V. A. Sadykov

• Professor
• Head of Department at Boreskov Institute of Catalysis

La tungstates possessing a high protonic conductivity (~10-4 S/cm at 600 °C) are state-of-the-art materials for hydrogen separation membranes. A promising approach in design of new materials for this application is creation of triple-conductive materials on their basis. The current work aims at studying structural, textural and transport properties...

Mesoporous MgAl2O4 + LnFe0.7Ni0.3O3 (Ln = La, Pr) nanocomposites were prepared by a cost-effective one-pot procedure with the Pluronic P123 copolymer and Ni + Ru active components were supported on them by wet impregnation. The real structure of samples was studied by X-ray diffraction and transmission electron microscopy with energy-dispersive X-r...

The ever-increasing energy consumption and dwindling fossil resource reserves, progressive global warming and the resulting deterioration of the environment have led to intensive development of research in the field of more advanced alternative energy sources. One of the directions in which the energy sector is moving towards a "green" economy is t...

Recent directions concerning hydrogen production, storage and utilization result in growing the demand for efficient technologies, a huge part of which is connected with the application of materials based on complex oxides as efficient catalysts for the fuel reforming, permselective membranes, components of solid oxide fuel cells and electrolyzers....

This study aims at investigating oxygen content and diffusion in the Pr1.6Ca0.4Ni1‑yCuyO4+δ (y = 0.0–0.4) series. Single-phased materials were obtained via nitrate combustion using glycerol as a fuel. The materials exhibit an orthorhombic structure, which correlates well with the absolute oxygen content in the samples in the range of 4.15–3.97. The...

Production of syngas by methods alternative to steam reforming of methane now becomes more popular due to both environmental and commercial reasons. Transformation of oxygenates obtained from biomass and dry reforming of natural gas appears to be the most effective. This review considers problems related to the design of efficient structured cataly...

Layered nickelates, as representatives of Ruddlesden-Popper phases, are widely used in electrochemical, catalytic and other applications due to their advanced transport and thermomechanical characteristics. In this work, La2–xSmxNiO4+δ (x = 0.0 – 1.0) complex oxides are obtained and then comprehensively studied as potential oxygen electrode materia...

Oxygen and hydrogen mobility are among the important characteristics for the operation of solid oxide fuel cells, permselective membranes and many other electrochemical devices. This, along with other characteristics, enables a high-power density in solid oxide fuel cells due to reducing the electrolyte resistance and enabling the electrode process...

Oxygen and hydrogen mobility are among the important characteristics for operation of solid oxide fuel cells, permselective membranes and many other electrochemical devices. This, along with other characteristics, enables reaching a high power density of solid oxide fuel cells and a high oxygen or hydrogen permeation fluxes for membranes. This work...

Mesoporous MgAl2O4 support is promising for design of efficient and stable to coking catalysts of natural gas and biofuels reforming into syngas. This work aims at doping this support with...

This paper is devoted to the study of active and stable nickel catalysts for methane dry reforming based on Pr-doped ceria–zirconia obtained via the solvothermal continuous method. Studies on the physicochemical and catalytic properties of the 5%Ni/Ce0.75Zr0.25−xPrxO2 series have showed that Pr introduction leads to an increase in the amount of hig...

Synthesis and study of materials based on bismuth cerates and titanates were carried out. Complex oxides Bi1.6Y0.4Ti2O7 were synthesized by the citrate route; Bi2Ce2O7 and Bi1.6Y0.4Ce2O7—by the Pechini method. The structural characteristics of materials after conventional sintering at 500–1300 °C were studied. It is demonstrated that the formation...

A series of 5%Ni/Ce1-xTixO2 catalysts was prepared with nickel impregnation of mixed Ce–Ti oxides obtained via synthesis in supercritical isopropanol. All oxides have a cubic fluorite phase structure. Ti is incorporated into the fluorite structure. Small amounts of impurities of TiO2 or mixed Ce–Ti oxides appear with Ti introduction. Supported Ni i...

This work is devoted to the study of active and stable nickel catalysts for methane dry reforming based on Pr-doped ceria-zirconia obtained by solvothermal continuous method. The studies of physicochemical and catalytic properties of the 5%Ni\Ce0.75Zr0.25-xPrxO2 series showed that Pr introduction leads to an increase in the amount of highly reactiv...

Mixed Ce−Zr oxides with a fluorite structure were synthesized by the solvothermal method in a supercritical medium of isopropanol. The prepared mixed oxides Ce0.5Zr0.5O2 and Ce0.75Zr0.25O2 were used as supports for 5 wt%Ni and bimetallic 2.5 wt%Ni+2.5 wt%Co catalysts. The catalysts were fully characterized (specific surface area, morphology, partic...

The Ruddlesden‒Popper phases pertain to numerous promising materials with the mixed ionic-electronic conductivity used in devices such as oxygen-conducting membranes, solid oxide fuel cells (SOFC), and electrolyzers, which operate in the intermediate temperature region. Their high total conductivity and oxygen mobility make these materials candidat...

To solve problems related to global warming, environmental pollution, and green energy fields, a lot of research is now devoted to the catalysis of biofuels and biogas transformation into syngas and hydrogen [...]

Single-phase Ce–Zr oxides with a fluorite structure were synthesized by the solvothermal method in an isopropanol medium. Synthesis was performed at the supercritical parameters of isopropanol. The effect of the synthesis parameters on the characteristics of the obtained materials (specific surface area, morphology, particle size, phase composition...

The Ruddlesden‒Popper phases pertain to numerous promising materials with the mixed ionic-electronic conductivity used in devices such as oxygen-conducting membranes, solid oxide fuel cells (SOFC), and electrolyzers, which operate in the intermediate temperature region. Their high total conductivity and oxygen mobility make these materials candidat...

Two series of Ni/Ce(Ti/Nb)ZrO2 catalysts were prepared using citrate route and original solvothermal continuous flow synthesis in supercritical isopropanol and studied in dry reforming of methane (DRM). TEM, XPS and FTIRS of adsorbed CO confirm influence of support composition and preparation method on the catalysts’ morphology and surface features...

Modern hydrogen energy technologies include generation of syngas and pure hydrogen from biofuels to be used for green energy production in solid oxide fuel cells (SOFC). To be economically feasible, these processes require design of stable, efficient and inexpensive catalysts, permselective membranes for hydrogen and oxygen separation as well as SO...

Catalysts based on perovskite—fluorite nanocomposites with supported nickel 5%Ni/[Pr0.15Sm0.15Ce0.35Zr0.35O2 + LaMn0.9Ru0.1O3] were synthesized by three different methods. Structural and surface features of as-prepared samples were elucidated by N2 adsorption, XRD, HR TEM with EDX; reducibility and reactivity were estimated by H2-TPR, and catalytic...

Lanthanide tungstates and molybdates are promising materials for hydrogen separation membranes due to their high protonic conductivity. A promising approach to fabricating ceramics based on these materials is radiation thermal sintering. The current work aims at studying the effect of radiation thermal sintering on the structural morphological and...

Orthoniobates of rare-earth elements are a promising group of materials attractive for the design of nanocomposite hydrogen separation membranes owing to a perspective type of proton conductivity, good mechanical properties, and high stability in H2O- and CO2-containing atmospheres. In general, the promising method involves the synthesis of nanocom...

Membrane reactors (MR) with an appropriate catalyst are considered to be an innovative and intensified technology for converting a fuel into the hydrogen-rich gas with the simultaneous recovery of high-quality hydrogen. Characteristics of an asymmetric membrane disk module consisting of a gas-tight nanocomposite functional coating (Ni + Cu/Nd5.5WO1...

This study is aimed at studying the properties of La2NiO4+δ (LNO) substituted with rare earth elements to increase its oxygen over-stoichiometry and enhance oxygen transport thus improving electrochemical properties of the related electrodes. Materials of the La1.6Ln0.4NiO4+δ series (where Ln = Pr (LPNO), Nd (LNNO), Sm (LSNO), Eu (LENO), Gd (LGNO))...

Nd tungstates and molybdates are promising materials for hydrogen separation membranes due to their high protonic conductivity. This work aims at elucidating the structural, textural and oxygen transport features of Nd5.5WO11.25-δ, Nd5.5W0.5Mo0.5O11.25-δ and (Nd5/6La1/6)5.5WO11.25-δ and their composites with Ni0.5Cu0.5O synthesized by mechanical ac...

Featured Application Extended experimental data obtained in the framework of this study on the structure, high-temperature behavior, oxygen diffusion, and electrode performance of the Nd1.6Ca0.4Ni1−yCuyO4+δ materials are a solid base for their future practical application as air electrodes, membranes for oxygen production and catalytic membranes. D...

In the present work, complex powder alloys containing spinel as a minor phase were produced by mechanical alloying in a high-energy planetary ball mill from a 33Al–45Cu–22Fe (at.%) powder blend. These alloys show characteristics suitable for the synthesis of promising catalysts. The alloying was conducted in two stages: at the first stage, a Cu+Fe...

The present study deals with the combination of ethanol steam reforming over a monolithic catalyst and hydrogen separation by membrane in a lab-scale catalytic membrane reactor (CMR). The catalyst was comprised of honeycomb thin-walled Fechralloy substrate loaded with Ni + Ru/Pr0.35Ce0.35Zr0.35O2 active component. The asymmetric supported membrane...

This issue will deal with new approaches to the design of asymmetric supported membranes for oxygen and hydrogen separation based on fundamental studies of the structural/transport properties of mixed ionic-electronic conducting nanocomposites and these materials supporting as the functionally graded layers on robust macroporous/foam substrates. Di...

This review considers problems related to design of efficient structured catalysts for natural gas and biofuels transformation into syngas. Their active components are comprised of fluorite, perovskite and spinel oxides or their nanocomposites (both bulk and supported on high surface area Mg-doped alumina or MgAl2O4) promoted by platinum group meta...

Advances in design of materials for solid oxide fuel cells, oxygen and hydrogen separation membranes and catalysts for biofuels conversion into syngas and hydrogen are reviewed. Application of new efficient techniques of materials synthesis and characterization of their atomic-scale structure, transport properties and reactivity allowed to develop...

In this work complex metal-oxide catalysts with the general formula 5 wt% Ni/Ce0·75Zr0.25-x(Nb,Ti)xO2-δ were synthesized by the solvothermal method using supercritical alcohols followed by nickel deposition. The catalysts were characterized and studied in ethanol dry reforming reaction (EDR) in the temperature range 600–750 °C. XRD and TEM showed t...

Invitation to submit papers to special issue of Energies: hydrogen and syngas generation

Ethanol steam reforming catalyst’s precursors, i.e., nanocomposites of complex oxides with the general formula [Pr0.15Sm0.15Ce0.35Zr0.35O2 + LaMn0.45Ni0.45Ru0.1O3] (1:1 by mass), were synthesized by three different methods. It was shown that two synthesis methods – ultrasonic dispersion and sequential polymeric method, lead to the formation of the...

Producing syngas and hydrogen from biofuels is a promising technology in the modern energy. In this work results of authors’ research aimed at design of supported membranes for oxygen and hydrogen separation are reviewed. Nanocomposites were deposited as thin layers on Ni–Al foam substrates. Oxygen separation membranes were tested in CH4 selective...

The Ni-containing catalysts based on ceria–zirconia doped with Ti and Ti+Nb were prepared by the solvothermal method in supercritical fluids. Ni deposition was carried out by incipient wetness impregnation and the one-pot technique. All materials were investigated by a complex of physicochemical methods (XRD, BET, TEM, H2-TPR). Samples catalytic pr...

The performance of catalytic membrane reactors (CMRs) depends on the specific details of interactions at different levels between catalytic and separation parts. A clear understanding of decisive factors affecting their operational parameters can be provided via mathematical simulations. In the present paper, main results of numerical studies of et...

Composites comprising MoVTeNbO mixed oxide and zirconia-pillared montmorillonite clays (PilCs) were prepared. XRD and TEM with EDX studies confirmed the preservation of M1 MoVTeNbO phase in these composites responsible for high activity and selectivity in ethane oxidative dehydrogenation into ethylene. For composites with PilC content of 10 wt%, th...

For catalysts comprised of mixed manganese-chromium oxides MnxCr3-xO4 (x = 0.3–2.7) prepared by Pechini route with Ni and Ru supported by impregnation fundamental factors determining their performance in ethanol steam reforming have been elucidated using combination of structural (XRD, HRTEM), spectroscopic (UV–vis), surface science (XPS, FTIR spec...

In this study the bilayer composite electrodes based on LaNi0.6Fe0.4O3-d (LNF) electronic conductor and Bi2O3-based electrolytes doped with Er (Bi1.6Er0.4O3, EDB) and Y (Bi1.5Y0.5O3, YDB) have been developed and their performance has been investigated in the dependence on the electrolyte content and sintering conditions. The polarization resistance...

This work presents the results from a study of the structure and transport properties of Ca-doped La2NiO4+δ. La2−xCaxNiO4+δ (x = 0-0.4) materials that were synthesized via combustion of organic-nitrate precursors and characterized by X-ray diffraction (XRD), in situ XRD using synchrotron radiation, thermogravimetric analysis (TGA) and isotope excha...

In the present work erbium and thulium molybdates Ln5.5MoO11.25−δ (Ln = Er and Tm) with fluorite and Ln6MoO12−δ (Ln = Er and Tm) with bixbyite structure have been studied. The materials have been obtained by mechanical activation method followed by sintering at 1600°С for 3 h. New compounds have been characterized by X-ray diffraction. The total co...

Ordered mesoporous MgAl2O4 support was synthesized by one-pot evaporation-induced self-assembly method with block copolymers. Nanocomposite catalysts were prepared by loading this support with PrNi0.9Ru0.1O3 perovskite or Ni + Ru-doped Ce0.35Zr0.35Pr0.3O2 fluorite oxides. Their texture, structure, surface properties and reactivity have been studied...

In this work new RP materials of the La2-xGdxNiO4+δ series were synthesized and their structural features, oxygen stoichiometry and transport properties were studied by X-ray diffraction, TGA, mass relaxation method and oxygen isotope exchange with C18O2 in a flow reactor. According to XRD data, La2-xGdxNiO4+δ (x = 0.0; 0.2; 0.4) are single-phase s...

In the field of modern hydrogen energy, obtaining pure hydrogen and syngas and then being able to use them for green energy production are significant problems. Developing solid oxide fuel cells (SOFC) and catalytic membranes for oxygen separation as well as materials for these devices is one of the most likely ways to solve these problems. In this...

Oxides with pyrochlore structure are promising materials for SOFCs, oxygen and hydrogen separation membranes, and other devices. Ln zirconates attract interest due to their oxygen and protonic mobility. In this work, oxygen transport mechanism in Mg-doped Sm and Gd zirconates was studied. Sm1.9Mg0.1Zr2O6.95 and Gd1.9Mg0.1Zr2O6.95 oxides have been p...

Enhanced activity in low-temperature water-gas shift (LT-WGS) reaction of some ceramometal catalysts compared to conventional Cu-Zn-Al oxide catalyst was demonstrated. Porous ceramometals were synthesized from powdered CuAl alloys prepared by mechanical alloying with the addition of either CuAlexp powders produced by current spark explosion of Cu+A...

A series of 5%Ni-CexZr1−xO2 (x = 0.3, 0.5, 0.7) catalysts has been prepared via one-pot solvothermal continuous synthesis in supercritical isopropanol and incipient wetness impregnation of CexZr1−xO2 obtained by the same route. The textural, structural, red-ox, and catalytic properties in methane dry reforming (MDR) of Ni-modified Ce-Zr oxides synt...

To achieve a high activity and coking stability of nickel catalysts in dry reforming of methane, materials comprised of ceria–zirconia doped by Ti were investigated as supports. Ceria–zirconia supports doped with titanium were prepared either via the Pechini method or by synthesis in supercritical alcohol media. Ni-containing catalysts were prepare...

A-site deficient Ruddlesden–Popper phases now attract a lot of attention as promising materials for intermediate temperature solid oxide fuel cells' cathodes and oxygen separation membranes. However, controversial information on the A-site deficiency effect on structural, transport and electrochemical properties of these materials apparently requir...

Nickel-containing mixed ceria-zirconia oxides also doped by Nb and Ti have been prepared by a citrate route and by original solvothermal continuous flow synthesis in supercritical alcohols. Nickel was subsequently deposited by conventional insipient wetness impregnation. The oxides are comprised of ceria-zirconia solid solution with cubic fluorite...

LaCoO 3 samples were obtained by the hydrothermal and citrate methods. The dynamics of the phase transformations of the initial hydroxo compounds into the oxide state and the subsequent reduction in a hydrogen-containing mixture were studied by the differential thermal analysis and X-ray diffraction methods. The results of the catalytic tests in th...

Design of oxygen and hydrogen separation membranes is the point of current interest in producing syngas from biofuels. Nanocomposites with a high mixed ionic-electronic conductivity are known to be promising materials for these applications. This work aims at studying performance of oxygen and hydrogen separation membranes based on nanocomposites P...

Сatalyst precursors, substituted by rare-earth and transition metals, promoted with Ru nanoparticles using the modified Pechinimethod (Organic polymeric precursor) have been synthesized. To transform biofuel (ethanol) into hydrogen from the obtained active phases, three different methods were used to synthesize composites with the general formula [...

Novel methods were applied in this work to elucidate the structure evolution of Ln2-xCaxNiO4+δ oxides (Ln = La, Pr, Nd; x = 0, 0.3) and study their oxygen mobility. Relationship between cations state, structural, electrical, electrochemical and kinetic properties was revealed. In all doped materials the overall oxygen mobility characterized by Do d...

The nanostructured CexZr1-xO2 systems (0 ≤ x ≤ 0.75) were prepared combining alkoxide and nitrate precursors in an ethanol/water mixture by the continuous supercritical solvothermal sol-gel like synthesis. They were subsequently used as supports for nickel impregnation (10 wt.%) to obtain catalysts for dry reforming of methane (DRM) reaction. A ref...

For La2Zr2O7/LaAlO3 composite prepared by aging (100 °C/10 h) of the mixture of precipitated precursors of La-Zr-O and La-Al-O, evolution of its structural features after sintering in air in the range of 100–1300 °C was investigated by applying XRD, HRTEM, FTIR, Raman and UV–Vis spectroscopies, ²⁷Al MAS NMR and ¹³⁹La NMR. The initial composite form...

The Guest Editors are inviting submissions to a Special Issue of Energies, titled “Hydrogen and Syngas Generation”.

Mechanism of ethanol partial oxidation into syngas over catalysts based on mesoporous MgAl2O4 spinel loaded with fluorite PrCeZrO or spinel MnCr2O4 oxides and promoted by Ru + Ni was studied by in situ FTIRS and 18O SSITKA. Surface species (ethoxy, adsorbed ethanol, acetaldehyde, acetate, etc.) were identified and their thermal stability and reacti...

Ln molybdates are promising materials for hydrogen/oxygen separation membranes. This work aims at elucidating features of oxygen transport in Ln10Mo2O21 (Ln = Nd, Ho) oxides using novel 2D diffusion models. Nd10Mo2O21 and Ho10Mo2O21 were synthesized by the mechanical activation followed by sintering in the 1600–1650 °C temperature range and charact...

Pr2NiO4+δ oxide with a layered Ruddlesden–Popper structure is a promising material for SOFC cathodes and oxygen separation membranes due to a high oxygen mobility provided by the cooperative mechanism of oxygen migration involving both interstitial oxygen species and apical oxygen of the NiO6 octahedra. Doping by Ca improves thermodynamic stability...

This review considers the problems associated with the development and operation of highly active and stable structured catalysts for biogas/biofuel conversion into syngas and hydrogen based on nanocrystalline oxides with fluorite, perovskite, and spinel structures and their nanocomposites promoted by nanoparticles of platinum group metals and allo...

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 serie...

Novel stable to carbonization nanocomposite materials based upon Pr2-xNiO4+δ, Pr1-xSmxNi1-yCoyO3-δ and YDC were synthesized via Pechini route and ultrasonic dispersion, sintered using conventional and advanced (microwave, e-beam) techniques. Their real/nano structure and transport properties were characterized by sophisticated methods. Nanocomposit...

Mixed ionic-electronic conductors are of great interest for development of oxygen separation membranes and air electrodes for intermediate temperature solid oxide fuel and electrolysis cells. This work presents the results of studying the structure, transport properties and oxygen mobility in Nd2−xCaxNiO4 oxides (x=0–0.5), synthesized via a solutio...

Materials with a layered Ruddlesden–Popper structure having high oxygen mobility are promising for SOFC cathodes and oxygen separation membranes. This work aims at studying structural and transport features of Pr2-xCaxNiO4+δ (x = 0–0.6) oxides synthesized by a modified co-precipitation method and sintered at 1250 °C. The samples were characterized...

Two types of the low temperature WGS catalysts were compared: oxide Cu-Zn-Al catalyst prepared through coprecipitation procedure and ceramometal CuAlO/CuA catalyst prepared from powdered CuAl alloy. The catalysts were characterized by XRD, SEM with EDX, adsorption-desorption isotherms. Activity was measured at a pressure of 1 bar in the mixture of...

Electrical conduction and oxygen diffusion mobility in the bixbyite (Ia3) and rhombohedral (R3) polymorphs of the Ln 6 MoO 12-Δ (Ln = Er, Tm, Yb; Δ = δ, δ1, δ2; δ1 > δ2) heavy lanthanide molybdates, belonging to new, previously unexplored classes of potential mixed (ionic-electronic) conductors, have been studied in the range of 200-900 °C. The oxy...

In this review problems related to design and performance of stable and efficient catalysts of biogas/biofuels transformation into syngas and hydrogen based on nanocrystalline oxides with fluorite, perovskite and spinel oxides and their nanocomposites promoted by nanoparticles of Pt group metals and Ni-based alloys are considered. Tailor-made desig...