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The formation of hierarchically organized MoS2 films on various substrates by a hydrothermal method was studied. The influence of synthesis conditions and the substrate (a glass or a flexible carbon paper substrate) on the crystal structure of sulfide films was determined using X-ray powder diffraction (XRD). Scanning electron microscopy (SEM) showed that the films on glass substrates comprised structurally different elements, namely a continuous dense layer of spherical nanoparticles on the surface of which hierarchically organized globular agglomerates of two types are arranged. A molybdenum disulfide shell about 1.5 μm thick, consisting of hierarchically organized nanosheets less than 10 nm thick, was formed on the surface of carbon fibers that make up the carbon paper. Elemental mapping was used to evaluate the homogeneity of the MoS2 film formed on the carbon paper. Atomic force microscopy (AFM) showed that an individual carbon fiber modified with a sulfide film had a mean square roughness of about 13 nm (over an area of about 100 μm2). According to Kelvin-probe force microscopy (KPFM) data, the electron work function of the material was 4.53 eV. The electrochemical characteristics of the manufactured flexible electrode based on a hierarchically organized molybdenum disulfide film were investigated. The specific capacitance and the stability of functional and microstructural properties of the manufactured supercapacitor electrode in 2000 charge–discharge cycles were evaluated. Thus, the proposed strategy is promising for the fabrication of efficient hierarchically organized MoS2 electrodes for flexible supercapacitors. [ABSTRACT FROM AUTHOR]

Triethanolamine-assisted hydrothermal synthesis of hierarchical nickel oxide particles was studied. The thermal behavior, crystal structure, and spectral characteristics of α-Ni(OH)2 obtained by the hydrothermal treatment of the reaction system and subsequent drying of the solid phase were investigated. It was shown that the thermal treatment at 350°C for 1 h results in the decomposition of the obtained intermediate product to form the desired nanocrystalline oxide (average coherent scattering region size of about 6 nm). Kelvin probe force microscopy was used to construct the maps of the potential distribution over the surface of particles of the studied material and to determine the work function of its surface. [ABSTRACT FROM AUTHOR]

Abstract—The synthesis of NiMoO4 hierarchical nanostructures using the hydrothermal method has been studied. The decomposition of NiMoO4·xH2O crystalline hydrate formed during the synthesis has been studied using synchronous thermal analysis upon heating in a stream of air and argon. According to X-ray diffraction as well as scanning and transmission electron microscopies, the proposed conditions allow one to synthesize single-phase nanosized (average CSR size of about 25 ± 2 nm) nickel(II) molybdate, which has a spinel-type monoclinic structure (space group C2/m) without impurity inclusions. [ABSTRACT FROM AUTHOR]

The formation of CoMoO4 anisotropic nanostructures has been studied with a combination of programmed co-precipitation of metal hydroxides and the hydrothermal method. The thermal behavior, phase composition, and microstructure features of the obtained nanopowder have been investigated. Using a set of physicochemical methods of analysis, it has been shown that the proposed synthesis conditions make it possible to form a single-phase nanodispersed (average CSR size of about 30 ± 3 nm) oxide with a monoclinic spinel-type structure (space group C2/m) that does not contain impurity inclusions. [ABSTRACT FROM AUTHOR]

The formation of a hierarchical cobalt(II, III) oxide coating on the surface of a polycrystalline Al2O3 substrate under hydrothermal conditions was studied. Features of the microstructure of the obtained coatings were investigated by scanning electron microscopy; these coatings were shown to consist of Co3O4 nanosheets arranged perpendicular to the surface of the substrate with a blossoming flower-like structure. The production of the coating of the desired composition without crystalline impurities was confirmed by IR spectroscopy, X-ray powder diffraction analysis, and energy dispersive spectroscopy elemental analysis. The roughness of the formed Co3O4 film was estimated by atomic force microscopy. The local electrophysical characteristics of the produced oxide coating (work function of film surface, capacitance, and surface distribution maps of surface potential and capacitance contrast) were studied by scanning capacitance microscopy and Kelvin probe force microscopy. A local analysis of the current–voltage characteristics of the studied samples was made. [ABSTRACT FROM AUTHOR]

A hierarchical nickel oxide film was grown on the surface of a polycrystalline Al2O3 substrate by hydrothermal synthesis. The microstructure of the obtained coating was studied by scanning electron microscopy and atomic force microscopy, which showed that this coating comprises porous nanosheets (about 7 nm thick) arranged at various angles to each other and to the surface of the substrate. The lateral sizes of these nanosheets were in the range 3–5 μm. The local electrophysical characteristics of the obtained oxide coating were investigated by scanning capacitance microscopy and Kelvin probe force microscopy; using the obtained results, the maps of the distributions of the surface potential and capacitance contrast over the surface of the NiO film were constructed, and the work function of the surface of this film was calculated. [ABSTRACT FROM AUTHOR]

One-dimensional h-MoO3 structures were produced by a hydrothermal method. The effect of the hydrothermal treatment conditions on the microstructure and particle size of the formed oxide powder was shown. The formation of the hexagonal structure of the powder and the absence of crystalline impurities were confirmed by X-ray powder diffraction analysis. The electrophysical characteristics of the surface of the obtained powder were evaluated by scanning capacitance force microscopy and Kelvin probe force microscopy. The kinetics of the visible-light photocatalytic degradation of rhodamine B in the presence of h-MoO3 was studied. [ABSTRACT FROM AUTHOR]

The process for preparing SnO2 nanocrystalline microspheres via synthesis in microemulsions combined with hydrothermal treatment of the resulting suspensions was studied. Tin acetylacetonate, whose n‑butanol solution is more convenient for use compared to classical reagents, was shown to have a promise for use as a precursor. Simultaneous thermal analysis and IR spectroscopy showed the transformation of a hydrated powder under heating to yield anhydrous tin dioxide. SEM analysis of the prepared SnO2 powder microstructure elucidated a two-level organization of oxide particles—nanoparticles with a size of about 25 nm were hierarchically organized in the form of medium-sized microspheres of about 1.5 µm, were formed during microemulsion synthesis upon tin acetylacetonate hydrolysis. [ABSTRACT FROM AUTHOR]

Nickel oxide nanosheets were manufactured using sol–gel technology and hydrothermal treatment. The effect of hydrothermal treatment on the hierarchical organization character of the thus-manufactured oxide powder was shown. The microstructural parameters of the powder were studied by transmission (TEM) and scanning (SEM) electron microscopy; The homogeneity of the powder and the absence of impurities of another chemical composition were verified by energy dispersive elemental microanalysis (EDX). [ABSTRACT FROM AUTHOR]

Hierarchical nanostructures based on rodlike particles of the composition CeO2–10% Y2O3 were obtained by programmed direct coprecipitation of metal hydroxides in the presence of polyvinyl alcohol. The effect of the concentration of the structure-forming polymer template on the morphology of the formed oxides was shown. The dependence of the particle size and microstructure of the products on the polyvinyl alcohol concentration in the reaction system was identified. Simultaneous thermal and X-ray powder diffraction analyses determined that the polymer during precipitation is incorporated into the structure of the produced nanopowder, preventing coarsening of particles during heat treatment. [ABSTRACT FROM AUTHOR]