Iranian Journal of Materials Science and Engineering

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In this work, the effects of co-precipitation temperature and post calcination on the magnetic properties and photocatalytic activities of ZnFe₂O₄ nanoparticles were investigated. The structure, magnetic and optical properties of zinc ferrite nanoparticles were characterized by X-ray diffraction (XRD), vibrating sample magnetometry and UV–Vis spectrophotometry techniques.  The XRD results showed that the coprecipitated as well as calcined nanoparticles are single phase with partially inverse spinel structures. The magnetization and band gap decreased with the increasing of co-precipitation temperature through the increasing of the crystallite size. However, the post calcination at 500 °C was more effective on the decreasing of magnetization and band gap. Furthermore, photocatalytic activity of zinc ferrite nanoparticles was studied by the degradation of methyl orange under UV-light irradiation. Compare with the coprecipitated ZnFe₂O₄ nanoparticles with 5% degradation of methyl orange after 5 h UV-light light radiation, the calcined ZnFe₂O₄ nanoparticles exhibited a better photocatalytic activity with 20% degradation.

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In this work, we report the synthesis of silver decamolybdate, Ag₆Mo₁₀O₃₃, nanostructure by a simple mechanohemical process followed by calcination treatment using acetamide as driving agent. Morphological study by scanning electron microscopy (SEM) images revealed bundles of rods grown closely together with an average diameter of 92 nm for Ag₆Mo₁₀O₃₃ sample. Ni-substituted Ag₆Mo₁₀O₃₃ compound was prepared via introducing nickel cation to precursor system in mechanical milling step. The particle size decreased to 87 nm by incorporating nickel units in substituted polymolybdate. It was concluded that the suitable selection of reagents can direct solid phase reaction towards producing nanostructured products. This technique is easy and simple for preparation of various mixed metal oxides without using any solvents and or complex procedures. In addition, the photocatalytic activity of the prepared products was studied on the removal of 4-nitro phenol (4-NP) as organic pollutant from water. The obtained results were also discussed in detail.

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Copper oxide (CuO) nanostructure particles were prepared using KOH/NaOH catalyst by low cost precipitation method and characterized by powder X-ray diffraction (PXRD), scanning electron microscope (SEM) and energy dispersive X-ray spectra (EDX) analysis. The photocatalytic dye degradation study of pure CuO nanostructure particles are analysed against two azo dyes (Direct black 38 (Black-E) and Congo red) under ultraviolet (UV) and solar irradiation. The release of major active species (*OH) in the photocatalytic degradation by as prepared CuO nanostructure particles were investigated by photoluminescence (PL) spectra with two different excitation wavelength (325and 355nm). The band gap of CuO nanostructure particles was calculated from diffuse reflectance spectra. The photocatalytic effect of CuO nanostructure particles is confirmed from the UV – Vis and photoluminescence spectra and also, further confirmed from the kinetic studies under UV and solar radiations. The photocatalytic degradation results revealed that 16.35% and 7.5% of black E and Congo red dye was degraded under UV, while it was 47.2% and 17.6% under solar light. The influence of pH on the photodegradation and change in the reaction temperature under solar irradiation were also analysed

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We report a simple and practical approach for the easy production of superhydrophobic coatings based on TiO₂-SiO₂@PDMS. In this study, we used tetraethylorthosilicate (TEOS) and titanium tetraisopropoxide (TTIP) as a precursor for the sol-gel synthesis of SiO₂ and TiO₂, respectively. Afterward, the surface of nanoparticles was modified by 1,1,1,3,3,3-hexamethyldisilazane (HMDS) before being combined with polydimethylsiloxane (PDMS). The hydrophobic property of coatings was evaluated by static contact angle measurements. The phase composition and structural evolution of the coatings were examined by X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) analysis. It was shown that changing the weight ratio of the solution composition of the coating can affect the hydrophobicity of the surface. The best sample has shown a superhydrophobic property with a 153˚ contact angle which contained (75%TiO₂-25%SiO₂) and PDMS at a weight ratio of 1:1. Moreover, the results showed that the superhydrophobic coating retains its hydrophobic properties up to a temperature of 450 ˚C, and at higher temperatures, it converts to a super hydrophilic with a water contact angle close to 0 ˚. The SiO₂-TiO₂@PDMS coating degrades methylene blue by about 55% and was shown to be capable of photocatalytically decomposing organic pollutants.