I. V. Zatovsky

Hierarchical NiCoP nanocone arrays supported on Ni foam as an efficient and stable bifunctional electrocatalyst for overall water splitting

Design of cost-effective, highly efficient and stable bifunctional electrocatalysts for overall water splitting is necessary for renewable energy systems. In this study, NiCoP nanowire arrays grown on 3D Ni foam (NiCoP NWAs/NF) were successfully synthesized by a two-step method, which were developed as novel bifunctional electrocatalysts for evaluating in the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Their special cone nanostructure and bifunctional crystal structure enable the electrocatalysts to display remarkable electrocatalytic performance and stability for OER and HER (maintained for 28 h in the long-term HER and OER stability test with slight attenuation). The electrodes have very low overpotentials of 197 mV and 370 mV for HER and OER in 1.0 M KOH at a high current density of 100 mA cm−2, respectively. All the merits can be attributed to several parameters: the inherent nature of transition metal phosphides, the presence of a bimetal synergetic effect, special morphology design, and the formation of “secondary” electrocatalysts on the surface of NiCoP. Meanwhile, the excellent bifunctional electrocatalysts can be developed as both anode and cathode of an alkaline electrolyzer (1.0 M KOH) which needs a cell voltage of 1.64 V to achieve 20 mA cm−2 current density.

Crystallization from Na2O-P2O5-Fe2O3-MIIO (MII = Mg, Ni) melts and the structure of Na4MgFe(PO4)3

We have studied general trends of phosphate crystallization from Na2O-P2O5-Fe2O3-MIIO (MII = Mg, Ni) high-temperature solutions at Na/P = 1.0−1.4, MII/Fe = 1.0, and Fe/P = 0.15 or 0.3, and identified the stability regions of the phosphates Na4MIIFe(PO4)3 (MII = Mg, Ni), NaFeP2O7, and Na2NiP2O7. The synthesized compounds have been characterized by X-ray powder diffraction and infrared spectroscopy. The structure of Na4MgFe(PO4)3 (sp. gr.

Phase relations in M2IO-P2O5-Fe2O3-CaO(CaF2) (MI = Na, K) high-temperature solutions and the structure of Na2.5CaFe1.5(PO4)3

Rbar 3c

Synthesis and characterization of phosphates in the pseudo‐ternary melted systems Cs2O‐P2O5‐MIIO (MII – alkaline earth)

, a = 8.83954(13) Å, c = 21.4683(4) Å) has been determined by Rietveld powder diffraction analysis.

Crystal growth of zirconium‐doped KTiOPO4 crystals in the K2O‐P2O5‐TiO2‐ZrF4 system

The single crystals of langbeinite-related K2BiZr(PO4)3 have been obtained for the first time by spontaneous crystallization method from K-Zr-P-O-F molten system. The compound crystallizes in a space group P213 with cell parameter a = 10.30360 Å. The framework is built up from isolated Bi/ZrO6 octahedra connected together by PO4 units. For the two K+ cations two types of oxygen coordination numbers 9 and 12 are observed. The photoluminescence (PL) spectroscopy studies of K2BiZr(PO4)3 are carried out under the VUV synchrotron excitations. The electronic structure of K2BiZr(PO4)3 crystal is calculated by the FLAPW method. The PL spectra reveal two main components in the UV and visible spectral regions (peaking near 3.6 and 2.7 eV respectively). It is assumed that the UV PL component of K2BiZr(PO4)3 originates from transitions in ZrO6 polyhedra, while the visible one is related to Bi3+ ions in oxygen coordination.

New complex phosphates Cs3MIIBi(P2O7)2 (MII – Ca, Sr and Pb): synthesis, characterization, crystal and electronic structure

Phase relations in high-temperature solutions of the M2IO-P2O5-Fe2O3-CaO(CaF2) (MI = Na, K) systems (M2IO/P2O5 = 0.7, 1.0, 1.3; Ca/P = 0.3; Ca/Fe = 1.0; Δt = 1000–680°C) have been studied. The nature of the calcium precursor has been shown to influence the phase relations in the multicomponent alkali metal phosphate high-temperature solutions. The synthesized compounds have been characterized by X-ray powder diffraction and IR spectroscopy, and the crystal structure of the new phosphate Na2.5CaFe1.5(PO4)3 has been determined by single-crystal X-ray structure analysis.

Diversity of POM-based Copper Compounds Obtained from the Same Reaction System

Abstract The interaction of TiN with Na2O–K2O–P2O5 melts was investigated at (Na+K)/P molar ratios of 0.9, 1.0, and 1.2 and at Na/K molar ratios of 1.0 and 2.0. Interactions in the system led to the loss of nitrogen and the partial loss of phosphorus and resulted in the formation of KTiP2O7 and langbeinite‐type K2−xNaxTi2(PO4)3 (x=0.22–0.26) solid solutions over the temperature range of 1173 to 1053u2005K. The phase compositions of the obtained samples were determined by using X‐ray diffraction (including Rietveld refinement), scanning electron microscopy (using energy‐dispersive X‐ray spectroscopy and element mapping), FTIR spectroscopy, and thermogravimetric analysis/differential thermal analysis. K1.75Na0.25Ti2(PO4)3 was characterized by single‐crystal X‐ray diffraction [P213 space group, a=9.851(5)u2005Å]. The 3D framework is built up by TiO6 octahedra and PO4 tetrahedra sharing all the oxygen vertices with the formation of cavities occupied by K(Na) cations. Only one of the two crystallographically inequivalent potassium sites is partially substituted by sodium, and this was confirmed by calculating the bond‐valence sum. The thermodynamic stability of K1.75Na0.25Ti2(PO4)3 crystals and the preferable occupation sites of NaK cationic substitutions were investigated by DFT‐based electronic structure calculations performed by the plane‐wave pseudopotential method.