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Purpose Over the past decades, intense efforts have been devoted to design and synthesize efficient photocatalysts which are active under sunlight for environmental and energy applications. Titanium dioxide (TiO2) has attracted much attention over many years for organic contaminant degradation in air or water due to its strong optical absorptivity, chemical stability and low cost. However, TiO2 has a very low photo quantum yield which prompts the easy recombination of photogeneration electron/hole pairs. In addition, bandgap of 3.2 eV restrains application of this photocatalyst mainly to the UV range. Design/methodology/approach Vertically oriented one-dimensional TiO2 nanostructures remarkably improve electron transport by creating a direct conduction pathway, decreasing intercrystalline contacts and stretching grown structure with the specified directionality. In this research, to enhance the visible light absorbance of TiO2, prearranged hydrogenated titanium dioxide nanorods (H-TNRs) in the presence of H2/N2 gas flow are hydrothermally synthesized. Findings The X-ray diffraction patterns illustrated the characteristic peaks of tetragonal rutile TiO2 and confirmed that there is no phase change after hydrogenation. Trivalent titanium ions surface defects and oxygen vacancies were considered as major reasons for redshift of absorption edge toward visible region and subsequently narrowing the bandgap to 2.27 eV. The optimized photocatalysts exhibited high visible-light-driven photocatalytic activity for degradation of methylene blue in water within 210. The synthesized H-TNRs established themselves as promising photocatalysts for organic compounds degradation in the aqueous solution. Originality/value To the best of the authors’ knowledge, this work is original and has not been published elsewhere nor is it currently under consideration for publication elsewhere.

Controllable synthesis of Metal-organic frameworks (MOFs) with well-defined morphology, composition and size is of great importance towards understanding their structure-property relationship in various applications. Herein, the effect of morphology of photocatalysts on their optical behavior and photocatalytic efficiency was identified utilizing physical synthetic parameters for methylene blue removal. For this purpose, MIL-53(Fe) was fabricated as an efficient photocatalyst via solvothermal approach using chloride and nitrate salts as different secondary block unit (SBU) sources. Each of the powders obtained by two metal sources was synthesized at three different temperatures (120, 150, and 180 ºC). The fabricated MOFs were methodically investigated and characterized in terms of structural, textural, morphological and optical. The obtained empirical data confirmed that the particles synthesized at 120 ºC using iron chloride exhibit the highest efficiency for methylene blue removal. This could be associated to their high surface area and UV light absorption in comparison with other samples. These results can be considered in future research to maximize degradation of organic dyes as a serious pollutant in wastewater.

We report the design and one-pot synthesis of Ag-doped BiVO4 embedded in reduced graphene oxide (BiVO4:Ag/rGO) nanocomposites via a hydrothermal processing route. The binary heterojunction photocatalysts exhibited high efficiency for visible light degradation of model dyes and were correspondingly used for the preparation of photocatalytic membranes using polyvinylidene fluoride (PVDF) or polyethylene glycol (PEG)-modified polyimide (PI), respectively. The surface and cross-section images combined with elemental mapping illustrated the effective distribution of the nanocomposites within the polymeric membranes. Photocatalytic degradation efficiencies of 61% and 70% were achieved after 5 h of visible light irradiation using BiVO4:Ag/rGO@PVDF and BiVO4:Ag/rGO@PI (PEG-modified) systems, respectively. The beneficial photocatalytic performance of the BiVO4:Ag/rGO@PI (PEG-modified) membrane is explained by the higher hydrophilicity due to the PEG modification of the PI membrane. This work may provide a rational and effective strategy to fabricate highly efficient photocatalytic nanocomposite membranes with well-contacted interfaces for environmental purification.

Water-based polyurethane coatings give a soft feeling for surface engineering for advanced wear- and friction-resisted purposes. In this work, we synthesized three types of polyols from castor oil applying short- and high-efficiency method for potential soft coating uses, as an appropriate alternative for methods that use a rotary evaporation and a vacuum oven in polyol synthesis. Castor oil was epoxidized in the presence of two types of catalysts, i.e. γ-alumina (ECOAl) and formic acid (ECOF). Although we could not detect unwelcome reactions taking place in the reaction chamber that should reduce the content of oxirane oxygen, the relative percentages of double bond conversion to oxiran for ECOAl and ECOF were theoretically 96% and 74%, respectively. Ring opening reaction of ECOAl was performed by two types of saponified castor oil utilizing Dean–Stark trap, an appropriate alternative for methods that use a rotary evaporation and a vacuum oven in polyol synthesis. The synthesized polyols were characterized by FTIR (ATR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), viscometer and OH number evaluation. Different weight percentages of the polyol samples having Tg values of ca. -6.5 °C and OH number of 6.2 were applied in synthesis of water-based polyurethane (WPU). It was found that WPU with 40 wt.% polyol has a minimum particle size and minimum poly dispersity index. WPU with 60 wt.% polyol exhibited the highest molecular weight, while it had the lowest viscosity, water absorption, glossiness, hardness, adhesion and Tg. By such structural manipulations we provided a basis for enhancement of properties of coatings for future works.

A castor oil-based fatliquoring agent for use in leather coating was prepared via Pickering emulsions stabilized by metal–organic frameworks (MOFs). The partially oxidized ZIF-8 (POZIF-8) nanoparticles were used as MOF in the presence of a castor oil-based dispersant. The results of the stability test showed that the presence of POZIF-8 nanoparticles leads to a stable oil/water emulsion with higher oil content than other nanoparticles, such as TiO2 and ZnO. The stabilized structure of the prepared fatliquoring agent was characterized by transmission electron microscopy (TEM). TEM image indicated that the castor oil either was surrounded or was encapsulated by MOF. The prepared fatliquoring agent was applied to the leather. Then, in order to prove the existence of POZIF-8 nanoparticles in collagen fibers, the cross section of the fatliquored leather was examined by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). These analyses revealed the good dispersion of POZIF-8 nanoparticles from grain to flesh side. The physical and mechanical properties of the fatliquored leather were compared with those of the control leather sample, which was fatliquored by a conventional agent. The results show that the prepared fatliquoring agent significantly improved mechanical properties, lightfastness, softness, and fullness of leather.

Chalcostibite copper antimony sulfide (CuSbS2) micro- and nanoparticles with a different shape and size have been prepared by a new approach to hot injection route. In this method, sulfur in oleylamine (OLA) is employed as a sulfonating agent providing a simple route to control the shape and size of the particles, which enables the optimization of CuSbS2 for a variety of applications. The sulfur to metallic precursor ratio appears to be one of the most effective parameters along with the temperature and time for controlling the size and morphology of the particles. The growth mechanism study shows in addition to the CuSbS2 phase the presence of not previously observed intermediate phases (stibnite (Sb2S3) and famatinite (Cu3SbS4)) at the initial stage of the reaction. By increasing the ratio of sulfur to copper and antimony, wider and thinner CuSbS2 particles are obtained. The particles have nanoplate and nanosheet morphology with a good shape and size uniformity. Coalescence of very thin nanosheets occurs with increasing reaction time eventually leading to formation of thicker particles which can be called nanobricks. Band gap determinations demonstrate that the obtained CuSbS2 particles have both direct (1.51–1.57 eV) and indirect (1.44–1.51 eV) bandgaps. Transmission Electron Microscopy (TEM) studies revealed that the preferred growth directions are along the basis axes of the unit cell ( [ 100 ] and [ 010 ] ). Optical and structural properties of the obtained CuSbS2 particles are indicative for their great potential in different generations of solar cells and supercapacitor applications.

Single crystalline platelet chalcostibite (CuSbS2) particles with good shape and size uniformity were successfully prepared using a hot injection method. In this synthesis, sulfur powder in oleylamine (OLA) was employed as a sulfonating agent. The synthesized CuSbS2 had an orthorhombic structure with a plate-like morphology. Selected area electron diffraction (SAED) patterns confirmed their single crystal nature. Band gap calculation from diffuse reflectance data revealed that it had both direct and indirect band gaps of 1.52 eV and 1.46 eV, respectively. Moreover, valence band (VB) and conduction band (CB) positions were determined by cyclic voltammetry (CV) characterization. Optical and structural properties of CuSbS2 indicate its potential applicability for solar cell applications. (C) 2017 Elsevier B.V. All rights reserved.

Chalcostibite copper antimony sulfide (CuSbS2) is a promising candidate for application in solar cells. The functionality of CuSbS2 particles depends on particle size and morphology and controlling these two parameters during synthesis is of utmost importance. In this study, CuSbS2 particles were prepared by a facile heat-up synthesis method utilizing sulfur powder (Su) and thiourea (Tu) to investigate the effect of the sulfur source on the structural and physical properties of CuSbS2 particles. Different morphologies were observed when Su and Tu were employed. The results demonstrated that the shape uniformity can be improved by applying a coordinating sulfur precursor (Tu). Moreover, nanoplatelet- and nanobrick-shaped particles were obtained by changing the ligand chemistry, i.e., by using a different combination of oleylamine (OLA), 1-octadecene (ODE), and oleic acid (OL). Band gap calculations showed that CuSbS2 had direct and indirect bandgaps with a small difference of 0.2 eV. Composition analysis of samples obtained from the Tu precursor revealed that antimony contents varied resulting in differences of the lattice parameter c. Moreover, valence band (VB) and conduction band (CB) positions determined by cyclic voltammetry (CV) suggested that this material based on its composition can have dual applications: first, as an absorber in nanocrystalline solar cells and second, as a hole transport material in perovskite solar cells.

We report an advanced method for the self-organization of an optomagnetic nanocomposite composed of both fluorescent clusters (ZnS quantum dots, QDs) and magnetic nanoparticles (CoFe2O4). ZnS nanocrystals were prepared via an aqueous method at different temperatures (25, 50, 75, and 100 degrees C). Their structural, optical and chemical properties were comprehensively characterized by X-ray diffraction (XRD), UV-vis, photoluminescence (PL) spectroscopy, scanning electron microscopy (SEM), dynamic light scattering (DLS), transmission electron microscopy (TEM), and infrared spectroscopy (FT-IR). The highest PL intensity was observed for the cubic ZnS nanoparticles synthesized at 75 degrees C which were then stabilized electrosterically using thioglycolic acid. The photophysical analysis of the capped QDs with a particle size in the range 9-25 nm revealed that the emission intensity and the optical band gap increases compared to uncapped nanocrystals (3.88 to 4.02 eV). These band gaps are wider than that of bulk ZnS resulting from the quantum confinement effect. Magnetic nanoparticles were synthesized via a co-precipitation route and a sol-gel process was used to form the functionalized, silica-coated CoFe2O4. Finally, thiol coordination was used for binding the QDs to the surface of the magnetic nanoparticles. The fluorescence intensity and magnetic properties of the nanocomposites are related to the ratio of ZnS and CoFe2O4. An optomagnetic nanocomposite with small size (12-45 nm), acceptable saturation magnetization (about 6.7 emu g(-1)), and satisfactory luminescence characteristics was successfully synthesized. These systems are promising candidates for biological and photocatalytic applications.

An eco-friendly H 2 ZrF 6 -based conversion coating reinforced by nanoceramic metal oxide particles was used as a protective layer for cold-rolled steel (CRS) substrates. Initially, the pH and temperature of the solution were optimized and then the effects of immersion time as the most effective process parameter on anti-corrosion performance and morphological properties were studied. On this basis, comprehensive analyses such as potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectrum (EDS) and atomic force microscopy (AFM) were used. Results showed the best anti-corrosion performance with the highest polarization resistance occurred when the pH and temperature of solution and immersion time were considered 4, 25 °C and 90 s, respectively. Uniform distribution of Zr along the surface of all treated samples was observed. FE-SEM images revealed that for the samples treated longer than 120 s, cracked morphology was evident.

Two supplementary approaches in terms of thermal degradation kinetics and Taguchi's experimental design were employed toward developing a design effort for intumescent coatings. A model intumescent system including ammonium polyphosphate (APP), pentaerythritol (PER), melamine (MEL), thermoplastic acrylic resin and liquid hydrocarbon resin was chosen and then subjected to thermogravimetric analysis and heat insulation tests to provide experimental data. Kinetic analysis of the thermogravimetric data based on the Friedman and Kissinger methods revealed that activation energy (Ea) and reaction order (n) could be used as parameters to accurately judge whether the selected intumescent components represented coordinated thermal characteristics. Examination of the calculated Ea and n values showed that the decomposition of thermoplastic acrylic resin and liquid hydrocarbon resin occurred first and that the APP, PER and MEL components were degraded immediately after. Such a degradation sequence was quite consistent with the functional mechanism of intumescent systems. In addition, simultaneous implementation of analysis of variance and mean effect assessment on the Taguchi data demonstrated that the designed formulation, based on the optimized coupling of 10 g MEL into APP/PER 25 g/11 g, exhibited the highest fireproofing time among the prepared coating samples. The APP content had the most important contribution to the flame retardant behaviour, and APP versus PER interactions showed the highest severity index. Scanning electron microscopy showed that the higher flame retardancy of the optimized sample was related to the presence of a large number of micropores in the expanded charring layer structure. Copyright © 2012 Society of Chemical Industry

CH3NH3SnIxCl3-x were synthesized at various synthesis temperatures. UV-Vis absorption portrays maximum absorption for the sample prepared at 120 ○C whose band gap (1.25 eV) is lower than Pb-based ones (1.55 eV).

ZnS QDs were synthesized via aqueous method and growth process f crystals were kinetically studied. PL results revealed that the growth kinetic involves two steps in which Oriented Attachment and Ostwald Ripening are dominated mechanisms.

We report on the photovoltaic performance of AgI quantum dots sensitized solar cells. The assembled solar cells yielded a power conversion efficiency of 0.64% and a short-circuit current of 2.13 mA/cm2 under one sun illumination.