Generalized Poisson--Nernst--Planck-based physical model of O2_2 I LSM I YSZ electrode

The paper presents a generalized Poisson-Nernst-Planck model of an yttria-stabilized zirconia electrolyte developed from first principles of nonequilibrium thermodynamics which allows for spatial resolution of the space charge layer. It takes into account limitations in oxide ion concentrations due to the limited availability of oxygen vacancies. The electrolyte model is coupled with a reaction kinetic model describing the triple phase boundary with electron conducting lanthanum strontium manganite and gaseous phase oxygen. By comparing the outcome of numerical simulations based on different formulations of the kinetic equations with results of EIS and CV measurements we attempt to discern the existence of separate surface lattice sites for oxygen adatoms and O2- from the assumption of shared ones. Furthermore, we discern mass-action kinetics models from exponential kinetics models

Crystal structure of NaCd(H2PO3)3·H2O and spectroscopic study of NaM(H2PO3)3·H2O, M= Mn, Co, Ni, Zn, Mg and Cd

NaCd(H2PO3)3·H2O was synthesized in solution and its structure was studied by single-crystal X-ray diffraction. It crystallizes in the orthorhombic system (Pbca, Z = 8) with the cell parameters: a = 9.2895(14) Å, b = 15.124(2) Å, c = 15.0592(12) Å. Final residual factors R/Rw are 0.0297/0.0790. Both Na+ and Cd2+ are octahedrally coordinated, [NaO6] and [CdO6] share edges to form zigzag chains along [1 0 0]. The 3D framework is build upon these chains which are interconnected by H2PO3 pseudo-pyramids and an intricate network of weak hydrogen bonds. NaCd(H2PO3)3·H2O belongs the series of isostructural phosphites NaM(H2PO3)3·H2O (M = Mn, Co, Ni, Zn and Mg). IR spectroscopic studies show the bands confirming the presence of the phosphite H2PO32− anion in the whole series NaM(H2PO3)3·H2O, M = Mn, Co, Ni, Zn, Mg and Cd. The UV–Vis spectroscopy was used for characterizing the d–d transitions in the Mn, Co and Ni phosphites.The financial support from Centre National de Recherche Scientifique et Technique (CNRST) (Morocco) (URAC 19). The institutional research plan No. AVOZ10100521 of the Institute of Physics and the grant “Praemium Academiae” of the Academy of Sciences of the Czech Republic

Impact of Preparation Method and Y2O3 Content on the Properties of the YSZ Electrolyte

This study is an effort to cover and interconnect multiple aspects of the fabrication of the yttria-stabilized zirconia (YSZ) from powder preparation to a solid electrolyte suitable for utilization in solid oxide cells. Thus, a series of YSZ electrolytes was prepared, differing in the content of the Y2O3 dopant and in the method of preparation. Combustion synthesis along with the thermal decomposition of precursors was used for YSZ powder synthesis with a dopant content of 8 to 18 mol.%. Post-synthesis treatment of the powder was necessary for achieving satisfactory quality of the subsequent sintering step. The morphology analyses of the YSZ powders and sintered electrolytes produced proved that small particles with a uniform size distribution are essential for obtaining a dense electrolyte. Furthermore, the conductivity of YSZ electrolytes with different Y2O3 contents was examined in the temperature range of 400 to 800 °C. The lowest conductivity was found for the sample with the highest Y2O3 content. The obtained results enable the preparation methods, YSZ powder morphology, and composition to be connected to the mechanical and electrochemical properties of the YSZ electrolyte. Thus, this study links every step of YSZ electrolyte fabrication, which has not been sufficiently clearly described until now

Generalized Poisson--Nernst--Planck-based physical model of O2_2 I LSM I YSZ electrode

The paper presents a generalized Poisson-Nernst-Planck model of an yttria-stabilized zirconia electrolyte developed from first principles of nonequilibrium thermodynamics which allows for spatial resolution of the space charge layer. It takes into account limitations in oxide ion concentrations due to the limited availability of oxygen vacancies. The electrolyte model is coupled with a reaction kinetic model describing the triple phase boundary with electron conducting lanthanum strontium manganite and gaseous phase oxygen. By comparing the outcome of numerical simulations based on different formulations of the kinetic equations with results of EIS and CV measurements we attempt to discern the existence of separate surface lattice sites for oxygen adatoms and O2- from the assumption of shared ones. Furthermore, we discern mass-action kinetics models from exponential kinetics models

Generalized Poisson--Nernst--Planck-based physical model of O2_2 I LSM I YSZ electrode

The paper presents a generalized Poisson-Nernst-Planck model of an yttria-stabilized zirconia electrolyte developed from first principles of nonequilibrium thermodynamics which allows for spatial resolution of the space charge layer. It takes into account limitations in oxide ion concentrations due to the limited availability of oxygen vacancies. The electrolyte model is coupled with a reaction kinetic model describing the triple phase boundary with electron conducting lanthanum strontium manganite and gaseous phase oxygen. By comparing the outcome of numerical simulations based on different formulations of the kinetic equations with results of EIS and CV measurements we attempt to discern the existence of separate surface lattice sites for oxygen adatoms and O2- from the assumption of shared ones. Furthermore, we discern mass-action kinetics models from exponential kinetics models

Crystal structure and spectroscopy studies of the thulium acid pyrophosphate HTmP2O7·3H2O

Crystals of HTmP2O7·3H2O were prepared via a soft chemistry route. Its crystal structure was solved from single-crystal diffraction data. The compound crystallises in the triclinic space group P-1, with the unit cell parameters: a = 6.3724(4) Å, b = 6.8224(3) Å, c = 9.7299(5) Å, α = 82.039(4) °, β = 79.758(5) °, γ = 88.200(4) ° and Z = 2. In its lamellar structure, edge-sharing polyhedra of eightfold coordinated Tm(III) form chains along [010]. These chains are joined in turn to each other using pyrophosphates O-P-O bridges. A network of Osingle bondH…O hydrogen bonds reinforces the cohesion of the structure. The IR spectrum of HTmP2O7·3H2O is interpreted on the basis of characteristic vibrations of PO3 group, POP bridge, and in addition, H2O. The optical properties of HTmP2O7·3H2O were analysed with UV–Vis. The spectrum is characterized by bands corresponding to the transitions starting from the 3H6 ground state to the different higher levels 1G4, 3F2, 3F3, 3H5, and 3F4 of Tm3+ ion