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[Display omitted] A new method for the synthesis of nanosized ZSM-5 zeolite with the MFI structure in the proton form is reported. The material was synthesized by the hydrothermal-microwave method and characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, low-temperature nitrogen physisorption, thermal desorption of ammonia and solid- state 27Al NMR. The synthesized material is formed by zeolite particles of 30–80 nm in size, which ensures its high specific surface area, pore volume and interparticle porosity. [ABSTRACT FROM AUTHOR]

Solid solutions Nd2−xSrxNiO4±δ (x = 0, 0.5, 1, 1.2, 1.4) with a K2NiF4 structure can be obtained from freeze-dried precursors. The end members of this series can be obtained at T ≥ 1000 °C only, while complex oxides with x = 1; 1.5 are formed at T ≥ 700 °C. Thermal analysis revealed the two stages of Nd2−xSrxNiO4±δ thermal reduction in a 10%H2/Ar gas mixture that was completed at 900 °C. For x < 0.2, the reduction products demonstrated an exsolution-like morphology with Ni nanoparticles allocated at the surface of oxide grains. As-obtained nanocomposites with x = 0 and x > 1 revealed the outstanding catalytic activity and selectivity in the dry reforming of the methane (DRM) reaction at 800 °C with CH4 conversion close to the thermodynamic values. The appearance of two different maxima of the catalytic properties of Ni/(Nd2O3,SrCO3) nanocomposites could be affiliated with the domination of the positive contributions of Nd2O3 and SrCO3, respectively. [ABSTRACT FROM AUTHOR]

The dry reforming of methane to syngas (DRM) is of increasing significance concerning, first, the production of raw materials for commercial organic/petrochemical syntheses and for hydrogen energetic, and, second, the utilization of two most harmful greenhouse gases. Herein, new SmCoO3-based DRM catalysts derived from heterometallic precursors and operated without preliminary reduction are reported. For the first time, the effect of supercritical fluids-assisted modification of the SmCoO3-derived catalysts combined with the re-oxidation of spent catalysts to SmCoO3 onto its long-term performance was studied. In particular, the modification of heterometallic precursors by supercritical antisolvent precipitation (SAS) considerably decreases coke formation upon the exploitation of the derived SmCoO3 sample. Moreover, the re-oxidation of the corresponding spent catalysts followed by pre-heating under N2 affords catalysts that stably provide syngas yields of 88–95% for at least 41 h at 900 °C. The achieved yields are among the highest ones currently reported for DRM catalysts derived from both LnMO3 perovskites and related oxides. The origins of such good performance are discussed. Given the simplicity and availability of all the applied methods and chemicals, this result opens prospects for exploiting SAS in the design of efficient DRM catalysts. [ABSTRACT FROM AUTHOR]

In order to clarify the role of R2O3 in the metal-oxide catalysts derived from complex oxide precursors, a series of R1.5Ca0.5NiO4 (R = Nd, Sm, Eu) complex oxides was obtained. A significant systematic increase in the orthorhombic distortion of the R1.5Ca0.5NiO4 structure (K2NiF4 type, Cmce) from Nd to Eu correlates with a corresponding decrease in their ionic radii. A reduction of R1.5Ca0.5NiO4 in the Ar/H2 gas mixture at 800 °C causes a formation of dense agglomerates of CaO and R2O3 coated with spherical 25–30 nm particles of Ni metal. The size of metal particles and oxide agglomerates is similar in all Ni/(R2O3,CaO) composites in the study. Their morphology is rather similar to the products of redox exsolution obtained by the partial reduction of complex oxides. All obtained composites demonstrated a significant catalytic activity in the dry reforming (DRM) and partial oxidation (POM) of methane at 700–800 °C. A systematic decrease in the DRM catalytic activity of composites from Nd to Eu could be attributed to the basicity reduction of R2O3 components of the composite catalysts. The maximum CH4 conversion in POM reaction was observed for Ni/(Sm2O3,CaO), while the maximum selectivity was demonstrated by Nd2O3-based composite. The possible reasons for the observed difference are discussed. [ABSTRACT FROM AUTHOR]

[Display omitted] A series of catalysts based on mesoporous ceria solid solutions containing NiCo active component was synthesized via co- precipitation, impregnation, hydrothermal and core–shell (sol–gel) methods and applied to partial oxidation and dry reforming of methane. In the co-precipitated and impregnated catalysts, a better NiCo dispersion and a stronger interaction between NiCo species and the ceria- based support in comparison with other catalysts were observed, which affected activity and selectivity. Thus, simpler methods of applying the active component were more advantageous owing to the manifestation of strong metal–support interactions. [ABSTRACT FROM AUTHOR]

Cage iron(II) complexes with one, two or six terminal (poly)aromatic group(s), designed for effective physical adsorption on the carbonaceous substrates, were prepared by nucleophilic substitution of their mono-, di- and hexachloroclathrochelate precursors with 3-arene-1(9)-yl-propane-1 thiolate anions. Their cyclic voltammograms contain the single Fe 2+/+ reduction wave in the cathodic potential range and two oxidation waves in the anodic potential range, assigned to a metal-centered Fe 2+/3+ process and to oxidation of their arylalkylsulfide groups, respectively. Iron(II) hexaphenanthrenylsulfide clathrochelate with six terminal polyaromatic groups was either immobilized or impregnated on the cathode of gas diffusion electrode and its electrochemical activity with regard to hydrogen evolution reaction (HER) was tested in a proton exchange membrane water electrolysis cell for hydrogen production. It was shown that effective immobilization of this (pre)catalyst on the surface of appropriate carbonaceous electrode materials can be successfully used for improving an efficiency of clathrochelate-based hydrogen-producing systems. [ABSTRACT FROM AUTHOR]