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In spite of advanced research on functional colloidal inorganic nanoparticles and their reactivity, room temperature reactive interactions between two different colloids have remained challenging so far. Laser ablation of titanium monoxide and silicon monoxide in ethanol and water allows the generation of TiO-derived and SiO-derived colloidal nanoparticles which were characterized for their stability, size distribution and zeta potentials with dynamic light scattering and after evaporation of solvent examined for their morphology, chemical and phase composition by scanning electron microscopy, Raman spectroscopy, high resolution transmission electron microscopy and electron diffraction and small angle X-ray scattering. Aqueous and ethanolic TiO-derived colloids consist of anatase and monoclinic TiO, while ethanolic SiO-derived colloids are composed of crystalline and amorphous Si, nanocrystalline Si and SiO2 and aqueous SiO-derived colloids contain, in addition to these phases, a high pressure form of cristobalite. Simple room temperature mixing of ethanolic TiO- and SiO-derived colloids allows the formation of TiSi2, which is a case of so far unreported room temperature reactive interactions between two colloidal species. All colloids absorb solar light and act as photocatalysts for methylene blue degradation. These findings present a challenge for further search for feasible room-temperature reactions between distinct colloidal particles and open the potential for green synthesis of other desirable and hardly achievable phases. [ABSTRACT FROM AUTHOR]

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A pulsed Nd : YAG laser ablation of FeS in water and ethanol produces FeS-derived colloidal nanoparticles that absorb onto immersed porous ceramic substrates and create solar-light photocatalytic surfaces. The stability, size distribution and zeta potential of the nanoparticles were assessed by dynamic light scattering. Raman, UV-Vis and XP spectroscopy and electron microscopy reveal that the sol nanoparticles have their outmost layer composed of ferrous and ferric sulphates and those produced in water are made of high-pressure orthorhombic FeS, cubic magnetite Fe3O4 and tetragonal maghemite γ-Fe2O3, while those formed in ethanol contain hexagonal FeS and cubic magnetite Fe3O4. Both colloids absorb solar light and their adsorption to porous ceramic surfaces creates functionalized ceramic surfaces that induce methylene blue degradation by daylight. The laser induced process thus offers an easy and efficient way for the functionalization of porous surfaces by photocatalytic nanoparticles that avoids aggregation in the liquid phase. The formation of an orthorhombic high-pressure FeS phase stable under ambient conditions is the first example of high-pressure structures produced by laser ablation in liquid without the assistance of an electric field. [ABSTRACT FROM AUTHOR]

Highly polymorphic cobalt sulfide represents attractive material because of its unique electronic, optical, magnetic, mechanical and catalytic properties. Pulsed laser irradiation of a solid CoS2 target results in ablation and deposition of thin films on Ta and Cu substrate, which were analyzed using scanning electron microscopy, Raman and FTIR spectroscopy, X‐ray photoelectron spectroscopy, high resolution electron microscopy and electron diffraction. These complementary analyses revealed that the film on Ta consists of the parent cubic CoS2 whereas the film on Cu exhibits a multiphase structure containing the cubic CoS2 and cubic Co2CuS4. The ternary species is known as an active electrode material with relatively high energy density for electrochemical capacitors and proves interdiffusion events at the interface of copper and colliding CoS2 particles. Such facile and one‐step process represents the first example of the Co2CuS4 formation through ablative reactive deposition on unheated substrate and adds to very rare examples of reactive laser deposition of ablated metal sulfides on unheated surfaces. The CoS2‐based films deposited on Ta and the Co2CuS4‐based films deposited on Cu were examined for their catalytic effect in Fenton degradation of methylene blue (MB). Their efficiency to degrade MB is compared and discussed. Laser irradiation of CoS2 allows deposition of nanocrystalline CoS2 on Ta and reactive deposition of Co2CuS4 on Cu substrate. Bimetallic sulfide is formatted via interdiffusion events of hot Co/S particles colliding with Cu atoms which are incorporated into cubic lattice of original CoS2. CoS2 and Co2CuS4 films exhibit catalytic effect in terms of Fenton‐like degradation. [ABSTRACT FROM AUTHOR]

Abstract: All input experimental errors for membrane flux determination were analyzed. The overall error in pressure did not largely influence the determination of membrane flux. The main contribution to errors was ascribed to flow meters and membrane thickness. The choice of an optimal operational range for input parameters led to elimination of at least 2/3 of the theoretical relative error for subsequent evaluation of the permeability of individual species. This is especially valuable for low‐permeable membranes, whereas a very low relative theoretical error can be obtained in the case of highly permeable materials. [ABSTRACT FROM AUTHOR]

Four activated carbons based on red mombin seeds, cocoa pod husk, the external part of mango pits, and coffee husk were prepared by chemical activation using zinc chloride. Adsorption isotherms of hydrogen measured by a volumetric method under supercritical conditions corresponding to the three temperature levels and the pressure up to ten bars were determined. The dependence of the adsorbed amount of hydrogen on equilibrium pressure was linear for all adsorption isotherms measured at ambient temperatures. The corresponding excess adsorption experimental data were fitted by Henry's adsorption isotherm with an excellent accordance. The Dubinin-Radushkevich adsorption isotherm was demonstrated to match the excess adsorption data at cryogenic temperatures with high accuracy. [ABSTRACT FROM AUTHOR]

Direct decomposition of nitric oxide (NO) proceeds over Co–Mn–Al mixed oxides promoted by potassium. In this study, answers to the following questions have been searched: Do the properties of the K-promoted Co–Mn–Al catalysts prepared by different methods differ from each other? The K-precipitated Co–Mn–Al oxide catalysts were prepared by the precipitation of metal nitrates with a solution of K2CO3/KOH, followed by the washing of the precipitate to different degrees of residual K amounts, and by cthe alcination of the precursors at 500 °C. The properties of the prepared catalysts were compared with those of the best catalyst prepared by the K-impregnation of a wet cake of Co–Mn–Al oxide precursors. The solids were characterized by chemical analysis, DTG, XRD, N2 physisorption, FTIR, temperature programmed reduction (H2-TPR), temperature programmed CO2 desorption (CO2-TPD), X-ray photoelectron spectrometry (XPS), and the species-resolved thermal alkali desorption method (SR-TAD). The washing of the K-precipitated cake resulted in decreasing the K amount in the solid, which affected the basicity, reducibility, and non-linearly catalytic activity in NO decomposition. The highest activity was found at ca 8 wt.% of K, while that of the best K-impregnated wet cake catalyst was at about 2 wt.% of K. The optimization of the cake washing conditions led to a higher catalytic activity. [ABSTRACT FROM AUTHOR]

A flow supercritical fluid crystallization with and without modifier/s was applied to prepare nanocrystalline TiO 2 monoliths without subsequent thermal treatment. The effect of processing conditions (temperature, pressure, water concentration, type of modifier: water or ethanol and water) on the crystallization, texture and purity of TiO 2 was investigated. Gel blocks for processing were prepared by nitric acid-catalysed sol-gel synthesis. It was revealed that one- or multi-step processing by scCO 2 with modifier leads to direct crystallization of TiO 2 monoliths of anatase-brookite crystal structure even at mild processing temperature of 40 °C and 30 MPa. 15 wt.% of water was determined to be the optimal concentration of water in scCO 2 as a crystallization agent. Processing temperature affected the anatase and brookite crystallite-size. Processing pressure affected the crystallization and purity of monolithic TiO 2 . The pre-drying as well as the post-drying by scCO 2 at 40 °C visibly improved the solidity of TiO 2 monolith and stabilized brookite crystallites. [ABSTRACT FROM AUTHOR]

Nanostructured TiO 2 anatase thin films were directly prepared using supercritical carbon dioxide (scCO 2 ) modified by organic solvent and water in two step processing. Organic solvent used as scCO 2 modifier at 30 MPa and 40 °C in the first step of processing was in the second step changed to water with simultaneous temperature increase to 150 °C which caused anatase thin films crystallization. The effect of the type of modifier (water, methanol, ethanol and acetone), concentration of modifier (5–40 wt.%) in scCO 2 and the amount of scCO 2 (50–200 g) passed through the high pressure column as well as the type of substrate (soda-lime glass and monocrystalline Si) on microstructure and purity of TiO 2 thin films were examined in both steps of processing. The prepared thin films were characterized with respect to their (micro)structural properties by Raman spectroscopy as well as X-ray diffraction, to their wettability by contact angle measurements and to their morphology by high resolution transmission electron microscopy. [ABSTRACT FROM AUTHOR]

In spite of advanced research on functional colloidal inorganic nanoparticles and their reactivity, room temperature reactive interactions between two different colloids have remained challenging so far. Laser ablation of titanium monoxide and silicon monoxide in ethanol and water allows the generation of TiO-derived and SiO-derived colloidal nanoparticles which were characterized for their stability, size distribution and zeta potentials with dynamic light scattering and after evaporation of solvent examined for their morphology, chemical and phase composition by scanning electron microscopy, Raman spectroscopy, high resolution transmission electron microscopy and electron diffraction and small angle X-ray scattering. Aqueous and ethanolic TiO-derived colloids consist of anatase and monoclinic TiO, while ethanolic SiO-derived colloids are composed of crystalline and amorphous Si, nanocrystalline Si and SiO 2 and aqueous SiO-derived colloids contain, in addition to these phases, a high pressure form of cristobalite. Simple room temperature mixing of ethanolic TiO- and SiO-derived colloids allows the formation of TiSi 2 , which is a case of so far unreported room temperature reactive interactions between two colloidal species. All colloids absorb solar light and act as photocatalysts for methylene blue degradation. These findings present a challenge for further search for feasible room-temperature reactions between distinct colloidal particles and open the potential for green synthesis of other desirable and hardly achievable phases.

Chemical vapor deposition was applied to synthetize nanostructured deposits containing several sorts of nanoobjects (i.e., nanoballs, irregular particles, and nanowires). Analytical techniques, that is, high-resolution transmission electron microscopy, scanning electron microscopy, electron dispersive X-ray analysis, selected area electron diffraction, and X-ray photoelectron spectroscopy, showed that unlike nanoballs and particles composed of crystalline germanium, the layer was made of chromium germanide CrGe x . The nanowires possessed a complex structure, namely a thin crystalline germanium core and amorphous CrGe x coating. The composition of the nanowire coating was [Cr]/[Ge] = 1:(6-7). The resistance of the nanowire-deposit system was estimated to be 2.7 kΩ·cm using an unique vacuum contacting system., (Copyright © 2021, Dřínek et al.)

A pulsed Nd : YAG laser ablation of FeS in water and ethanol produces FeS-derived colloidal nanoparticles that absorb onto immersed porous ceramic substrates and create solar-light photocatalytic surfaces. The stability, size distribution and zeta potential of the nanoparticles were assessed by dynamic light scattering. Raman, UV-Vis and XP spectroscopy and electron microscopy reveal that the sol nanoparticles have their outmost layer composed of ferrous and ferric sulphates and those produced in water are made of high-pressure orthorhombic FeS, cubic magnetite Fe3O4 and tetragonal maghemite γ-Fe2O3, while those formed in ethanol contain hexagonal FeS and cubic magnetite Fe3O4. Both colloids absorb solar light and their adsorption to porous ceramic surfaces creates functionalized ceramic surfaces that induce methylene blue degradation by daylight. The laser induced process thus offers an easy and efficient way for the functionalization of porous surfaces by photocatalytic nanoparticles that avoids aggregation in the liquid phase. The formation of an orthorhombic high-pressure FeS phase stable under ambient conditions is the first example of high-pressure structures produced by laser ablation in liquid without the assistance of an electric field.