The catalytic oxidation of CO is of great technological importance for the treatment of vehicle and industrial exhaust gases. PtCe-catalysts of low-temperature CO oxidation were prepared by the impregnation of ZSM-5 zeolite (Z) with aqueous solutions of H2PtCl6 and Ce(NO3)3, varying the order of metal deposition and thermal treatment conditions. The relationships between structure transformations and catalyst performance were established based on the SEM, TEM, EDX, DRIFT, and X-ray photoelectron spectroscopies data. For the Ce/Pt/Z sample, in which cerium was deposited after platinum, the 100% CO conversion temperature was only 120 °C. The inverse deposition sequence of metals (Pt/Ce/Z catalyst) resulted in CO oxidation at a higher temperature that can be decreased to 110 °C by redox treatment. The prepared catalysts were also active in the CO oxidation in excess hydrogen (PROX) but were not selective enough. However, the activity of PtCe-modified ZSM-5 enhanced greatly in the repeated cycles of CO oxidation (TOX) after testing in PROX. It is suggested that enhancing the interaction between Pt and Ce is a key factor in tuning the catalyst performance. The 0.2 wt.% Pt catalysts showed the best performance and provided complete CO conversion at 95 °C, which is a pronounced result for low-loaded Pt catalysts.

Porous carbons based on activated reduced graphene oxide (rGO) have been demonstrated as excellent sorbents for U(vi), with their sorption capacity correlating with the degree of their oxidation. Herein, we demonstrate an extraordinarily high U(vi) sorption of similar to 7050 mu mol g-1 for super-oxidized porous carbon (SOPC) with a specific surface area (SSA) of similar to 970 m2 g-1 and an extremely high degree of oxidation (C/O = 2.1), similar to graphene oxide. The SOPC materials were prepared using an oxidation treatment applied to activated carbon produced from spruce cones. The extremely high SSA of the precursor activated carbon (similar to 3400 m2 g-1) as well as its microporous structure and mild oxidation treatment allowed for the preservation of a significant part of the surface area, providing materials with rather narrow pore size distribution (similar to 7.5 & Aring;). The SOPC prepared from spruce cone biochar is similar to defective graphene oxide but with a significantly higher surface area, resulting in superior U(vi) sorption. Analysis of EXAFS and XPS data shows that U(vi) likely binds to carboxylic groups on the opposite sides of the micropores. The small size of the micropores and irregular pore wall structure are the main factors affecting pore sorption. The spruce-cone biochar has a strong advantage compared with earlier used rGO as a precursor for the preparation of SOPC.

The increasing global demand for energy stimulates the development of advanced energy storage and conversion technologies. Modification of electrolyte with redox-active additives is a promising way to enhance the electrochemical performance of energy storage devices. In this work new electroactive ferrocene-based ionic liquids (Fc-ILs) (N-methyl-N-(ferrocenylmethyl)piperidinium bis(trifluoromethanesulfonyl)imide [PipFcMe][NTf2], Nmethyl-N-(ferrocenylmethyl)pyrrolidinium bis(trifluoromethanesulfonyl)imide [PyrFcMe][NTf2], N-ethyl-N(ferrocenylmethyl)pyrrolidinium bis(trifluoromethanesulfonyl)imide [PyrFcEt][NTf2]) were synthesized. The structure of the Fc-ILs was confirmed by NMR and XRD. [PipFcMe][NTf2] and [PyrFcMe][NTf2] demonstrated nearly similar crystal structures consisting of cation and anion columns, while alternating cation and anion layers are stacked in the [PyrFcEt][NTf2] crystal. The effects of the Fc-IL mole fraction and temperature on the transport properties of the acetonitrile solutions of the Fc-ILs have been established. The highest electrical conductivities of the [PipFcMe][NTf2], [PyrFcEt][NTf2] and [PyrFcMe][NTf2] solutions calculated using the Casteel-Amis equation were, respectively, 38.06 +/- 0.63, 40.34 +/- 0.93 and 41.09 +/- 0.58 mS/cm at 348.15 K. The activation energies of conductivity were calculated using the Arrhenius and Vogel-Fulcher-Tamman approaches. The Fc-ILs demonstrated a high electrochemical stability range up to 4.67 V. The introduction of electron-withdrawing substituents into the cyclopentadienyl ring of Fc-ILs shifted the half-wave potential to the positive direction. The diffusion coefficients were calculated using the Randles-Sevcik equation for a quasi-reversible process.

Structural defects and heteroatoms play a key role in electrochemical reactions. However, there is still no common understanding of what has a greater impact on electrochemical processes: defects or the type of heteroatoms. To clarify these factors, defective carbon nanowalls treated by reactive etching in different atmospheres, such as argon and mixtures of argon with nitrogen, chlorine, hydrogen bromide, and sulfur fluoride were used. Properties of the obtained samples were analyzed with Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and cyclic voltammetry. The results of the study showed that the plasma modification of carbon nanowalls leads to the removal of the amorphous layer and subsequent implantation of heteroatoms, which ultimately leads to an increase in their areal capacitance 1.5-fold in a 1:2 argon - nitrogen mixture and 2-fold in a 1:4 argon-nitrogen mixture.

Modern plasma technologies applied for nm-size devices require localizing ions' impact within up to atomic layer to avoid uncontrollable damage of underlying structures. The decrease in energy of ions incident on a surface is one of the ways to achieve this. In this work, SiO2 sputtering by Ar+, Kr+, and Xe+ ions at energies of 20-200 eV was studies in the low-pressure ICP-discharge at a plasma density typical for plasma processing. The rf-bias waveform tailoring due to high discharge asymmetry allowed generating and controlling ion narrow energy spectrum with FWHM 5 +/- 2 eV. Real time in-situ control over ion composition and flux as well as sputtering rate provided accurate determination of the SiO2 sputtering yield, Y(Ei). It is shown that at ion energy above similar to 70 eV, the "classical" kinetic sputtering mechanism prevails. In this case, Y(Ei) rapidly grows with ion energy, while decreasing with the decrease in ion mass. Below similar to 70 eV, the change of Y(Ei) is strongly slow down while the sputtering yield still stays high enough (>10(-3)), demonstrating the plasma impact on the sputtering mechanism. The obtained trends of Y(Ei) under the plasma exposure are discussed in light of possible SiO2 surface modification studied by AFM and angular XPS analysis.

Since catalytically active materials require special synthesis conditions, which cause difficulty in scaling, it is necessary to develop new lightweight scalable approaches for industrial applications. The most obvious way is to use elementary components to fabricate complex structures. In our work, we used a fundamental ampoule synthesis method to produce MSSe (M = Mo, W) powders with a homogeneous random distribution of chalcogen atoms. The synthesized samples exhibit P63/mmc space group indicating the existence of 2 H phase which was proved by comprehensive experimental and theoretical analysis and demonstrates rational characteristics in the hydrogen evolution reaction. The Tafel slopes for synthesized MoSSe and WSSe are 93 and 86 mV/dec, respectively. Moreover, the MSSe samples demonstrate the same catalytic activity in the hydrogen evolution reaction as the samples subjected to ultrasonic treatment in N-Methyl-2-pyrrolidone, with Tafel slopes of 92 and 88 mV/dec for MoSSe and WSSe, respectively.

Heterosubstitution is widely used to control the surface properties of graphene materials. The knowledge of the mechanism of organic solvent vapour sorption on doped graphene materials is necessary for development of air purification technologies, volatile organic compounds sensors, metal-free catalysis and for many other applications. The effect of N, S and Si doping and oxidative functionalization of few-layer graphene nanoflakes on the adsorption of organic solvent vapours was measured. The nanoflakes were also analyzed by TEM, XPS, Raman spectroscopy and low-temperature nitrogen physisorption. Special attention was paid to the dependence of the isosteric heat of adsorption on the surface coverage for various adsorbate-adsorbent pairs, which carry information about the energy inhomogeneity of the surface, the hierarchy of adsorbate-adsorbate, adsorbate-basal plane and adsorbate-functional groups interactions, and the mechanism of adsorption. This dependence for the hexane sorption can be used to detect hydrophilic groups on the surface, and to compare the degree of curvature of graphene layers in different heterosubstituted graphene materials.

Synthesized Ln2O3 (Ln = La, Nd or Gd) nanoparticles with sizes of 1–3 nm, 5–6 nm and 10–15 nm were stabilized by carbon nanoflakes (CNFs). The weight content of Ln2O3 in the Ln2O3/CNF composites was 20–50 wt. %, which makes these composites potentially suitable for practical use as computed tomography and magnetic resonance imaging contrast agents. The structure of CNFs and Ln2O3/CNF composites was investigated by X-ray diffraction data, X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). The EPR spectra of raw CNFs were silent. The oxidation of the CNF surface resulted in the appearance of paramagnetic centers associated with two types of unpaired electrons in the carbon support. After impregnation of the CNFs with the Ln3+ ion solution, the number of unpaired electrons was reduced, presumably due to the formation of C–O–Ln bonds. All Ln3+ ions changed the composites’ EPR spectra by reducing the number of unpaired electrons in the CNF structure.

Currently, the use of redox-active additives is an effective way to enhance the electrochemical performance of supercapacitors. Despite a lot of publications in the literature, the choice of redox-active electrolyte composition is still unclear. This work focuses on the study of the correlation between the K4Fe(CN)6 fraction (0–0.05 M) in 1 M Na2SO4 and electrochemical characteristics of rice-husk-derived activated carbon (AC). The effect of electrolyte composition was clarified by cyclic voltammetry, galvanostatic charge/discharge and impedance spectroscopy. The increase in the K4Fe(CN)6 fraction in the electrolyte significantly improved the specific capacitance of AC from 59 up to 288 F/g at a current density of 1 A/g. Nevertheless, despite the fact that the concentrated 0.05 M K4Fe(CN)6–1 M Na2SO4 electrolyte provided excellent capacitance, it led to a high self-discharge and charge transfer resistance, not beneficial for electrochemical applications.

This study investigates various sorbents for the effective sorption of dissolved organic substances, using tributyl phosphate (TBP) as a model compound. TBP is one of the most commonly used extractants in the nuclear industry. Four different carbon materials with high specific surface areas (2000-3000 m2 g-1) were selected for evaluation. The sorption of TBP from nitric acid solutions was examined over a wide range of concentrations. The samples with the largest specific surface areas showed the highest sorption capacity for organic matter. To enable repeated use, a purification scheme was developed to restore the sorbents' original properties. The samples were subjected to various treatments, analyzed using X-ray photoelectron spectroscopy, and used in subsequent sorption experiments. This study investigates various sorbents for the effective sorption of dissolved organic substances, using tributyl phosphate (TBP) as a model compound.

Релятивистским методом дискретного варьирования выполнен расчет электронного строения NoO2 и спектра РФЭС (рентгеновской фотоэлектронной спектроскопии) валентных электронов в диапазоне энергий связи от 0 до ~40 эВ. Наблюдаются значительные эффекты ковалентности в NoO2, обусловленные существенным перекрыванием не только No 6d АО, но и No 6p и No 5f АО с орбиталями кислорода. Построены гистограмма и схема МО, позволяющие понять особенности природы химической связи и структуру спектра РФЭС валентных электронов в NoO2.

It was found that small additives of E Te-IV species (< 1 at%) notably enhance the visible -light photocatalytic activity of polycrystalline anatase TiO2 . This effect can tentatively be attributed to the neutralization of the neighboring surfacelocated oxygen vacancy, acting as a recombination center for photogenerated holes and electrons, by the dopant stereochemically active lone electron pair E.

Iron oxide-modified 1Pd0.5Fe and 1Pd10Fe catalysts with a target content of 1 wt

The electronic structure of NoO2 and the valence-band X-ray photoelectron spectrum (XPS) in the energy range from 0 eV to 40 eV are calculated by the relativistic discrete variation method. Significant covalency effects are observed in NoO2, which are due to a considerable overlap of not only No 6d AO but also No 6p and No 5f AOs with oxygen orbitals. The MO histogram and scheme are derived, which enable the comprehension of features of the chemical bond nature and the structure of the XPS spectrum of valence electrons in NoO2.

The synthesis of new carbon nanoflake (CNF)-supported composites with a La2O3/CNFs@C core–shell structure is described. The carbon surface is functionalized by oxidation with nitric acid vapor for 1, 3, or 6 h. The evolutions of the structure and composition are investigated by transmission electron microscopy and X-ray photoelectron spectroscopy.

The Fe/MgAl2O4 catalysts modified with In were prepared by joint impregnation of aluminum–magnesium spinel with solutions of metal nitrate salts. Data on the adsorptive and reductive properties of the catalysts obtained by the in situ magnetic method, XPS, thermolysis, and IR spectroscopy of adsorbed CO are compared. It was established that the presence of indium in the catalyst inhibits the reduction of iron oxides to magnetite, as well as the stage of water removal from the catalysts and the decomposition of metal nitrates. It was shown by IR spectroscopy that the main adsorption sites are the structures that include Fe2+ cations.

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 solidstate 27 Al 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.

We report a new facile method for the synthesis of prolate cobalt ferrite nanoparticles without additional stabilizers, which involves a co-precipitation reaction of Fe3+ and Co2+ ions in a static magnetic field. The magnetic field is demonstrated to be a key factor for the 1D growth of cobalt ferrite nanocrystals in the synthesis. Transmission electron microscopy (TEM), X-ray diffraction (XRD), and Raman spectroscopy are applied to characterize the morphology and structure of the obtained nanoparticles. According to TEM, they represent nanorods with a mean length of 25 nm and a diameter of 3.4 nm that have a monocrystalline structure with characteristic plane spacing of 2.9 Å. XRD and Raman spectroscopy confirm the spinel CoFe2O4 structure of the nanorods. After aging, the synthesized nanorods exhibit maximum saturation magnetization and coercivity equal to 30 emu/g and 0.3 kOe, respectively. Thus, the suggested method is a simple and “green” way to prepare CoFe2O4 nanorods with high aspect ratios and pronounced magnetic properties, which are important for various practical applications, including biomedicine, energy storage, and the preparation of anisotropic magnetic nanocomposites.

In this study, we have synthetized a series of citric acid stabilized superparamagnetic iron oxide nanoparticles (CA-SPIONs) with different core sizes in an automated chemical reactor with high repeatability of the nano- particle size and chemical composition. The prepared CA-SPIONs are highly crystalline spherical-shaped particles with the diameters of 3.5 f 0.7, 6 f 1, 9 f 1, and 12 f 2 nm. The valent state of iron oxide was determined by a combination of X-ray photoelectron spectroscopy, UV-Vis spectroscopy, and Mossbauer studies, which confirmed predominantly maghemite formation. Under normal conditions, these nanoparticles exhibit no coercive force and no hysteresis, while saturation magnetization increases from 2 to 61 emu/g along with the increasing core size. Both longitudinal (r1) 1 ) and transverse (r2) 2 ) relaxivities of maghemite hydrosols with different nanoparticle sizes were measured and compared with the same data for the commercial Gd-complex (Gadovist). Magnetic circular dichroism spectroscopy indicated that aggregation occurs in magnetic field, but 9 nm samples slightly aggregate in the fields above 1.0 T, whereas 3.5 nm colloids are stable and do not exhibit aggregation behavior even at 1.5 T. The obtained series were examined in phantom test in clinical 1.5 T MRI scanner, which showed that increasing the particle core size resulted in an enhanced T2 2 contrast, while T1 1 contrast declined. Finally, the smallest CA-SPION colloid nanoparticles with the size of 3.5 nm exhibited significant T1 1 contrast enhancement, comparable with the commercial Gd-complex in water and human plasma as well. The maghemite hydrosol formed by nanoparticles with 3.5 nm size thus has a promising future as a T1 1 MRI contrast agent.

A comparative study of composites based on imidazolium phosphomolybdates of the SILP type of catalysts for peroxide oxidative desulfurization was performed by mass spectrometry and other physicochemical methods, in particular, XPS (X-ray photoelectron spectroscopy). An analysis of the data obtained revealed partial destruction of heteropolyanions during the synthesis of heterogeneous samples. The results of mass spectrometric measurements are well correlated with the XPS data, indicating the possibility of using mass spectrometry (MS) in the surface-activated laser desorption/ionization (SALDI) technique for characterization of these composites. The results of the analysis of the desulfurization rate showed the important role of the products of partial destruction of heteropolyacid anions in the catalysis of the process.