Highly Proton-Conductive Zinc Metal-Organic Framework Based On Nickel(II) Porphyrinylphosphonate

The design of new solid-state proton-conducting materials is a great challenge for chemistry and materials science. Herein, a new anionic porphyrinylphosphonate-based MOF ( IPCE-1Ni ), which involves dimethylammonium (DMA) cations for charge compensation, is reported. As a result of its unique structure, IPCE-1Ni exhibits one of the highest value of the proton conductivity among reported proton-conducting MOF materials based on porphyrins (1.55×10⁻³ S cm⁻¹ at 75 °C and 80 % relative humidity).     

Na3V2(PO4)3/C/Ag nanocomposite materials for Na-ion batteries obtained by the modified Pechini method

Journal of Solid State Electrochemistry - Nanocomposite materials, Na3V2(PO4)3/C and Na3V2(PO4)3/C/Ag, were synthesized by a modified Pechini method. Their properties were characterized with the...     

Synthesis and Ionic Conductivity of LiZr2(VO4)x(PO4)3 – x

Russian Journal of Electrochemistry - Vanadate phosphates LiZr2(VO4)x(PO4)3 – x are synthesized by the sol-gel technique with subsequent annealing and studied using X-ray diffraction...     

Detonation nanodiamonds as catalysts of steam reforming of ethanol

Physicochemical properties and catalytic performance of detonation nanodiamonds were studied. Original samples of nanodiamonds and nanodiamonds modified by hydrogen, oxygen, and nitric acid with hydrogen peroxide and infrared-treated were investigated. The catalyst structure and morphology were examined by transmission electron microscopy and IR spectroscopy. All the investigated catalysts were active in the steam reforming of ethanol. The correlation of catalytic properties with composition and structure of the described systems is discussed. The specific surface area of nanodiamonds is changed insignificantly upon modification.     

Effect of modification of the MF-4SC membranes in the potassium form with acid salts of heteropolyacids on membrane properties and characteristics of dp sensors based on them

Hybrid materials based on perfluorinated sulfo cation-exchange MF-4SC membrane and nanoparticles of cesium hydrogen phosphotungstate and silicotungstate heteropolyanions were obtained. These membranes with a gradual dopant distribution along the length were used to develop potentiometric sensors for determination of amino-containing organic cations in aqueous solutions at pH < 7. A relationship between the membrane transport characteristics and sensing properties was elucidated.     

Short- and long-range order balance in nanocrystalline Gd2Zr2O7 powders with a fluorite-pyrochlore structure

A series of nanocrystalline Gd₂Zr₂O₇ powders has been studied using a combination of X-ray diffraction and X-ray spectroscopy with synchrotron radiation. It has been shown that isothermal annealing of an X-ray amorphous mixed hydroxide first leads to the formation of an oxide nanomaterial with a defect fluorite structure and clearly pronounced nonequivalence of the local environment of the Gd³⁺ and Zr⁴⁺ ions. Increasing heat treatment temperature results in initiation and growth of nanodomains with pyrochlore-type superstructure ordering of cations inside bulkier crystallites of defect fluorite. To adequately describe the evolution of the real nanocrystalline structure of gadolinium zirconate, a combination of X-ray structural methods sensitive to the averaged crystal structure and local atomic structure should be used.     

Cathodes based on (La,Sr)MnO<Subscript>3</Subscript> modified with PrO<Subscript>2 − <Emphasis Type="Italic">x</Emphasis></Subscript>

The electrochemical characteristics of composite cathodes made of (La, Sr) MnO₃-(Zr, Sc)O₂ (LSM-SSZ), modified with PrO_{2 − x} additive, and designed for application in solid oxide fuel cells at moderately high temperatures were studied. The relationship between activity of catalytically modified composite LSM-SSZ cathodes and dispersity of electrocatalyst was revealed. The boundaries of the temperature range with the maximum dispersity of electrocatalyst and electrochemical activity of cathodes were found. The composite LSM-SSZ cathodes modified with PrO_{2 − x} were shown inert with respect to oxidation reactions of hydrocarbon fuel (methane) and highly active electrochemically with respect to oxygen reaction in non-equilibrium gas mixture of CH₄ and O₂. In cells with (Ce, Sm)O₂ (SDC) and (Zr, Y)O₂ (YSZ) electrolytes, their overvoltage is below 80 mV at the current density about 0.5 A/cm² and temperature of 600°C. These electrodes can be used as cathodes in single-chamber fuel cells. Long-term experiments were carried out to study time stability of characteristics of the said composite cathodes. The studied electrodes show parabolic or damped exponential time curves of polarization resistance if contacting with YSZ or SDC electrolyte, respectively. According to the forecast based on the experimental regularities, the polarization resistance of LSM-SSZ cathodes in 10,000 h will not exceed 0.4 or 0.13 Ohm cm², respectively, if YSZ or SDC electrolyte is used.