Abstract: Flower-like birnessite-type MnO2 (Bir-MnO2) was synthesized through decomposition of KMnO4 under acid condition at 90 °C in open system. The addition of surfactant was a key factor for synthesis of Bir-MnO2 at low temperature and ambient pressure. Crystal nucleus obtained via reaction between surfactant and KMnO4 can catalyze decomposition of KMnO4, which led to the higher velocity of reaction. Reducibility of surfactant additional had an impact on yield and size of sample obtained. As-prepared sample with highest yield and smallest size was synthesized by using SOA as surfactant. Long reaction time and high reaction temperature were propitious to the growth of sample. The as-prepared samples were used to degrade rhodamine B (RhB), and the efficiency was different as the size of nanoflowers changed.
Abstract: The worm-like morphology of silver sulfide (Ag2S) was successfully prepared via hydrothermal reaction at 150°C by using silver nitrate (AgNO3) and thioacetamide(CH3CSNH2) as both the sliver sources and sulfur sources, β-cyclodextrin as the template agent, and water as the solvent. The worm-like of Ag2S are characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), x-ray photoelectronspectroscopy (XPS), energy dispersivex-ray (EDX), high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SEAD). Ultraviolet-visible spectra (UV-vis) and photoluminescencespectroscopy (PL) were used in an optical study of the products. The results showed that the existence of β-cyclodextrin is crucial to the formation of worm-like Ag2S, and the optoelectronics test results showed that the sample have a broad absorption in ultraviolet and visible light region.
Abstract: A rattle-type diamine-functionalized mesoporous silica sphere (DA-RMSS) was fabricated stepwise using a self-templating method through cationic surfactant assisted selective etching strategy. The rattle-type morphology of the obtained DA-RMSS material was disclosed by transmission electron microscopy, while its chemical composition was characterized by CHN elemental analysis, Fourier transform infrared spectroscopy, and solid-state 29Si cross-polarization/magic-angle-spinning nuclear magnetic resonance spectroscopic measurement, which corroborates the successful formation of siloxane network and the incorporation of organic component. Moreover, nitrogen adsorption–desorption isotherm measurement was conducted to reveal that DA-RMSS possesses large Brunauer–Emmett–Teller (BET) specific surface area of 814 m2g–1, pore volume of 0.78 cm3g–1, and narrow pore size distribution centered at 3.0 nm. Furthermore, its uptake property on carbon dioxide was also investigated in this contribution.
Abstract: Nanotechnology as a multidisciplinary and scientific innovation plays an important role in numerous biomedical applications, such as molecular imaging, biomarkers and biosensors and also drug delivery. A wide range of studies have been conducted on using of nanoparticles for early diagnosis and targeted drug therapy of various diseases. In fact, the small size, customized surface, upgraded solubility, or multi-functionality of nanoparticles enabled them to interact with complex cellular functions in new ways which opened many doors and created new biomedical applications. These studies demonstrated that nanotechnology vehicles can formulate biological products effectively, and this nano-formulated products with a potent ability against different diseases, were represented to have better biocompatibility, bioaccessibility and efficacy, under in vitro and in vivo conditions.
Abstract: The various carbon nanostructures e.g. single-walled carbon nanotubes (SWCNTs) web, graphene nanosheets and metal nanoparticle decorated graphene sheets have been synthesized in large quantity by electrical arc discharge method under an argon atmosphere. The as-synthesized nanostructures were characterized by different characterization techniques such as XRD, SEM, TEM, Energy dispersive X-ray spectroscopy, Raman and FTIR spectroscopy. The SWCNT webs of length ~6 cm abundantly containing aligned SWCNTs have diameter of about 1.8 nm and form buckybook like structure. Few layer graphene (FLG) sheets were prepared by electric arc discharge of high purity graphite electrodes in a varying argon gas atmosphere (250-500T). The largest areal extent of graphene (with lowest number of layer i.e. four) has been found at 350T argon pressure. A one step method is also reported for the decoration of these graphene nanosheets with iron and nickel nanoparticles through arc discharge method.
Abstract: In this work, Nono-crystalline aluminum carbide particles were synthesized using both mechanical and thermal treatments. Frist, Al and graphite powders had been milled in a planetary ball mill. Then, milled mixtures have been annealed isothermally after the mechanical activation. The effects of two processes on the synthesized products were separately studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and simultaneous thermal analysis (STA) methods. Further, the grain size, lattice strain and dislocation density values were calculated according to XRD data. The results showed that mechanical alloying process can create an ultra-fine microstructure. The grain size was mostly reduced after 40 h milling as well as the heat treatment at 550 °c and 2 h. in fact, the high rate of plastic deformation of aluminum particle during milling process lead to rising the internal energy of particles, and finally, nanocrystals of Al4C3 formed with the size of 14 nm. However, thermal analysis indicated that the mechanical activation of aluminum and the presence of carbon can play key roles in synthesis of aluminum carbide. Key words: Mechanical alloying, annealing, Al and graphite powders, Solid state reaction, Nono-crystalline aluminum carbide.
Abstract: An efficient, economic and easy method for removing 99% of catalyst particle from high pressure carbon monoxide (HiPCO) single walled carbon nanotubes (SWCNT) is reported. The experiment is carried out at low temperature followed by acid treatment. The process exploited here is oxidation of the carbon impurities to gaseous phase as CO2 and removal of oxidized catalyst debris using acid treatment. Stability of SWCNT at these temperatures does not allow any damage to the nanotubes, however, some damage is observed which can be attributed to the oxidation of catalyst particles and their removal. The purified sample showed very less/no amount of amorphous carbon and catalyst impurities. Characterization of the material was carried out using Raman spectroscopy, Thermogravimetric analysis (TGA), Scanning electron microscopy (SEM), Transmission electron microscope (TEM) and Energy Dispersive Spectroscopy (EDAX). The resultant SWCNT were found to be highly pure. EDAX spectroscopy showed that the purified sample had only 0.5wt% of catalyst impurities whereas the as prepared once have 9.09wt%, also, TGA curve of the treated sample showed a very significant increase in the oxidation temperature indicating less defect and less catalyst content in the sample. The non- carbonaceous residue after purification is about 0.3%. highly efficient purification of SWCNT using the proposed method. This work provides a basis on removing the catalyst particles completely.
Abstract: In this work, a novel and facile sequential cation-exchanging strategy was developed to synthesize phosphorus doped g-C3N4 nanotubes, and resulted nanotubes were composed of small nanorods with length of several hundred nanometers by oriented aggregation. As obtained products exhibit greatly enhanced photocatalytic hydrogen evolution with rate of 4.59 mmol h-1 g-1, which is 16 times higher than that of the bulk g-C3N4 under visible light irradiation. Mechanism investigation reveals that the superior photocatalytic property could be attributed to its improved visible light absorbance, well suppressed charges recombination and nanostructural construction.