Apatite-type lanthanum silicates attract the attention of scientists due to their high oxygen mobility and, therefore, the opportunity for different applications. The samples of undoped and iron-doped lanthanum silicates with apatite structure were obtained by the modified sol-gel method using beta-cyclodextrin as a template. The precursor decomposition was investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) methods with mass-spectrometry registration of evolved gaseous products. Obtained lanthanum silicates were studied by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX) and low- temperature nitrogen adsorption (BET and BJH). Oxygen mobility in samples was examined with a temperature-programmed isotopic exchange using 18 O 2 and C18O2, which complement each other. The catalytic activity of samples with supported nickel was investigated in the ethanol steam reforming reaction. It was shown that the described synthesis method allows obtaining lanthanum silicates at relatively low temperatures. Synthesized samples have a high oxygen mobility, which increases with iron doping. Also, it was shown that catalyst based on iron-doped lanthanum silicate possesses higher oxygen mobility and catalytic activity than catalysts based on undoped apatites.

The article traces the evolution of the “bird” topos ( murgh ) from its direct understanding ( haqiqa ) to the allegorical (majaz) in the most representative works of the Persian literary tradition of the 10 th –12 th centuries. The research involves methods of philological analysis, as well as the method of historical and philosophical reconstruction of the text. It was found, that in the early samples of the classical qasida by Rudaki and Manuchihri birds were one of the necessary elements for marking the “spring” theme. Later in qasidas of Sanai and Khaqani the topos “soul-bird” ( murgh-i jan ) was firmly entrenched in the poetic dictionary of Persian-speaking Sufis. In the texts of the Brethren of Purity the description of the properties of various animals and birds that entered into an dispute with a person provided the basis for discourse about the properties of the soul. This line was continued by Ahmad al-Ghazzali. In a treatise about bird-souls seeking to find their king, he presented a peculiar description of personal spiritual experience. As a result of the study, author identifies the main themes of the conference of the birds and Sufi concepts that are embodied in specific literary plots.

The author of this article wanted to define a special approach to the problem of how to know God, which developed in the poems of Farid al-Din ‘Attar (1145/46–1221). She based on a comparative analysis of the ‘Attar’s philosophical views with the ideas of the thinkers of Falsafa, Sufism and Isma‘ilism. The author carefully analyzed the prologue named “Concerning the Unity of God” of ‘Attar’s major poem “The Language of the Birds” ( Mantiq al-tayr ). In this prologue ‘Attar deals with theme of “God’s incomparability”, which means the fundamental impossibility of description of God through various categorical combination. The author used the methods of historical and philosophical reconstruction, philological and textological analysis of the text. Particular attention in this article was given to comparison of the theories of the knowledge of God, developed by Ibn Sina, Jalal al-Din Rumi, Mahmud Shabistari, with ‘Attar’s philosophical ideas. The novelty of the research is: for the first time in Russian philosophical Iranian studies ‘Attar’s philosophical views was considered in the context of the general tradition of Arab-Muslim philosophy.

The article deals with investigation of a number of stories about Hasan al-Basri, a great preacher and a major representative of the zuhd movement (‘detachment’) in early Islam. These stories are gathered in anthology ‘Memorial of God’s Friends’ (Tadhkirat al-Awliya’) of the major Persian poet and Sufi thinker of XII–XIII centuries Farid ad-Din ‘Attar Nishaburi. The author provides a brief overview of the ethical ideas of Hasan al-Basri and explores the origins of his ethical doctrine. Hasan al-Basri followed the principle of strict responsibility. He was the forerunner of the Mu‘tazilite doctrine of the autonomy of human will. The focus of the article are the main themes of Hasan al-Basri’s ethical doctrine, such as: longing for higher virtues (sincerity, righteousness, piety, humility), the requirement to follow religious instructions, the overcoming attachments to the mortal world, the critique of wealth and the sermon of asceticism, etc. A detailed analysis of the stories about Hasan al-Basri and his statements allows to conclude, that there numerous ideas in his worldview later will take the form of developed Sufi ethical doctrine. The article shows, that all events from the life of Hasan al-Basri, from his birth to death, should be read and understood in the framework of his spiritual progress along a Sufi path.

Oxygen transport (including oxygen mobility and surface reactivity) is one of the important factors governing electrochemical activity of solid oxide fuel cells electrodes as well as oxygen and hydrogen separation membranes based on materials with mixed oxide-ionic and electronic conductivity. In this work, oxygen mobility data obtained for a series of materials destined for such devices using modern techniques of oxygen isotope heteroexchange are summarized. Series of solid oxide fuel cells’ and membranes’ materials were studied by isotope exchange of their oxygen with 18O2 and C18O2 in isothermal and temperature-programmed modes using closed and flow reactors and data analysis based on developed model of oxygen diffusion and exchange. For solid electrolytes’ materials (Sc- and Ce-doped zirconia) as well as for proton-conducting materials [Ln5.5(Mo,W)O11.25], the effect of composition heterogeneity on the oxygen mobility was demonstrated. For Ln6 – xWO12 – δ, a strong effect of structure on the oxygen mobility was demonstrated. For oxides with asymmetric structure, where oxygen migration proceeds via cooperative mechanisms [La2(Mo,W)2O9, (Ln,Ca)2NiO4], the doping hampers the cooperative migration, resulting in oxygen mobility deterioration and sometimes forming additional slow diffusion channels. In the PrNi0.5Co0.5O3–Ce0.9Y0.1O2 nanocomposites that are materials of the solid oxide fuel cells’ cathode and functional layer of the oxygen separation membranes, two diffusion channels were observed, where more mobile oxygen corresponds to the fluorite phase and interfaces; less mobile, to the perovskite phase. This is due to special features of cations redistribution between the phases.

Design of oxide and nanocomposite materials with high mixed protonic-electronic conductivity such as lanthanide niobates and tungstates is encouraging approach in developing hydrogen separation membranes. This work aims at elucidating the relation of structure, oxygen and protonic mobility of such materials. La0.99Ca0.01NbO4, LaNb3O9 and Nd5.5WO11.25-delta were synthesized by Pechini and citrate route. Nanocomposites with LaNb3O9 and Ni + Cu were prepared by ultrasonic dispersion or mechanical treatment in a high energy mill and wet impregnation, then sintered using conventional thermal sintering and hot pressing. All obtained materials were characterized using XRD, SEM, TEM with EDX analysis, IR and Raman spectroscopy. The oxygen and proton mobility were studied by isotope exchange, unit cell volume and weight relaxation techniques. The proton conductivity was studied by Van der Pauw technique. The main phases were scheelite for La0.99Ca0.01NbO4, perovskite for LaNb3O9 and fluorite for Nd5.5WO11.25-delta, extended defects were observed agreeing with IR and Raman spectroscopy data. The oxygen mobility studies revealed two types of bulk oxygen related to two phases in samples. D2O exchange studies demonstrated very fast protonic transport in samples. H2O desorption experiments revealed the working temperature range being 300-450 degrees C. The protonic conductivity values (similar to 10(-4) Omega(-1) cm(-1) at 400 degrees C) agree with the literature data and are sufficiently high for the practical application. Proton tracer and chemical diffusion coefficients values are similar to 10(-11) and similar to 10(-3) cm(2)/s at working temperatures, respectively. Successful test of proton conducting membrane with Nd5.5WO11.25-delta based functional layer showing promising performance has been carried out.

The article deals with investigation of a number of stories about the conversations between Rabi‘ a al-‘Adawiya and Hasan al-Basri, representatives of the early mystical and ascetic trend in Islam. These stories are gathered in poems of the major Persian poet and Sufi thinker of XII — XIII centuries Farid ad-Din ‘Attar (“The Language of the Birds”, “The Divine Book”) and anthology “Memorial of God’s Friends”). The article shows, that Rabi‘a was consistently developing the idea, that it is impossible to the Sufi to attain higher moral qualities or true knowledge, if he tries to build a relationship with God striving for his own posthumous felicity and award. That is why in his poems and anthology, ‘Attar affi rms that Rabi‘a’s highest spiritual qualities and divine knowledge are fruit of her pure love to God, and not of her desire for the happy afterlife. The conversations between Rabi‘a al-‘Adawiya and Hasan al-Basri represent a very rare occurrence in Islamic culture, when a woman, (because of her righteousness and full concentration on love to God), could become a spiritual guide for great Sufi men at that time. Later her life was considered by the Sufi traditionas an example to be followed for those who had chosen the Sufi path of God’s knowledge. The article examines the most important aspects of Rabi‘ a’s teachings in the context of the philosophical views of ‘Attar. The certain aspects of Rabi‘a’s Sufi conversation are discussion of Sufi virtues, of intuitive knowledge and human love for God. In Rabi‘a’s teachings the love of God and recognition of His unity and uniqueness (tawhid) appears as the unique way to the reaching the inner spiritual integrity.

The key problems in developing catalytic membranes for producing syngas from biofuels by selective oxidation with oxygen separated from air are design of materials for functional layers and optimization of techniques of their deposition. Nanocomposite materials based upon praseodymium nickelate-cobaltite are promising for these purposes due to their high oxygen mobility provided by the fast oxygen diffusion channel. The oxygen permeability of membrane obtained meets criteria of the practical application. Syngas yield and methane conversion increase with temperature and contact time. Stable performance of the membrane was demonstrated for at least 200h time-on-stream.

Co-doped praseodymium nickelates PrNi1−xCoxO3−δ and their composites with yttrium doped ceria Ce0.9Y0.1O2−δ are known to be promising materials for intermediate temperature solid oxide fuel cells and membranes for oxygen separation. Powdered samples were obtained via Pechini route and ultrasonic dispersion followed by mechanical activation. Pellets were sintered at 870–1100°C by using microwave radiation. In comparison with conventionally sintered materials, the phase transition leading to Ruddlesden–Popper phase formation was shifted down for about 50°C–100°C. The effect of sintering by microwave radiation consisted of dramatically increased sample density, improved phase purity and enhanced oxygen mobility. When undesirable phase transitions at elevated sintering temperatures hinder gas-tight layers preparation, the microwave sintering technique can be used without any deterioration of transport properties of materials in comparison with conventional calcination.

This work summarizes results of synchrotron radiation (SR) studies of the real/defect structure of nanocrystalline/nanocomposite oxide materials, which determines their functional properties in hydrogen energy field as catalysts and mixed ionic electronic conductors (cathodes and anodes of solid oxide fuel cells, oxygen separation membranes). For nanocrystalline ceria-zirconia mixed oxide prepared via modified Pechini route using ethanol solution of reagents, a high spatial uniformity of cations distribution between domains along with the oxygen sublattice deficiency revealed by full-profile Rietveld refinement of SR diffraction data provide structure disordering enhancing oxygen mobility. For PrNi0.5Co0.5O3–δ – Ce0.9Y0.1O2–δ nanocomposite extensive transfer of Pr cations into fluorite domains generates a new path of fast oxygen diffusion along chains of Pr3+ – Pr4+ cations as directly proved by analysis of the unit cell relaxation after changing pO2 in perfect agreement with data obtained by oxygen isotope heteroexchange.

This work aims at elucidating effects composition and microstructure of materials based upon Pr1-ySmyNi1-xCoxO3-delta per ovskites on their oxygen mobility. Pr1-ySmyNi1-xCoxO3-delta and their omposites with Y-doped ceria are perspective materials for inter mediate temperature solid oxide fuel cells and oxygen separation branes. Doping Pr1-ySmyNi1-xCoxO3-delta by Sm results in suppression o the fast channel of oxygen diffusion along extended defects due o Sm segregation in their vicinity For nanocomposites moderate doping by Sm enhances fast oxygen diffusion in fluorite phase domains and along perovskite-fluorite interface due to a higher disordering caused by incorporation of both Pr arid Sm cations into Y-doped ceria.

A unique combination of methods (TPD of O2, thermogravimetry, isotopic heteroexchange of oxygen in different modes) was used to carry out detailed studies of oxygen mobility and reactivity in mixed praseodymium nickelates-cobaltites (PrNi1 − x Co x O3 + δ) and their composites with doped cerium dioxide (Ce0.9Y0.1O2 − δ) as promising cathodic materials stable towards the effect of CO2 in the intermediate-temperature region. It is shown that in the case of composites of PrNi1 − x Co x O3+δ-Ce0.9Y0.1O2 − δ synthesized using the Pechini method and ultrasonic treatment, stabilization of the disordered cubic perovskite phase due to redistribution of cations between the phases provides high oxygen mobility. Preliminary results on tests of cathodic materials of this type supported on planar NiO/YSZ anodes (H.C. Starck) with a thin layer of YSZ electrolyte and a buffer Ce0.9Y0.1O2 − δ layer showed that power density of up to 0.4 W/cm2 was reached in the region of medium (600–700°C) temperatures, which was close to typical values for fuel cells of this type with cathodes based on strontium-doped perovskites and their composites with electrolytes.

An approach was developed towards design of medium-temperature solid-oxide fuel cells based on a deformation strengthened Ni-Al alloy. Methods of sintering were described that allowed obtaining layers of complex oxides with ionic and mixed conductivity and with regulated porosity in the range of 40–1%. Power density of a fuel cell on a metallic support reaches 500 mW/cm2 already at 700°C when humid H2 was used as fuel and air was used as an oxidant. Analysis of fuel cell cross-section after tests showed absence of fractures, flaking, and new phases with low conductivity, which proves good compatibility of all materials used in fuel cell design.