synchrotron XRD combined with Raman spectroscopy and thermography. The presented setup allows the detection of crystalline, amorphous, eutectic, and liquid intermediates. Furthermore, the chemical composition of the reaction mixture was found to be directly correlated with changes in the temperature profile of the reaction. The resulting deeper kinetic and thermodynamic understanding of milling processes is the key for future optimization of mechanochemical syntheses. In this contribution, we will discuss our recent results investigating the formation of (polymorphic) cocrystals and coordination polymers.2,3,5 Our results indicate that in situ investigation of milling reactions offer a new approach to tune and optimize mechanochemical syntheses. T2 - BCA/BACG joint spring meeting CY - Online meeting DA - 29.03.2021 KW - Mechanochemistry KW - Cocrystals KW - Crystal Engineering PY - 2021 AN - OPUS4-53995 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Emmerling, Franziska T1 - Shaken not stirred: in situ investigations of mechanochemical processes N2 - Mechanochemistry has emerged as one of the most interesting synthetic protocols to produce new materials. The development of mechanochemistry as a synthetic method is supported by excellent research by many groups worldwide in a wide range of applications. The potential of mechanochemistry is also reflected in the inclusion in IUPAC’s 10 chemical innovations that will change our world’.[1] Solvent-free methodologies lead to unique chemical processes during synthesis with the consequent formation of martials with new properties.2 In this contribution, we will discuss our recent results investigating the formation of (polymorphic) cocrystals, coordination polymers, metal oxides and metal nanoparticles.[3-8] We introduced different setups enabling in situ investigation of mechanochemical reactions using synchrotron XRD combined with Raman spectroscopy and thermography. T2 - Deutsche Kristallzüchtertagung CY - Berlin, Germany DA - 06.10.2021 KW - Mechanochemistry KW - In situ real-time monitoring KW - Crystal PY - 2021 AN - OPUS4-53996 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Emmerling, Franziska T1 - Scientific Writing - best practice tools N2 - Personal view of an experienced writer on how to write a paper. T2 - MatchingCamp 2021 CY - Bad Belzig, Germany DA - 08.11.2021 KW - Writing PY - 2021 AN - OPUS4-53999 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -