LaFeNiO perovskites in the catalytic reaction of high-temperature decomposition of nitrous oxide.

The catalytic performance of LaFeNiO perovskites prepared by the Pechini method was studied in the high-temperature decomposition reaction of nitrous oxide at temperatures of 750-900 °C. The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), adsorption () and hydrogen thermo-programmed reduction (H-TPR) methods. The prepared single-phase solids with specific surface areas of 4.

Cobalt-Imidazole Complexes: Effect of Anion Nature on Thermochemical Properties.

A solvent-free method was proposed for the synthesis of hexaimidazolecobalt(II) nitrate and perchlorate complexes-[Co(CHN)](NO) and [Co(CHN)](ClO)-by adding cobalt salts to melted imidazole. The composition, charge state of the metal, and the structure of the resulting complexes were confirmed by elemental analysis, XPS, IR spectroscopy, and XRD. The study of the thermochemical properties of the synthesized complexes showed that [Co(CHN)](NO) and [Co(CHN)](ClO) are thermally stable up to 150 and 170 °C, respectively.

Implications for the Hydrogenation of Propyne and Propene with Parahydrogen due to the in situ Transformation of RhC to Rh/C.

NMR spectroscopy studies using parahydrogen-induced polarization have previously established the existence of the pairwise hydrogen addition route in the hydrogenation of unsaturated hydrocarbons over heterogeneous catalysts, including those based on rhodium (Rh). This pathway requires the incorporation of both hydrogen atoms from one hydrogen molecule to the same product molecule. However, the underlying mechanism for such pairwise hydrogen addition must be better understood.

Thermally Induced Surface Structure and Morphology Evolution in Bimetallic Pt-Au/HOPG Nanoparticles as Probed Using XPS and STM.

Bimetallic nanoparticles expand the possibilities of catalyst design, providing an extra degree of freedom for tailoring the catalyst structure in comparison to purely monometallic systems. The distribution mode of two metal species defines the structure of surface catalytic sites, and current research efforts are focused on the development of methods for their controlled tuning. In light of this, a comprehensive investigation of the factors which influence the changes in the morphology of bimetallic nanoparticles, including the elemental redistribution, are mandatory for each particular bimetallic system.

Reductive Transformation of O-, N-, S-Containing Aromatic Compounds under Hydrogen Transfer Conditions: Effect of the Process on the Ni-Based Catalyst.

The influence of the reaction medium on the surface structure and properties of a Ni-based catalyst used for the reductive transformations of O-, N-, and S-containing aromatic substrates under hydrogen transfer conditions has been studied. The catalysts were characterized by XRD, XPS, and IR spectroscopy and TEM methods before and after the reductive reaction. It has been shown that the conversion of 1-benzothiophene causes irreversible poisoning of the catalyst surface with the formation of the NiS phase, whereas the conversion of naphthalene, 1-benzofuran, and indole does not cause any phase change of the catalyst at 250 °C.

Combining Atomic Layer Deposition with Surface Organometallic Chemistry to Enhance Atomic-Scale Interactions and Improve the Activity and Selectivity of Cu-Zn/SiO Catalysts for the Hydrogenation of CO to Methanol.

The direct synthesis of methanol via the hydrogenation of CO, if performed efficiently and selectively, is potentially a powerful technology for CO mitigation. Here, we develop an active and selective Cu-Zn/SiO catalyst for the hydrogenation of CO by introducing copper and zinc onto dehydroxylated silica via surface organometallic chemistry and atomic layer deposition, respectively. At 230 °C and 25 bar, the optimized catalyst shows an intrinsic methanol formation rate of 4.

CO Methanation: Solvent-Free Synthesis of Nickel-Containing Catalysts from Complexes with Ethylenediamine.

CO methanation was studied in the presence of nickel catalysts obtained by the solid-state combustion method. Complexes with a varying number of ethylenediamine molecules in the coordination sphere of nickel were chosen as the precursors of the active component of the catalysts. Their synthesis was carried out without the use of solvents, which made it possible to avoid the stages of their separation from the solution and the utilization of waste liquids.

Synthesis of Boron-Doped Carbon Nanomaterial.

A new method for the synthesis of boron-doped carbon nanomaterial (B-carbon nanomaterial) has been developed. First, graphene was synthesized using the template method. Magnesium oxide was used as the template that was dissolved with hydrochloric acid after the graphene deposition on its surface.

Catalytic Activity of LaFeNiO/CeO Composites in CO and CH Oxidation Depending on Their Preparation Conditions.

LaFeNiO/CeO (1:1) two-phase composite materials were prepared by mechanochemical (MC) and Pechini routes. The catalytic properties of the composites in methane and CO oxidation reactions strongly depend on their preparation conditions. In low-temperature (<600 °C) catalytic CO oxidation the composites demonstrate a higher activity compared with LaFeNiO perovskite.

Investigation of Amorphous Carbon in Nanostructured Carbon Materials (A Comparative Study by TEM, XPS, Raman Spectroscopy and XRD).

Amorphous carbon (AC) is present in the bulk and on the surface of nanostructured carbon materials (NCMs) and exerts a significant effect on the physical, chemical and mechanical properties of NCMs. Thus, the determination of AC in NCMs is extremely important for controlling the properties of a wide range of materials. In this work, a comparative study of the effect of heat treatment on the structure and content of amorphous carbon in deposited AC film, nanodiamonds, carbon black and multiwalled carbon nanotube samples was carried out by TEM, XPS, XRD and Raman spectroscopy.

Kinetics of Oxygen Exchange and NO Decomposition Reaction over MeO/CeO (Me = Fe, Co, Ni) Catalysts.

MeO/CeO (Me = Fe, Co, Ni) samples were tested in an O temperature-programmed isotope exchange and NO decomposition (deNO). A decrease in the rate of deNO in the presence of oxygen evidences the competitive adsorption of NO and O on the same sites. A study of isotope oxygen exchange revealed dissociative oxygen adsorption with the subsequent formation of surface oxygen species.

Atomic-scale changes of silica-supported catalysts with nanocrystalline or amorphous gallia phases: implications of hydrogen pretreatment on their selectivity for propane dehydrogenation.

This work explores how H pretreatment at 550 °C induces structural transformation of two gallia-based propane dehydrogenation (PDH) catalysts, nanocrystalline γ/β-GaO and amorphous GaO (GaO ) supported on silica (γ-GaO/SiO and Ga/SiO, respectively) and how it affects their activity, propene selectivity and stability with time on stream (TOS). Ga/SiO-H shows poor activity and propene selectivity, no coking and no deactivation with TOS, similar to Ga/SiO. In contrast, the high initial activity and propene selectivity of γ-GaO/SiO-H decline with TOS but to a lesser extent than in calcined γ-GaO/SiO.

Magnetically Recovered Co and Co@Pt Catalysts Prepared by Galvanic Replacement on Aluminum Powder for Hydrolysis of Sodium Borohydride.

Magnetically recovered Co and Co@Pt catalysts for H generation during NaBH hydrolysis were successfully synthesized by optimizing the conditions of galvanic replacement method. Commercial aluminum particles with an average size of 80 µm were used as a template for the synthesis of hollow shells of metallic cobalt. Prepared Co was also subjected to galvanic replacement reaction to deposit a Pt layer.

Enhanced Photocatalytic Activity and Stability of BiWO - TiO-N Nanocomposites in the Oxidation of Volatile Pollutants.

The development of active and stable photocatalysts for the degradation of volatile organic compounds under visible light is important for efficient light utilization and environmental protection. Titanium dioxide doped with nitrogen is known to have a high activity but it exhibits a relatively low stability due to a gradual degradation of nitrogen species under highly powerful radiation. In this paper, we show that the combination of N-doped TiO with bismuth tungstate prevents its degradation during the photocatalytic process and results in a very stable composite photocatalyst.

Near-Ambient Pressure XPS and MS Study of CO Oxidation over Model Pd-Au/HOPG Catalysts: The Effect of the Metal Ratio.

In this study, the dependence of the catalytic activity of highly oriented pyrolytic graphite (HOPG)-supported bimetallic Pd-Au catalysts towards the CO oxidation based on the Pd/Au atomic ratio was investigated. The activities of two model catalysts differing from each other in the initial Pd/Au atomic ratios appeared as distinctly different in terms of their ignition temperatures. More specifically, the PdAu-2 sample with a lower Pd/Au surface ratio (~0.

SRPES and STM data for the model bimetallic Pd-In/HOPG catalysts: Effects of mild post-synthesis oxidative treatments.

Post-synthesis treatment of bimetallic catalysts in different gas phases resulting in the adsorption-induced segregation is among promising approaches to enhance their activity not compromising selectivity towards a number of low-temperature reactions. Our recently published paper (M.A.

CO Methanation: Nickel-Alumina Catalyst Prepared by Solid-State Combustion.

The development of solvent-free methods for the synthesis of catalysts is one of the main tasks of green chemistry. A nickel-alumina catalyst for CO methanation was synthesized by solid-state combustion method using hexakis-(imidazole) nickel (II) nitrate complex. Using X-ray Powder Diffraction (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Hydrogen temperature-programmed reduction (H-TPR), it was shown that the synthesized catalyst is characterized by the localization of easily reduced nickel oxide on alumina surface.

Synthesis, Characterization and Visible-Light Photocatalytic Activity of Solid and TiO-Supported Uranium Oxycompounds.

In this study, various solid uranium oxycompounds and TiO-supported materials based on nanocrystalline anatase TiO are synthesized using uranyl nitrate hexahydrate as a precursor. All uranium-contained samples are characterized using N adsorption, XRD, UV-vis, Raman, TEM, XPS and tested in the oxidation of a volatile organic compound under visible light of the blue region to find correlations between their physicochemical characteristics and photocatalytic activity. Both uranium oxycompounds and TiO-supported materials are photocatalytically active and are able to completely oxidize gaseous organic compounds under visible light.

Redox reactions between acetonitrile and nitrogen dioxide in the interlayer space of fluorinated graphite matrices.

The interlayer space of 2D materials can be a slit reactor where transformations not typical for the gas phase occur. We report redox reactions involving acetonitrile and nitrogen oxide guests in galleries of fluorinated graphite. Fluorinated graphite intercalation compounds with acetonitrile are treated with dinitrogen tetraoxide and the synthesis products are studied by a set of experimental methods.

Influence of the active TaN/ZrO /Ni memristor layer oxygen content on forming and resistive switching behavior.

The influence of oxygen content in active zirconium oxide layers on the electrophysical properties of TaN/ZrO /Ni memristors is investigated. The [O]/[Zr] atomic ratio (x) in the oxide layers was varied in the range from 1.56 to 2.

Electronic structure and charge transport mechanism in a forming-free SiO -based memristor.

THe memristor is a key memory element for neuromorphic electronics and new generation flash memories. One of the most promising materials for memristor technology is silicon oxide SiO , which is compatible with silicon-based technology. In this paper, the electronic structure and charge transport mechanism in a forming-free SiO -based memristor fabricated with the plasma enhanced chemical vapor deposition method is investigated.

XPS data for the uranyl-modified oxides under visible light.

The silica, alumina, ceria, and titania supports were modified with uranyl ions (5 wt%) and investigated using X-ray photoelectron spectroscopy. The data show the U4f photoelectron spectra and charge state of uranium for uranyl ions deposited on different supports. The additional XPS experiments with simultaneous irradiation of the sample using a 450 nm light-emitting diode were performed, and the XPS spectra, revealing a partial reduction of uranium under visible irradiation, are presented.

Nanoscale potential fluctuations in nonstoichiometrics tantalum oxide.

The atomic and electronic structure of nonstoichiometric amorphous tantalum oxide (TaO ) films of different composition has been investigated by means of electron microscopy, x-ray photoelectron spectroscopy, Raman and infrared spectroscopy. The dispersion of the absorption coefficient and refraction index has been studied by spectral ellipsometry. The optical spectra were interpreted using the results of a quantum-chemical simulation for crystalline orthorhombic TaO .

In situ formation of the active sites in Pd-Au bimetallic nanocatalysts for CO oxidation: NAP (near ambient pressure) XPS and MS study.

Model bimetallic Pd-Au/HOPG catalysts have been investigated in the CO oxidation reaction using a combination of NAP XPS and MS techniques. The samples have shown catalytic activity at temperatures above 150 °C. The redistribution of Au and Pd on the surface depending on the reaction conditions has been demonstrated using NAP XPS.

Electronic structure and charge transport in nonstoichiometric tantalum oxide.

The atomic and electronic structure of nonstoichiometric oxygen-deficient tantalum oxide TaO grown by ion beam sputtering deposition was studied. The TaO film content was analyzed by x-ray photoelectron spectroscopy and by quantum-chemistry simulation. TaO is composed of TaO, metallic tantalum clusters and tantalum suboxides.