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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.

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).