Polypyrrole (PPy) and polypyrrole-carboxylic functionalized multiwall carbon nanotube composites (PPy/f-MWNT) were synthesized by in-situ chemical oxidative polymerization of pyrrole monomer on multiwall nanotubes. The effect of the magnetic field intensity from 0 to 10KG on the conductivity of the nanocomposites was studied. The Hall coefficient and Hall mobility of PPy and PPy/ f-MWNT nanocomposite samples with different concentrations of MWNT were measured using the Van der Pauw technique in the same magnetic field range. The mobility decreased slightly with the increasing magnetic field, while the conductivity is dominated by a gradual increase in carrier density. The conductivity values demonstrate the utility of these complex composites as photovoltaic materials. With increasing CNT content, the measured magnetoresistance of the samples became more negative, which supports the fact that the average localization length of the nanocomposite materials is increased, and the charge transport is dominated by the MWNTs. Manuscript profile

It has been found that semiconductor nanocomposites have good photocatalytic behavior and can be used for the photodegradation of organic pollutants in water waste. ZnO, one of the eco-friendly semiconductor materials, was chosen to form a nanocomposite with graphene oxide. Graphene oxide in ZnO-based nanocomposites improves the photoactivity and photostability of ZnO. To prepare the graphene oxide, the Hummers method was used, then ZnO/GO nanocomposite was synthesized by hydrothermal method. The nanocomposites were annealed at different temperatures of 300 °C, 400 °C, and 500 °C. Raman spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR) confirmed the structure of synthesized graphene oxide nanosheets. Structural characterization of the nanocomposites was investigated using X-ray diffraction, Transmission Electron Microscope (TEM), and Field Emission Scanning Electron Microscope (FE-SEM). X-ray diffraction patterns of nanocomposites demonstrate that the annealed sample at 300 °C has better crystallinity than the other samples and was used to investigate the photocatalytic process. Photocatalytic experiment of the ZnO/GO was carried out by degradation of methylene blue using a laboratory-made reactor in alkaline, acidic, and neutral solutions. Photodegradation results were revealed that the maximum percent degradation of 87% was achieved in the alkaline solution. Manuscript profile

در این پژوهش، نانوذره های CdO با روش کاهش شیمیایی در شش دمای متفاوت تهیه شده اند. به دلیل تغییر دمای کلسینه‎شدن، نانوذره های CdOدر شش اندازه متفاوت تهیه شده اند. ویژگی های ساختاری و نوری نانوذره ها با پراش پرتو ایکس (XRD) و طیف‎سنجی مرئی-‎فرابنفش (UV-Vis) بررسی شده اند. برپایه تجزیه‎های انجام‎شده، نانوذره های کادمیم اکسید دارای ساختار مکعبی بوده و میانگین اندازه ذره ها 27 الی 60 نانومتر محاسبه شده است. برای بررسی رفتار فوتوکاتالیستی نانوذره ها، تخریب رنگ و رنگبری متیلن‎بلو درحضور نانوذره های کادمیم اکسید تحت تابش فرابنفش به‎صورت تابعی از زمان با pH های متفاوت در یک واکنشگاه ناپیوسته بررسی شده است. بررسی طیف های جذب نوری مرئی-‎فرابنفش نشان داد که میزان جذب نوری محلول در معرض پرتو فرابنفش به‎صورت تابعی از زمان کاهش یافته است. واکنش فوتوکاتالیستی نشان داد که تخریب رنگ و نرخ رنگ‎بری با افزایش سطح pH شتاب می گیرد. Manuscript profile