Sharif Digital Repository

In this work, a novel photoactive cellulose-based hydrogel was prepared by simultaneous AgCl formation and entrapment inside Al (III) and Fe (III) cross-linked carboxymethyl cellulose beads. Physio-chemical and optical properties of the synthesized composites were well characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, elemental mapping, Fourier transform infrared (FTIR) spectroscopy, photoluminescence (PL), and diffuse reflectance spectroscopy (DRS). The photocatalytic activity of hydrogels was evaluated by the degradation of rhodamine B (RhB), as a model environmental pollutant. A comparative study showed that... 

Mordenite (MOR) nanocrystals were synthesized using the hydrothermal method. Sol–gel and deposition methods were utilized to modify the zeolite surface with TiO2 and then AgBr or AgCl particles. Photocatalysts were characterized by using X-ray diffraction, Brunauer–Emmett–Teller (BET), and scanning electron microscopy techniques. Activity was evaluated by photodegradation of Acid Blue 92 as an azo dye. The effect of silver halide deposition on the photocatalytic behavior of the prepared nanocomposites was studied under both ultraviolet (UV) and visible light, and the results were compared. The results showed that AgCl/TiO2/MOR was more active under UV, while with visible source,... 

In this work, we report the synthesis of silver decamolybdate, Ag6Mo10O33, nanostructure by a simple mechanochemical 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... 

In this investigation, we have studied the kinetics and mechanism of photocatalytic conversion of methane into methanol reaction over the MoO 3(010) surface using a computer simulation method. Methane and oxygen as the reactants are used at room temperature and atmospheric pressure under UV photoirradiation of the catalyst. According to our data analysis, the order of methanol formation reaction with respect to CH4 and O 2 was determined to be l = 0.30 and m = -1.03, respectively. The highest methanol formation rate (TOF) value was obtained at about 0.05 molecule/s.site in a range of 25-35 W/cm2 incident light intensity with energy hv ≥ Eg. The selectivity of CH3OH was increased with... 

Zeolite-based photocatalysts were prepared by the sol-gel and deposition methods. The photocatalysts were characterised by X-ray diffraction, nitrogen adsorption-desorption isotherms, FTIR spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectrometry. The activity of the prepared photocatalysts was evaluated by the UV-induced degradation of acid blue 92, a textile dye in common use. The effect of various parameters, such as catalyst concentration, initial dye concentration, thiosulphate concentration and pH, on the rate and efficiency of the photocatalytic degradation of acid blue 92 was investigated. The results showed that each parameter influenced the degradation... 

Reduced graphene oxide (RGO) was used to improve the hydrogen sensing properties of Pd and Pt-decorated TiO2 nanoparticles by facile production routes. The TiO2 nanoparticles were synthesized by sol–gel method and coupled on GO sheets via a photoreduction process. The Pd or Pt nanoparticles were decorated on the TiO2/RGO hybrid structures by chemical reduction. X-ray photoelectron spectroscopy demonstrated that GO reduction is done by the TiO2 nanoparticles and Ti–C bonds are formed between the TiO2 and the RGO sheets as well. Gas sensing was studied with different concentrations of hydrogen ranging from 100 to 10,000 ppm at various temperatures. High sensitivity (92%) and fast response time... 

TiO2 nanoparticles (NPs) were synthesized by hydrothermal assisted sol-gel technique. In the next step, as-synthesized NPs were modified by poly ethylene glycol (PEG). Then, folic acid (FA) was conjugated to TiO 2-PEG. Finally, Doxorubicin (Dox) as an anticancer drug was loaded on as-prepared TiO2-PEG-FA nanocarrier. The optimization of TiO 2 and FA concentration and the influence of ultraviolet (UV) irradiation on photocatalytic activity of nanocarrier and Dox loaded carrier were assessed by utilizing the 3-(4,5-dimethylthiazol-2yl)-2,5- diphenyltetrazolium bromide (MTT)-assay method. Results indicated that the effect of NPs on cancer cells killing is dose-dependent, optimized at 1.25 g/L.... 

We report a simple and inexpensive synthesis route of TiO2 nanoparticles using electrical arc discharge between titanium electrodes in oxygen bubbled deionized (DI) water followed by heat treatment. The resulting nanoparticles were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD patterns demonstrate formation of TiO2 phase in oxygen bubbled water after heat treatment and dominance of rutile to anatase phase. The size and morphology of TiO2 nanoparticles were studied using different arc currents as a crucial parameter in properties of final... 

Herein, we report the preparation of SnS2 nanoflakes decorated with bismuth ferrite (BiFeO3) nanoparticles and reduced graphene oxide (rGO) nanosheets. The crystal structures and morphology results of composite indicated that spherical BiFeO3 nanoparticles were homogeneously attached onto the surface of SnS2 nanoflakes with the decoration of rGO sheets. The optimized photocatalyst, i.e. SnS2 (1.5)-BiFeO3/rGO (0.15) composite not only exhibites the highest photocatalytic performance for the degradation of methylene blue (MB) and Methyl orange (MO) as model reaction under visible light illumination among the individual SnS2 and BiFeO3 photocatalysts but also retains the stable photodegradation... 

Nanostructured aluminum titanate (AT) was synthesized by the sol-gel method. The calcination temperature was selected as a processing variable to obtain different phase ratios of AT and its parent phases i.e. TiO2 and Al2O3. The main aim behind the present work was to cast light on the photocatalytic performance of AT-based nanocomposites and evaluate their capability to serve as a novel photocatalyst. X-ray diffraction (XRD) analysis and field-emission scanning electron microscopy (FE-SEM) studies were conducted to evaluate the microstructure-sensitive properties of the synthesized powders. Diffuse reflectance spectroscopy (DRS) and the methylene blue degradation test were carried out to... 

ZnO/gC 3 N 4 hybrid nanofibers containing different concentrations of gC 3 N 4 nanosheets were prepared using electrospinning technique; this was followed by annealing at 460 forC for one hour in a box furnace. Based on scanning electron microscopy (SEM) image analysis, the mean diameter of the nanofibers was measured to be ~ 55 nm. Fourier transform infrared (FTIR) spectroscopy confirmed the presence of ZnO and gC 3 N 4 in the prepared nanofibers. The photocatalytic activity of the nanofibers was examined under UV photoirradiation, showing that the ZCN0.5 nanofibers containing 0.5 wt% of gC 3 N 4exhibited the highest performance, as compared to other photocatalysts. The observed improvement... 

We synthesized TiO2 nanoparticles by pulsed laser ablation of titanium target immersed in an aqueous solution of surfactant sodium dodecyl sulfate (SDS) or deionized water. The surfactant concentration dependence on size of TiO2 nanoparticles was investigated. The maximum amount of nanoparticles (with mean size of 40 nm in diameter) was obtained in an aqueous solution of 0.001 M SDS. We have also studied the effect of laser wavelength on growth of TiO2 nanoparticles. UV/visible spectroscopy and Scanning Electron Microscopy observations were employed for characterization of optical properties and particle sizes respectively. As TiO2 is a famous photocatalyst, we have also done photocatalytic... 

A new magnetic composite was synthesized by integration of ZnFe2O4 and MIL-53(Fe) micro-rods by a solvothermal method. This composite served as a heterogeneous catalyst to overcome the high electron-hole recombination rates of ZnFe2O4 and to enhance the degradation of Direct Red 23 under visible light irradiation. Different analytical techniques, including XRD, FTIR, SEM, DRS, VSM, and PL, were employed to characterize the synthesized heterojunction nanocomposite and to evaluate its photocatalytic activity. The ZnFe2O4/MIL-53(Fe)/Vis-light system resulted in significantly higher dye degradation as compared with pristine ZnFe2O4 and MIL-53(Fe) semiconductors at the optimum pH of 3.1 and... 

RGO/Ag/TiO2-nanotubes/Ti plates with high photocatalytic activity were fabricated via electrochemical reduction of graphene oxide on Ag/TiO2-nanotubes. The loading of silver nanoparticles was carried out by electroless reduction of Ag1+ onto TiO2 nanotubes previously formed by anodizing titanium. Microstructure studies show that reduced graphene oxide (RGO) layers having high surface area have been deposited on the as-prepared Ag/TiO2-nanotubes, where nanoparticles of Ag had grown on the walls of TiO2-nanotubes. The results of photocatalytic experiments demonstrate that the RGO/Ag/TiO2-nanotubes/Ti plate exhibits significantly enhanced photocatalytic activity for the photocatalytic... 

To enhance hydrophilicity and photocatalytic activity, N-doped and N–V-codoped TiO2films were coated on glass substrates by the sol–gel dip-coating method. The substrates were previously coated with SiO2using the same method. The coated samples, after annealing at 450 °C for 30 min in air, were analyzed by an X-ray diffractometer, scanning electron microscope, Fourier transform infrared spectroscope, X-ray photoelectron spectroscope, and UV–visible spectroscope. The SiO2/N–V-codoped TiO2photocatalyst showed a narrower band gap (2.93 eV) compared to the SiO2/N-doped. Degradation tests, methyl orange under UV light and stearic acid under visible light, were performed in order to evaluate... 

A green mechanochemical technique has been developed for the synthesis of mixed ammonium silver phosphomolybdate salt, (NH4)1.6Ag1.4PMo12O40.4H2O with sheet-like nanostructure. The reaction was prompted using acetamide/NH4NO3 at room temperature. The change of driving agent to urea at the same conditions led to an epitaxial growth of hierarchical microstructure of this polyoxoanion. The morphological and structural features of the prepared specimens were discussed in detail. The photocatalytic performance of the resulting nanosheets for removing 4-nitrophenol (4-NP) in water under visible light...