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In this study, we report the influence of vanadium oxide (VO), as a photosensitive component, on the photoactivity of TiO2 nanotubes (TNTs). A series of TNTs of varying tube diameter were synthesized by the anodization of titanium foils at different voltages, while vanadium oxide was deposited on TNTs by wet chemical deposition. An improvement in the optical properties of nanotubes was observed after the deposition of vanadium oxide. An improvement in the optical properties (redshift in UV-Vis spectra) of TNTs and TNT/VO was noted. The photocatalytic activity was improved with increasing tube diameter, while it was weakened after the deposition of VO. Furthermore, photoactivity was investigated in photodiodes based on TNTs or TNT/VO and single crystals of CH3NH3PbI3. The photoelectric measurement revealed that different TNT diameters did not influence the I-V characteristic of the photodiodes, while the deposition of VO improved the photocurrent for smaller TNTs.

In this study, we report the influence of vanadium oxide (VO), as a photosensitive component, on the photoactivity of TiO2 nanotubes (TNTs). A series of TNTs of varying tube diameter were synthesized by the anodization of titanium foils at different voltages, while vanadium oxide was deposited on TNTs by wet chemical deposition. An improvement in the optical properties of nanotubes was observed after the deposition of vanadium oxide. An improvement in the optical properties (redshift in UV-Vis spectra) of TNTs and TNT/VO was noted. The photocatalytic activity was improved with increasing tube diameter, while it was weakened after the deposition of VO. Furthermore, photoactivity was investigated in photodiodes based on TNTs or TNT/VO and single crystals of CH3NH3PbI3. The photoelectric measurement revealed that different TNT diameters did not influence the I-V characteristic of the photodiodes, while the deposition of VO improved the photocurrent for smaller TNTs.

The controllable synthesis of rutile TiO2 single crystal particles with the preferential orientation of {111} facets still remains a scientific and technological challenge. Here, we developed a facile route for fabrication of rutile TiO2 nanorod crystals (RTiO2NRs) having high ratios of oxidative {111} to reductive {110} surfaces. RTiO2NRs were synthesized using a peroxo-titanium complex (PTC) approach, which was controlled by changing the Ti/H2O2 ratio. The thus obtained RTiO2NRs revealed a high tendency to agglomerate through orientation-dependent attachment along the {110} facets. This resulted in an increased {111}/{110} surface ratio and led to a markedly improved photocatalytic activity of RTiO2NR aggregates. The reported findings illustrate the rich potential of the herein proposed facile and energy-efficient synthesis of nanostructured rutile TiO2-based photocatalysts.

The controllable synthesis of rutile TiO2 single crystal particles with the preferential orientation of {111} facets still remains a scientific and technological challenge. Here, we developed a facile route for fabrication of rutile TiO2 nanorod crystals (RTiO2NRs) having high ratios of oxidative {111} to reductive {110} surfaces. RTiO2NRs were synthesized using a peroxo-titanium complex (PTC) approach, which was controlled by changing the Ti/H2O2 ratio. The thus obtained RTiO2NRs revealed a high tendency to agglomerate through orientation-dependent attachment along the {110} facets. This resulted in an increased {111}/{110} surface ratio and led to a markedly improved photocatalytic activity of RTiO2NR aggregates. The reported findings illustrate the rich potential of the herein proposed facile and energy-efficient synthesis of nanostructured rutile TiO2-based photocatalysts.

An environmentally friendly analog of the prominent methylammonium lead halide perovskite, methylammonium bismuth bromide (MA3 Bi2 Br9 ), was prepared and investigated in the form of powder, single crystals and nanowires. Complete characterization via synchrotron X-ray diffraction data showed that the bulk crystal does not incorporate water into the structure. At the same time, water is absorbed on the surface of the crystal, and this modification leads to the changes in the resistivity of the material, thus making MA3 Bi2 Br9 an excellent candidate for use as a humidity sensor. The novel sensor was prepared from powder-pressed pellets with attached carbon electrodes and was characterized by being able to detect relative humidity over the full range (0.7–96% RH) at ambient temperature. Compared to commercial and literature values, the response and recovery times are very fast (down to 1.5 s/1.5 s).

The electro-physical properties of raw, alkali and oxidatively modified jute fabrics were investigated as complex phenomena of the interactions between the fabrics’ chemical composition, carboxyl group content, crystallinity, structural characteristics, moisture sorption, and frequency of the electric field. At 80% relative air humidity, chemically modified jute fabrics have 38–179% and 1.7–5.4 times higher dielectric loss tangent and effective relative dielectric permeability compared to unmodified. To further improve these properties, fabrics were treated with CuSO4 and Cu-based nanoparticles were in situ synthesized on their surfaces by reduction. A few smaller agglomerates of Cu-based nanoparticles were observed across the alkali modified fabric's surface, while smaller irregularly shaped and larger agglomerates were distributed over the oxidatively modified fabric's surface. Regardless of the type of synthesized nanostructures (metallic Cu, copper oxide (Cu2O or CuO) or their mixtures), excellent fabrics’ effective relative dielectric permeability is guaranteed. Precisely, exploitation in specific conditions that contribute to copper reduction will make jute fabrics able to store 21–163 times more energy from an external electric field than before the exploitation, which will extend their lifetime. On the other hand, with increasing the total content of Cu after the reduction and formation of agglomerates of Cu-based nanoparticles, the movements of cellulose, hemicelluloses, and lignin molecules become difficult resulting in lower energy dissipation within the chemically modified than within unmodified fabric. Applied chemical modification and coating with Cu-based nanoparticles enables designing fabrics with predictable electro-physical properties, which is very important from the application point of view.

An environmentally friendly analog of the prominent methylammonium lead halide perovskite, methylammonium bismuth bromide (MA3 Bi2 Br9 ), was prepared and investigated in the form of powder, single crystals and nanowires. Complete characterization via synchrotron X-ray diffraction data showed that the bulk crystal does not incorporate water into the structure. At the same time, water is absorbed on the surface of the crystal, and this modification leads to the changes in the resistivity of the material, thus making MA3 Bi2 Br9 an excellent candidate for use as a humidity sensor. The novel sensor was prepared from powder-pressed pellets with attached carbon electrodes and was characterized by being able to detect relative humidity over the full range (0.7–96% RH) at ambient temperature. Compared to commercial and literature values, the response and recovery times are very fast (down to 1.5 s/1.5 s).

A facile synthesis was employed for three polyhedral oligo silsequioxanes (POSS), obtaining incompletely condensed structures with fern-like and cubic morphologies. Proton nuclear magnetic resonance spectroscopy (H-1 NMR) indicated the successful synthesis of the proposed POSS structures. The hydroxyl groups affected the manner and type of POSS morphology, as seen under a scanning electron microscope (SEM) and a transmission electron microscope (TEM). Fourier-transform infrared spectroscopy (FTIR) showed the availability of surface hydroxyl groups that contributed to the formation of a higher amount of char residue, as found from TGA analysis. The highest decomposition temperature (281 degrees C) and the least char residue were found for a cross-linkable POSS, obtained by esterification of the hydroxyl groups with methacryloyl chloride.

A novel adsorbents, 6-arm amino polyethylene glycol functionalized multiwall carbon nanotubes (PEG/MWCNT) loaded with alpha-FeOOH (Fe/PEG/MWCNT), and hybrid alpha-FeOOH/alpha-MnO2 nano-deposit (Fe-Mn/PEG/MWCNT) were used for As(V) removal. In a batch test, the influence of pH, contact time, initial ion concentration and temperature on adsorption efficiency was studied. Time-dependent adsorption was best described by pseudo-second-order kinetic model and Weber-Morris model which predicted intra-particle diffusion as a rate controlling step of overall process. Competitive kinetic study in the presence of interfering ions shows low detrimental effect on both capacity and kinetic of As(V) removal. Thermodynamic parameters showed that the adsorption was spontaneous and endothermic processes. Influences of the pH, iron oxide loading and interfering ions were modeled by using Visual MINTEQ software. High adsorption capacities: 49.39 and 59.78 mg g(-1) were obtained for Fe/- and Fe-Mn/PEG/MWCNT, respectively, and multi-cycle reusability indicated high applicability of obtained material. Two step removal process, in a batch study, was successfully performed by using PEG/MWCNT for cations removal in the first step, and Fe or Fe-Mn/PEG/MWCNT for As(V) removal in the second.

A novel adsorbents, 6-arm amino polyethylene glycol functionalized multiwall carbon nanotubes (PEG/MWCNT) loaded with alpha-FeOOH (Fe/PEG/MWCNT), and hybrid alpha-FeOOH/alpha-MnO2 nano-deposit (Fe-Mn/PEG/MWCNT) were used for As(V) removal. In a batch test, the influence of pH, contact time, initial ion concentration and temperature on adsorption efficiency was studied. Time-dependent adsorption was best described by pseudo-second-order kinetic model and Weber-Morris model which predicted intra-particle diffusion as a rate controlling step of overall process. Competitive kinetic study in the presence of interfering ions shows low detrimental effect on both capacity and kinetic of As(V) removal. Thermodynamic parameters showed that the adsorption was spontaneous and endothermic processes. Influences of the pH, iron oxide loading and interfering ions were modeled by using Visual MINTEQ software. High adsorption capacities: 49.39 and 59.78 mg g(-1) were obtained for Fe/- and Fe-Mn/PEG/MWCNT, respectively, and multi-cycle reusability indicated high applicability of obtained material. Two step removal process, in a batch study, was successfully performed by using PEG/MWCNT for cations removal in the first step, and Fe or Fe-Mn/PEG/MWCNT for As(V) removal in the second.

The influence of modification and vacuum/supercritical CO2 (scCO(2)) drying methods on the surface properties, morphology and thermal stability of cellulose nanocrystals (NC) was presented in this study. Introduction of reactive vinyl groups on NC surface was performed by either direct esterification with oleic acid, linseed or sunflower oil fatty acids; or by amidation of maleic acid/ethylene diamine with methyl ester of fatty acid. Obtained modified NC (m-NC) were characterized using MR and Raman spectroscopy; and by determination of acid, iodine and ester values. Structural analysis of m-NC showed varieties of forms, from spongy to nanostructural non-uniform layered morphology with observable agglomeration, which confirmed morphology dependence on modification/processing methods Thermogravimetry-MS spectrometry showed different thermal stability and degradation pathways of NC/m-NC. Incorporation of 1 wt% of reactive m-NC in unsaturated polyester lead to high performance nanocomposites and contributed to increase of stress at break in the range from 76 to 93%.