جستجوی مقالات مرتبط با کلیدواژه « نانومیله » در نشریات گروه « مواد و متالورژی »

In this research, the process of growth and the optimum length of ZnO nanorods has been studied as a subject of semiconductors, that are used in the photoelectrochemical solar cell made by Sol-Gel and Hydrothermal method.These Nano structures, having suitable gap, cause the decomposition of water into its constructing elements, hydrogen and oxygen.The most length of nanorods achieved by the FTO sublayer and deionized water solvent, at 95°C growth temperature, while 3 hours growing time, and on these conditions caused the length of nanorods to be 1500 nanometers, with the biggest length to width ratio 15.Also, at the final stage, photoelectrochemical experiments and the effects of nanorods length to the decompositionof water was studied. The results of photoelectrochemical experiments showed the optimum quantity for nanorods.The best result of photoelectrochemical has been reached to the maximum ratio of length to width 10, and the maximum length of nanorods 1000 nanometers that has been grown at the temperature of 95°C and during 2 hours.

In a few past years, finding efficient photocatalysts for direct harvesting and conversion of solar energy into clean hydrogen fuel or photodegradation of environmental pollution is one of the most important strategies to overcome energy constraints and environmental problems. The TiO2 photocatalyst has a high band gap and recombination rate and is active only in the UV range, which is a small part of the sun's spectrum. In order to dominate the limitations of this photocatalyst and improve its optical and electronic properties, many studies have been done, including the doping of various elements to change the energy level and band structure of TiO2. In this project, it was attempted to obtain hydrothermally prepared reduced titanium dioxide nanorods (RTNR) in the presence of hydrogen/ nitrogen gas flow. Reduced TiO2 nanorods have established themselves as a promising photocatalyst due to the creation of oxygen vacancies and surface disorder, consequently, the increase in absorption at visible spectrum and enhancement of the optical properties of the nanostructure.

In this paper, Structural, optical and photocatalytic properties of bismuth vanadate nanorods were studied. The bismuth vanadate (BiVO4) nanorods were made by thermal method in the presence of PEG (Polyethylene glycol) soft template. To study the nanorods, the X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS) and ultraviolet– visible spectroscopy (UV-Vis) were used. The X-ray diffraction pattern were indicated that the nanorods have a monoclinic structure and the results of XRD and EDS analysis showed that there did not any impurity element in nanorods. From the FESEM image, it was found that the average diameter and length of the nanorods are 37 and 439 nm, respectively. The UV-Vis analysis showed that the optical band gap of bismuth vanadate nanorods is 2.22 eV, which is in the visible light range. The photocatalytic activity of nanorods were evaluated by photodegradation of Congo red under visible light irradiation. According to the results of this research, bismuth vanadate nanorods with monoclinic structure is a good choice for the degradation of organic matter with sunlight. 

 In this research, nanostructured nickel molybdate (NiMoO4) active material was successfully synthesized by a simple hydrothermal route. Structural characterizations were performed using X-Ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR), and surface morphology of the as-prepared material was obtained by Field Emission Scanning Electron Microscopy (FESEM). The results showed that the as-prepared electrode material has a nanometric and rod-shaped structure and their crystal structure was β-phase. Electrochemical evaluations using cyclic voltammetry at various potential scanning rates and galvanostatic charge-discharge at various current densities show that nickel molybdate active material has the high specific capacitance of 730 F g-1 at a current density of 1 A g-1 and a capacity retention of about 63.2 % even with a 10-fold increase in current density to 10 A g-1. The obtained results imply that the as-synthesized NiMoO4 nanorods could be a promising candidate as electrode material for high performance supercapacitors.