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Titanium dioxide exists in three different crystalline forms: anatase, rutile, and brookite. It is well known that on heating, anatase and brookite can be easily transformed to rutile which is considered as the most stable phase [1]. The aim of this study was to investigate the influence of different dopants on anatase-rutile phase transition. Doped TiO2 samples (TiO2-M, M = V, Mn, and Cu) containing 5 at% of the dopant were prepared by mixing anatase and appropriate oxide (V2O5, MnO2, and CuO) in agate mortar for 30 min. In order to determine the heat treatment conditions, TG/DTA analysis of the samples was performed. Finally, mixed powders as well as the pure anatase phase (TiO2) were heat treated at 700 °C for 3 h. XRD analysis was performed to estimate the phase composition, unit cell parameters, and crystallite sizes. Rutile was formed in all samples: 2.8 wt% in TiO2, 25.5 wt% in TiO2-Mn, 75.8 wt% in TiO2-V, and 95.2 wt% in TiO2-Cu. In TiO2- Mn, TiO2-V, and TiO2, anatase was present beside rutile, while in the case of TiO2-Cu 4.8 wt% of the unreacted CuO was found. Obtained results revealed that all the dopants accelerated anatase-rutile phase transition in the following order: Cu2+ > V5+ > Mn4+. It is well known that defects are the driving force for the anatase-rutile phase transition and since Ti4+ and Mn4+ are isovalent, no new defects were formed by incorporating Mn4+ ions into TiO2 lattice. This resulted in the least amount of rutile in TiO2-Mn comparing to TiO2-V and TiO2-Cu where new defects were probably formed. As no initial oxides were found in TiO2-Mn and TiO2-V, it can be concluded that Mn4+ and V5+ ions were incorporated into the anatase lattice. On the other hand, in the case of TiO2-Cu, even 4.8 wt% of initial CuO was found. The detected residue of CuO can be explained by the fact that the ionic radius of Cu2+ for an octahedral environment (0.870 Å) is much larger than that of Ti4+ (0.745 Å), unlike those for Mn4+ (0.670 Å) and V5+ (0.680 Å). Al

High-entropy spinel oxides (HESOs) are oxides with 5 or more cations with the general formula AB2O4 and the spinel ( Fd 3m ) structure. Due to their unique structure and properties, HESOs have shown great potential in various technological applications, i.e. they can be used as catalysts, adsorbents and photocatalysts. Since the first successful synthesis in 2018, researchers have been experimenting with different precursors and synthesis methods. However, further research is still needed in order to fully understand their capabilities and exploit their properties. The aim of this research is to synthesize novel HESOs using the self-propagating room temperature (SPRT) method, which is time and cost-effective and has not been utilized so far. Our results indicate that chlorides are not good precursors, since the formation of spinel structure has not been achieved. On the other hand, the use of nitrates has successfully led to a primary spinel ( Fd 3m ) phase. Still, certain issues persist, as secondary phases are commonly formed, especially in the presence of Mg or Cu. A potential solution that could ensure the formation of a single phase is the use of quenching from high temperatures (1000 °C), instead of gradual cooling.

N-doped TiO2/carbon composites (TiO2/CN) with different nitrogen content, were obtained starting from titanium isopropoxide and glucose, and by varying the amount of melamine, added to starting reaction mixture. For com­parison, an undoped sample (TiO2/C) was also prepared. Structural and surface characteristics were determined through scanning electron microscopy, thermo­gravimetric analysis, elemental analysis, Fourier transform infrared spectro­scopy, X-ray photoelectron spectroscopy, X-ray diffraction and nitrogen ads­orption–desorption isotherms. The photocatalytic activity of TiO2/CN com­posites was examined via photocatalytic degradation of methylene blue and multiclass pharmaceuticals from water solution. It was found that N doping of TiO2/carbon composites induced changes in structural and surface character­istics of TiO2/CN composites, improving their adsorption, but decreasing photocatalytic efficiency. Nevertheless, TiO2/CN0.05 composite obtained by the hydrothermal synthesis in the presence of glucose and 0.05 g melamine showed the highest efficiency for removing selected pharmaceuticals and methylene blue from aqueous solutions through the combined processes of adsorption in the dark, and photocatalytic degradation under UV and visible irradiation.

It is well known that titanium dioxide is usually used as a photocatalyst due to its nontoxicity, low cost, and stability. Conductive polymer, polypyrrole (PPy) is also appropriate for photocatalytic application being stable and easy to synthesize. The aim of this study was to obtain TiO2/PPy composites reaching higher photocatalytic efficiency compared to pure TiO2. Therefore, TiO2 was synthesized by the hydrothermal route, while PPy was obtained by the chemical oxidative polymerization method. TiO2/x% PPy nanocomposites (x = 0, 0.5, 1, 1.5, 3, 5 wt.%) were prepared by hand-mixing of powders in agate mortar for 30 min in order to find the optimal PPy content. Obtained materials were characterized by XRD, FTIR, TG/DSC, FESEM, and UV-Vis methods while their photocatalytic activity was estimated towards degradation of Reactive Orange 16 dye (RO16). A kinetic study was performed and a detailed mechanism of RO16 photocatalytic degradation in the presence of TiO2/PPy composites was proposed based on scavenger tests. The results showed that, despite PPy addition, TiO2 was present in anatase form in all samples with sufficiently small crystallites (around 26 nm) and preserved structure with no significant deviations in unit cell parameters. The band gap energy decreased with increasing of PPy content, from 3.14 eV for pure TiO2 to 2.94 eV for TiO2/5% PPy. All the obtained nanocomposites demonstrated higher photocatalytic activity than pure TiO2, whereby TiO2/1% PPy nanocomposite was the most efficient by degrading 99.6% of the dye for 105 min under simulated solar light. Therefore, the amount of 1 wt.% should be consider as optimal amount of PPy in a composite. It is established that the photodegradation of RO16 using TiO2/PPy nanocomposites follows pseudo-first kinetic order. RO16 photocatalytic degradation mechanism in the presence of TiO2/PPy nanocomposites can be well described by direct Z-scheme heterojunction which has never been reported for TiO2/PPy system.

Polyurethane networks (PUNs) based on hyperbranched polyesters (HBP), polycaprolactone (PCL), and isophorone diisocyanate were prepared.1,2 PUNs consist of different content of hard (HS) and soft segments (SS). The impact of the HBP and the content of the SS on the structure and viscoelastic properties of the prepared PUNs were investigated. XRD analysis confirmed that PUNs with lower SS content were amorphous, while samples with the highest SS content had a certain degree of crystallinity. Viscoelastic properties of PUNs depend on the SS content and used HBP. These PUNs have potential application as coatings.

Titan(IV)-oksid je jedan od najčešće korišćenih fotokatalizatora, dok za polipirol (PPy) postoje potvrde da je pogodan za ovu primenu. Cilj ovog rada bio je dobijanje kompozita TiO2/PPy sa boljom fotokatalitičkom aktivnosti u odnosu na TiO2. Kako bi se optimizovao sadržaj PPy u kompozitu, sintetisani su uzorci TiO2/x%PPy (x = 0, 0,5, 1, 1,5, 3, 5 mas.%), koji su okarakterisani TG/DTA, XRD, FTIR, FESEM i UV-Vis metodama, dok su njihova fotokatalitička svojstva ispitana kroz razgradnju tekstilne boje RO16. Nanokristalni TiO2 je dobijen u obliku anatasa veličine kristalita oko 2 nm, dok su izračunati parametri jedinične ćelije potvrdili da je kristalna struktura anatasa ostala nepromenjena nakon dodatka PPy. Gotovo svi uzorci (izuzev TiO2/3%PPy) su fotokatalitički aktivniji od TiO2, dok je TiO2/1%PPy pokazao najizraženiju fotokatalitičku aktivnost razgradivši 9 % boje nakon 75 min., Titanium(IV) oxide is one of the most used photocatalysts while polypyrrole (PPy) is a promising material for photocatalytic application. The aim of this work was to obtain TiO2/PPy composites exhibiting higher photocatalytic activity than TiO2. In order to determine the optimal PPy content in a composite, TiO2/x%PPy (x = 0, 0.5, 1, 1.5, 3, 5 wt.%) samples were synthesized and characterized by TG/DTA, XRD, FTIR, FESEM and UV-Vis methods, while the photocatalytic behavior was examined towards the degradation of the textile dye RO16. Nanocrystalline TiO2 was obtained in anatase form with crystallite size around 26 nm and preserved anatase crystal structure despite the addition of PPy according to the calculated unit cell parameters. Almost all samples (except TiO2/3%PPy) showed better photocatalytic activity than TiO2 while the best photocatalytic activity was demonstrated by TiO2/1%PPy which degraded 98 % of the dye after 75 min.

In this work, in order to improve the photocatalytic efficiency of ZnO, the optimal CeO2 content in ZnO powders was determined by varying the quantity of CeO2 from 0 to 10 mol%. The structural, microstructural, optical, textural, and photocatalytic properties of the hydrothermally obtained ZnO and CeO2/ZnO nanocomposites have been investigated by using the XRPD, FESEM, HRTEM/SAED, BET, and UV–Vis techniques. Detailed characterization revealed that CeO2, having spherical nanodots of about 5 nm with a large surface area, was distributed onto the ZnO surface, whose crystallites displayed a bimodal distribution, from nano-to micro-crystals. The morphology of ZnO is a combination of nanograins and microrods that further makes a 3-D tie-like morphology. The nanocomposite containing 5 mol% of CeO2 showed about 30% better photocatalytic efficiency in the degradation of Reactive Orange 16 dye compared to other samples under simulated solar radiation. In addition, the kinetics and mechanism of photocatalytic degradation were also proposed based on the photocatalytic activity and scavenger tests.

In this work, the decoration of noble metal nanoparticles on a semiconductor surface was used as a strategy to reach strong visible light absorption and efficient electron-hole separation to enhance the photocatalytic activity of ZnO. The Ag-modified ZnO nanopowders were obtained by the green synthesis. Zinc acetate dihydrate with different silver nitrate content (0, 0.75, 1.5 and 3 mol%) was dissolved in ethylene glycol in the presence of chitosan. The obtained mixtures in the form of gel were heated at 150 °C for 2 h and subsequently calcined at 400 °C for 1 h. The obtained samples were characterized by XRPD, FESEM, HRTEM, and UV-vis techniques while the photocatalytic efficiency was tested by monitoring the degradation of textile dyes Reactive Orange 16 (RO16), Acid Green 25 (AG25), Mordant Blue 9 (MB9), and Ethyl Violet (EV) then compared with the commercial ZnO nanopowder. The results showed that the Ag/ZnO samples consisted of ZnO nanoparticles with an average crystallite size of about 25 nm and Ag (20–30 nm) distributed on the surface of ZnO. The uniformity in size and nearly spherical shape of ZnO nanoparticles, forming various forms of agglomerates, were observed. Compared to both, the unmodified and commercial ZnO, all the prepared Ag/ZnO composites showed a broad band in the visible region at 500 nm, resulting in a narrowing of the band gap. This band confirms the surface plasmon resonance of the metallic Ag nanoparticles, since they can absorb visible light and activate the photocatalyst in the visible spectrum. All the obtained nanopowders showed higher adsorption power and photocatalytic activity in the degradation of RO16 dye than the commercial ZnO. The powder with 1.5 mol% of Ag had the highest photocatalytic efficiency as a consequence of smaller Ag particles and their good distribution, as well as the narrowest band gap. This means that the photocatalytic activity does not depend on the Ag content only and that the size and distribution of the met

A biphasic [Mn(dipya)(H2O)4](tpht)/{[Zn(dipya)(tpht)]·H2O}n com­plex material, I (dipya = 2,2’-dipyridylamine, tpht2– = dianion of terephthalatic acid) was synthesized by ligand exchange reaction and characterized by XRPD and FTIR spectroscopy. A ZnO/ZnMn2O4 composite, II, has been prepared via thermal decomposition of I in an air atmosphere at 450 °C. XRPD, FTIR and FESEM analyses of II revealed the simultaneous presence of spherical nano­particles of wurtzite ZnO and elongated nanoparticles of spinel ZnMn2O4. The specific surface area of II was determined by the BET method, whereas the volume and average size of the mesopores were calculated in accordance with the BJH method. The measurements of the mean size, polydispersity index and zeta potential showed colloidal instability of II. Two band gap values of 2.4 and 3.3 eV were determined using UV–Vis diffuse reflectance spectroscopy, while the measurements of photoluminescence revealed that II is active in the blue region of the visible spectrum. Testing of composite II as a pigmentary material showed that it can be used for the colouring of a ceramic glaze.

The influence of soft segment (SS) content on the properties of novel polyurethane networks (PUNs), prepared by a two-step polymerization in a solvent mixture, was investigated in this work. Hyperbranched polyester of the third pseudo generation (BH-30) was used as a crosslinker, and together with isophorone diisocyanate (IPDI) was applied to build hard segments (HS) in PUNs. On the other hand, SS of the prepared PUNs are based on polycaprolactone (PCL). The content of SS in PUNs varied from 10 to 50 wt%. The structural, thermal and mechanical properties, swelling behavior, as well as morphology of PUNs, were explored by various experimental methods. Performed investigations have shown that the use of BH-30 led to the emergence of relatively high crosslinking density and good mechanical properties, and that all features of PUNs significantly depend on the SS content. Higher PCL content caused presence of certain crystallinity, better thermal stability, more pronounced microphase separated morphology, but also lower degree of hydrogen bonding, crosslinking density and storage modulus of the prepared PUNs. The obtained results have shown that the properties of PUNs can be easily varied and customized to different practical needs.

N-doped TiO2/carbon composites (TiO2/CN) with different nitrogen content, were obtained starting from titanium isopropoxide and glucose, and by varying the amount of melamine, added to starting reaction mixture. For comparison, an undoped sample (TiO2/C) was also prepared. Structural and surface characteristics were determined through scanning electron microscopy, thermogravimetric analysis, elemental analysis, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and nitrogen adsorption–desorption isotherms. The photocatalytic activity of TiO2/CN composites was examined via photocatalytic degradation of methylene blue and multiclass pharmaceuticals from water solution. It was found that N doping of TiO2/carbon composites induced changes in structural and surface characteristics of TiO2/CN composites, improving their adsorption, but decreasing photocatalytic efficiency. Nevertheless, TiO2/CN0.05 composite obtained by the hydrothermal synthesis in the presence of glucose and 0.05 g melamine showed the highest efficiency for removing selected pharmaceuticals and methylene blue from aqueous solutions through the combined processes of adsorption in the dark, and photocatalytic degradation under UV and visible irradiation.

N-doped TiO2/carbon composites (TiO2/CN) with different nitrogen content, were obtained starting from titanium isopropoxide and glucose, and by varying the amount of melamine, added to starting reaction mixture. For comparison, an undoped sample (TiO2/C) was also prepared. Structural and surface characteristics were determined through scanning electron microscopy, thermogravimetric analysis, elemental analysis, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and nitrogen adsorption–desorption isotherms. The photocatalytic activity of TiO2/CN composites was examined via photocatalytic degradation of methylene blue and multiclass pharmaceuticals from water solution. It was found that N doping of TiO2/carbon composites induced changes in structural and surface characteristics of TiO2/CN composites, improving their adsorption, but decreasing photocatalytic efficiency. Nevertheless, TiO2/CN0.05 composite obtained by the hydrothermal synthesis in the presence of glucose and 0.05 g melamine showed the highest efficiency for removing selected pharmaceuticals and methylene blue from aqueous solutions through the combined processes of adsorption in the dark, and photocatalytic degradation under UV and visible irradiation.

Titan(IV)-oksid je jedan od najčešće korišćenih fotokatalizatora, dok za polipirol (PPy) postoje potvrde da je pogodan za ovu primenu. Cilj ovog rada bio je dobijanje kompozita TiO2/PPy sa boljom fotokatalitičkom aktivnosti u odnosu na TiO2. Kako bi se optimizovao sadržaj PPy u kompozitu, sintetisani su uzorci TiO2/x%PPy (x = 0, 0,5, 1, 1,5, 3, 5 mas.%), koji su okarakterisani TG/DTA, XRD, FTIR, FESEM i UV-Vis metodama, dok su njihova fotokatalitička svojstva ispitana kroz razgradnju tekstilne boje RO16. Nanokristalni TiO2 je dobijen u obliku anatasa veličine kristalita oko 2 nm, dok su izračunati parametri jedinične ćelije potvrdili da je kristalna struktura anatasa ostala nepromenjena nakon dodatka PPy. Gotovo svi uzorci (izuzev TiO2/3%PPy) su fotokatalitički aktivniji od TiO2, dok je TiO2/1%PPy pokazao najizraženiju fotokatalitičku aktivnost razgradivši 9 % boje nakon 75 min., Titanium(IV) oxide is one of the most used photocatalysts while polypyrrole (PPy) is a promising material for photocatalytic application. The aim of this work was to obtain TiO2/PPy composites exhibiting higher photocatalytic activity than TiO2. In order to determine the optimal PPy content in a composite, TiO2/x%PPy (x = 0, 0.5, 1, 1.5, 3, 5 wt.%) samples were synthesized and characterized by TG/DTA, XRD, FTIR, FESEM and UV-Vis methods, while the photocatalytic behavior was examined towards the degradation of the textile dye RO16. Nanocrystalline TiO2 was obtained in anatase form with crystallite size around 26 nm and preserved anatase crystal structure despite the addition of PPy according to the calculated unit cell parameters. Almost all samples (except TiO2/3%PPy) showed better photocatalytic activity than TiO2 while the best photocatalytic activity was demonstrated by TiO2/1%PPy which degraded 98 % of the dye after 75 min.

We present the synthesis and photocatalytic properties of mixed-phase TiO2 nanoparticles decorated with silver nanodots obtained by environmental-friendly wet chemical method using low molecular weight chitosan as the silver reducing agent. Structural analysis of synthesized Ag nanoparticles revealed that they crystallized in a rare hexagonal modification. High-resolution transmission electron microscopy study shows that lt 3-nm hexagonal-Ag nanoparticles are implanted on the surface of lt 20-nm anatase grains. Compared to Ag-free TiO2 powders, implantation with Ag results in important increase in visible light absorption. The photocatalytic activity of the samples was measured by monitoring decolorization of concentrated textile dye solution (50 mg L-1 of Reactive Orange 16) under simulated solar irradiation of 280 W m(-2). The optimum photocatalytic properties are achieved with 5 wt% of silver. Based on the collected results, the operating mechanism of the degradation process is suggested, and the effects of the silver addition are explained.

The properties of BaCe1-xInxO3-delta (x = 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, and 0.40) as proton conducting electrolyte are examined. The dense electrolyte is formed after sintering at 1300 degrees C for 5 h in air. The samples with In content > 25 mol% contain In2O3 as a secondary phase. The highest total conductivity is around 5x10(-3) S/cm for BaCe0.75In0.25O3-delta in the wet hydrogen atmosphere at 700 degrees C. After exposure to pure CO2 atmosphere at 700 degrees C for 5 h, the concentrations of at least 15 mol% In can completely suppress degradation of the electrolyte. The power density of Ni-BaCe0.75In0.25O3-delta/BaCe0.75In0.25O3-delta/LSCF-BaCe0.75In0.25O3-delta fuel cell tested in wet hydrogen atmosphere reaches 264 mW/cm(2) at 700 degrees C. This result is an indication of stability and functionality of this electrolyte and its versatility in respect to type of fuel and performing environment.

The impact of the type and amounts of nanofiller on the features of the glycidyl methacrylate-co-ethylene glycol dimethacrylate (GMA-co-EGDMA)/organomodified montmorillonite (OMt) nanocomposites that were prepared by in situ radical suspension polymerization, was examined. Cloisite 30B and Cloisite 25A were used in this study as nanofillers, in amounts of 2 and 10 wt.%. The structure, morphology, thermal stability and porosity of the initial GMA-co-EGDMA copolymer and their nanocomposites were examined by ATR-FTIR analysis, wide angle X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), transmission electron microscopy (TEM), thermogravimetric analysis (TG) and mercury porosimetry. It has been established that both clay nanofillers were successfully incorporated into the structure of the initial copolymer, simultaneously on their surface and also on cross-sectional area. Prepared samples with 2 wt.% have predominantly exfoliated, while samples with 10 wt.% have some tactoids-aggregates structure of the OMt layers. Thermogravimetric analysis revealed that after ~ 30 % of degradation, all nanocomposites become more thermal stable than the initial copolymer. The obtained results indicate that porosity parameters can be easily modified with the addition of clay nanofillers and thus prepared nanocomposites adjusted to specific purposes. © 2022 Authors. Published by association for ETRAN Society.

Bismuth ferrite is a unique multiferroic material that has a ferroelectric and antiferromagnetic order at room temperature. The rhombohedrally (R3c) distorted BiFeO3 perovskite structure is a result of relative cation displacement along [111] axis of the cubic perovskite structure and relative rotation of two oxygen octahedra in opposite directions around [111] axis [1]. The partial substitution of Bi3+ with rare-earth ions can affect the magnitude of lattice distortion and thus the value of electric polarization. The presence of undesirable secondary phases (Bi2Fe4O9 and Bi25FeO39) and structural point defects (oxygen and bismuth vacancies) in pure BiFeO3 lead to a high leakage current, which deteriorates its ferroelectric properties. Doping with rare-earth elements with large ionic radii is found to reduce the number of the structural defects and thus improve ferroelectric properties [2]. The influence of partial substitution of Bi3+ with La3+ and/or Eu3+ on ferroelectric properties of BiFeO3 ceramics was investigated. The Bi1-(x+y)LaxEuyFeO3 (x = 0, 0.025 0.05, 0.10; y = 0, 0.025, 0.05, 0.10) powders were synthesized by hydro-evaporation method, uniaxially pressed at 9 t/cm2 and sintered at 835 °C for 3 h. All the ceramic samples showed a rhombohedral structure, without presence of the secondary phases. Their morphology indicated the complete sintering under the given conditions. The grain size and grain shapes differed more depending on the dopant type and amount. The introduction of La3+ and/or Eu3+ at the site of Bi3+ led to such distortions within the rhombohedral lattice that resulted in much greater remnant electric polarization (Pr) in comparison with the undoped sample. The Bi1-(x+y)LaxEuyFeO3 ceramic samples with x+y = 0.10 showed approximately quadratic polarization vs. electric field P(E) hysteresis curves as well as significantly high values of pure ferroelectric polarization Pr, in large electric fields (100 – 140) kV/cm. The leakage currents of La3+

Dyes released from textile industries present a big threat to the environment, and remediation of wastewaters became one of the major scientific challenges. In recent years, there has been a great need for catalysts that would oxidize pollutants under dark ambient conditions without the use of external stimulants like light, temperature, or additional chemicals such as O3, H2O2. Efficient work of these catalysts would significantly reduce the energy consumption. Among other materials, perovskite-type oxides with general formula ABO3 emerged as possible catalysts for dye degradation in the dark conditions. Lanthanum nickelates with single (LaNiO3) and layered perovskite structure (La4Ni3O10, La3Ni2O7, La2NiO4) showed good catalytic properties, due to the existence of nickel in two oxidation states (Ni2+ and Ni3+) and the oxygen non-stoichiometry in these materials [1]. This study presents structural, microstructural and catalytic properties of the LaNi1-xNbxO3-based (xNb = 0.000, 0,005 and 0,010; La-Ni-Nb-O) powders prepared by mechanical activation method. The XRD (X-Ray Diffraction) analysis revealed the existence of a multiphase oxide system, including layered structures of nickelates Lan+1NinO3n+1 (n = 3, 2, 1, 0) and NiO phase in all La-Ni-Nb-O-based powders. Also, the HRTEM (High Resolution Transmission Electron Microscopy) analysis confirmed the presence of structural polytypes in these powders. The catalytic properties of La-Ni-Nb-O-based powders were investigated by degradation of the anionic azo dye, Reactive Orange 16 (RO16), under dark ambient conditions at different pH values (3, 6.5, 9.5 and 11) and temperature of 20 °C. The best catalytic efficiency in the degradation of RO16 dye showed the sample with x(Nb) = 0.010 in acidic solution, where the residual of RO16 dye was about 4.5 % after 330 minutes. The reusability test for this powder in degradation process of RO16 dye showed that the sample with x(Nb) = 0.010 retained its catalytic activity during t

Titanium dioxide is the most suitable semiconductor for photocatalytic application due to its high efficiency, increased stability, low-cost, and non-toxicity. However, it is possible to enhance the photocatalytic activity of TiO2 by homogenizing it with conductive polymers. One of the most attractive conductive polymers is polypyrrole (PPy) owing to its stability, low-cost, and special redox properties. The aim of this work was to obtain the TiO2/PPy nanocomposites with a higher photocatalytic activity compared to TiO2. In order to determine the optimal content of PPy, four TiO2/x%PPy samples (x = 0, 1, 3, and 5 wt.%) were synthesized and characterized by XRD and TG/DSC analyses. The photocatalytic activity was examined towards the degradation of toxic textile azo dye Reactive Orange 16. It was observed that an increase in PPy content led to better adsorption capacity of the synthesized nanocomposites. Samples TiO2/1%PPy and TiO2/5%PPy demonstrated better photocatalytic activity than TiO2, while TiO2/3%PPy showed very similar photocatalytic activity to TiO2. Near complete degradation of the dye (98 %) was reached in 75 min by using TiO2/1%PPy, comparing to pure TiO2, which degraded the same amount of the dye in 120 min. Considering all the obtained results, the optimal content of PPy in the composite for degradation of Reactive Orange 16 is 1 wt.%.

The structural, microstructural, optical and photocatalytic properties of hydrothermally obtained single-phase ZnO and CeO2@ZnO nanocomposites have been investigated by the XRPD, FESEM, HRTEM/SAED and UV-vis techniques. In order to improve the photocatalytic efficiency of ZnO, the optimal CeO2 content in ZnO powders was determined by varying the quantity of CeO2 from 0 to 10 mol%. The results showed that CeO2 with spherical crystallites of about 5 nm was distributed onto the ZnO surface, whose crystallites displayed a bimodal distribution, from nano- to microcrystallites. The morphology of ZnO particles varied from elongated nanograins to microrods that further formed a 3-D tie-like morphology which was disrupted by CeO2 adding. By degrading 90% of RO16 dye in 180 minutes, the composite containing 5 mol% of CeO2 showed approximately for 30% better photocatalytic efficiency comparing to other samples, although all the obtained powders have similar structural, microstructural and optical characteristics. This is obviously the optimal ratio of these two phases, in which synergy of CeO2 adsorption and ZnO photocatalytic effect reaches its maximum due to reduced recombination rate and improved adsorption. The kinetic of RO16 degradation could be described by a pseudo-first order model.

Poznato je da je titan-dioksid, kao netoksičan, stabilan i ekonomičan materijal, jedan od najčešće korišćenih fotokatalizatora. S druge strane, elektroprovodni polianilin (PANI) je takođe pogodan kandidat za primenu u fotokatalizi. Cilj ovog rada bio je dobijanje nanokompozita TiO2/PANI sa boljom fotokatalitičkom aktivnošću u odnosu na TiO2. U cilju optimizacije sadržaja polimera sintetisano je 4 uzorka TiO2/x%PANI (x = 0, 1, 3 i 5 mas.%), koji su okarakterisani XRD i TG/DTA metodama, dok je fotokatalitička aktivnost ispitana kroz razgradnju toksične tekstilne boje RO16. Pokazano je da su svi kompoziti fotokatalitički aktivniji od TiO2, i da optimalan sadržaj polianilina iznosi 3 mas.%. Naime, uzorak TiO2/3%PANI je, nakon 60 minuta, razgradio 95 % boje, što je za 17 % više u odnosu na TiO2, dok je nakon 120 minuta fotorazgradnja boje potpuna. Pored toga, ovaj uzorak je pokazao čak 14 puta izraženiju adsorpciju od TiO2. Efikasnost TiO2/5%PANI je slična TiO2/3%PANI, ali sa slabije izraženim adsorpcionim svojstvima, dok je efikasnost TiO2/1%PANI bliska TiO2., It is well known that the non-toxic, stable and economical titanium dioxide is one of the most commonly used photocatalysts. On the other hand, the conductive polyaniline (PANI) is also suitable candidate for photocatalytic application. The aim of this work was to obtain the TiO2/PANI nanocomposites with increased photocatalytic activity comparing to TiO2. In order to determine the optimal PANI content, four TiO2/x%PANI samples (x = 0, 1, 3 and 5 wt.%) were synthesized and characterized by XRD and TG/DTA analysis. The photocatalytic activity was tested on the toxic textile RO16 dye. It is shown that all the composites exhibited better photocatalytic performances than TiO2 and that the optimal PANI content amounted 3 wt.%. Namely, the TiO2/3%PANI degraded 95 % of the dye within 60 minutes, which is for 17 % better comparing to TiO2. The full photodegradation was reached in 120 min. This sample showed even 14 times better adsorption than TiO2. The efficiency of TiO2/5%PANI was similar to TiO2/3%PANI, but with poorer adsorption, while the efficiency of TiO2/1%PANI was close to TiO2.

A biphasic [Mn(dipya)(H2O)4](tpht)/{[Zn(dipya)(tpht)]·H2O}n complex material, I, (dipya = 2,2’-dipyridylamine, tpht2– = dianion of terephthalatic acid) was synthesized by ligand exchange reaction and characterized by XRPD and FTIR spectroscopy. A ZnO/ZnMn2O4 composite, II, has been prepared via thermal decomposition of precursor I in an air atmosphere at 450 °C. XRPD, FTIR and FESEM analyses of II revealed the simultaneous presence of spherical nanoparticles of wurtzite ZnO and elongated nanoparticles of spinel ZnMn2O4. The specific surface area of II was determined by the BET method, whereas the volume and average size of the mesopores were calculated in accordance with the BJH method. The measurements of the mean size, polydispersity index and zeta potential showed colloidal instability of II. Two band gap values of 2.4 and 3.3 eV were determined using UV–Vis diffuse reflectance spectroscopy, while the measurements of photoluminescence revealed that II is active in the blue region of the visible spectrum. Testing of composite II as a pigmentary material showed that it can be used for the colouring of a ceramic glaze.

A novel magnetic polymer/bentonite composite was prepared by suspension copolymerization of glycidyl methacrylate and ethylene glycol dimethacrylate in the presence of magnetic bentonite (MB-PGME) and functionalized with ethylene diamine and hexamethylene diamine (MB-PGME-ED and MB-PGME-HD). The obtained samples were characterized in terms of structure as well as thermal, magnetic and morphological properties. The sorption of rhenium (Re) and tungsten (W) from aqueous solution onto MB-PGME-ED and MB-PGME-HD was investigated considering their contact time and different initial ion concentration, giving possibility for usage of these composites as commercial sorbents. The sorption system follows the pseudo-second order and intraparticle diffusion kinetic models. The results indicated a better fit with the Freundlich isotherm model.

Zinc oxide nanoparticles (ZnO-NPs) have been a subject of numerous researches owing to their multifunctional properties in many applications, such as solar cells, UV light-emitting devices, gas sensors and photocatalysts. ZnO-NPs can be synthesized through various methods and their features can be tailored by shape and size, resulting in new applications relevant to their structural properties. The synthesis of ZnO-NPs via controlled thermal decomposition of the single-source precursors represents a novel synthetic methodology. The basic goal of this study was to investigate the influence of precursors on crystallite size and morphology of the resulting ZnO-NPs. Four structurally characterized Zn complexes with different benzenepolycarboxylato ligands [1] were used as precursors for investigation of photocatalytic and antimicrobial effects of thermally obtained ZnO-NPs. The XRPD and FESEM analysis of ZnO-NPs, prepared by thermolysis of Zn precursors at 450 °C in the air atmosphere, revealed hexagonal wurtzite structure (space group P63mc, a ≈ 3.25 and c ≈ 5.21 Å) with an average crystallite size in the range of 39–47 nm and similar morphology. The best photocatalytic activity for degradation of Reactive orange 16 dye has been observed for ZnO-NPs where crystallites form the smallest agglomerates. All obtained ZnO-NPs showed excellent inhibitory effect against Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli.

A novel magnetic polymer/bentonite composite was prepared by suspension copolymerization of glycidyl methacrylate and ethylene glycol dimethacrylate in the presence of magnetic bentonite (MB-PGME) and functionalized with ethylene diamine and hexamethylene diamine (MB-PGME-ED and MB-PGME-HD). The obtained samples were characterized in terms of structure as well as thermal, magnetic and morphological properties. The sorption of rhenium (Re) and tungsten (W) from aqueous solution onto MB-PGME-ED and MB-PGME-HD was investigated considering their contact time and different initial ion concentration, giving possibility for usage of these composites as commercial sorbents. The sorption system follows the pseudo-second order and intraparticle diffusion kinetic models. The results indicated a better fit with the Freundlich isotherm model.

In this study, the possibility to stabilize O-2 ion conductors in Bi2O3-V2O5 system was investigated. Six pseudo-binary Bi2O3-V2O5 mixtures [3.50 lt x(V2O5) lt 8.50 mol%] were thermally treated at 1000 degrees C for 1 h. The samples were characterized by XRD, HRTEM/SAED, DTA and EIS techniques. The high-temperature reaction between alpha Bi2O3 and V2O5 resulted in formation of microcrystalline single-phase specimens containing the phase based on delta-Bi2O3 if V2O5 content was >= 4.63 mol%. The obtained phases exhibited main diffraction peaks corresponding to the simple cubic delta-Bi2O3 (space group Fm-3m) but Rietveld refinement showed a threefold repeat on a simple cubic sublattice indicating that the true unit cell is 3x3x3 supercell. Within proposed supercell, the octahedrally coordinated V5+ ions fully occupy 4a Wyckoff position and partially occupy 32f. The Bi3+ ions are placed at the rest of 32f and at 24e and 48h with full occupation. In total, 22 % of anionic sites are vacant. The ionic conductivity of phase with the lowest dopant content, i.e. Bi103V5O167, amounts 0.283 S cm(-1) at 800 degrees C with the activation energy of 0.64(5) eV, which is comparable to the undoped delta-Bi2O3 known as the fastest ion conductor.