Co-precipitation Method In Presence Research Articles

Effects of metal promotion on the performance, catalytic activity, selectivity and deactivation rates of Cu/ZnO/Al2O3 catalysts for methanol synthesis

Methanol synthesis catalysts of Cu/ZnO/Al2O3 were prepared using co-precipitation method in presence of Cr and Mg promoters. Precursors were characterized by Air-TGA and XRD. After calcination at 350 °C, catalysts were analyzed by BET and XRD. H2-TGA and H2-TPR were used to determine reduction properties of the catalysts. Co-addition of Cr and Mg resulted in the formation of larger surface area and smaller CuO particles by enhancing dispersion of CuO in the catalyst composition. Catalytic activity, selectivity and deactivation rates of synthesized catalysts were tested at 270 °C and 3 MPa for 144 h. Mg or Cr addition to the catalyst formulation reduced the methanol productivity whereas the co-addition of Cr and Mg increased the methanol productivity. At 144 h reaction time, catalysts with Mg:Cr molar ratios of 2:1 and 1:1 had the highest methanol selectivities and methanol weight time yields of 97.7 and 98.3%, and 0.53 and 0.52 gtotal methanol production gcatalyst−1 h−1, respectively. The catalysts without Cr promoter deactivated rapidly. The presence of Cr in the catalyst composition reduced deactivation rates and sintering of the catalysts. Deactivation rates of Mg and Cr co-promoted catalysts followed a cyclic trend and possible regenerative characteristics.

Synthesis of MnMoO4 Nanorods by a Simple Co-Precipitation Method in Presence of Polyethylene Glycol for Pseudocapacitor Application

Synthesis of MnMoO4 Nanorods by a Simple Co-Precipitation Method in Presence of Polyethylene Glycol for Pseudocapacitor Application

A study on influence of superparamagnetic iron oxide nanoparticles (SPIONs) on green gram (Vigna radiata L.) and earthworm (Eudrilus eugeniae L.)

Nanoparticles usage are now emerging as hazardous nanopollutants due to inappropriate usage and improper disposal. Superparamagnetic Iron Oxide Nanoparticles (SPIONs) is a widely used nanoparticle with various applications. In this study, SPIONs was evaluated for its impact against Vigna radiata and Eudrilus eugeniae. SPIONs were synthesized by chemical co-precipitation method in presence of cobalt chloride. The produced SPIONs was characterized using UV-Visible Spectroscopy, SEM (Scanning electron microscopy), EDX (Energy dispersive X-ray spectroscopy), XRD (X-ray diffraction), TEM (Transmission electron microscopy), AFM (Atomic force microscopy), XPS (X-ray photoelectron spectroscopy) and Zeta potential. The synthesized SPIONs were crystalline and monodispersed with size ranging between 15 nm and 20 nm. The seedlings of SPIONs treated Vigna radiata were found to have reduced root and shoot growth. The bioaccumulation of iron oxide in the treated plants was confirmed by ICP-OES (Inductively coupled plasma - optical emission spectrometry) analysis and Prussian blue staining. Cellular destruction and reduced reproduction rate were found in SPIONs exposed Eudrilus eugeniae and ICP-OES analysis of earthworm samples affirmed the bioaccumulation of SPIONs.

Structural and photocatalytic degradation studies of rice straw based MgO nanocomposite

The present study is focused on the comparison of structural and photocatalytic degradation activities of nanocomposite of MgO formed with rice straw, a biopolymer. For comparison, counter parts were also synthesized. Nanoparticles of magnesium oxide were synthesized through controlled co-precipitation method in presence of citric acid. Structural characterizations of all the synthesized samples were carried out using XRD. Comparison of XRD of metal oxide with JCPDS confirmed that the formed metal oxide was MgO. Photocatalytic degradation of organic dyes Congo Red, an acidic dye and Methylene Blue, a basic dye was done.

Structural, Optical and Photocatalytic Degradation Studies of Polymer Based Fe2o3 Nanocomposite

The present study is focused on the comparison of structural and optical properties of nanocomposite of Fe2O3 formed with both rice straw, a biopolymer and polyindole, a conducting polymer. For comparison, counter parts were also synthesized. Nanoparticles of iron oxide were synthesized through controlled co-precipitation method in presence of citric acid. Structural characterizations of all the synthesized samples were carried out using XRD. Comparison of XRD of metal oxide with JCPDS confirmed that the formed metal oxide was Fe2O3. Optical studies of all the samples were carried out using UV/Vis spectroscopy. From band gap calculation it was seen that all of them except polyindole showed subgaps. Also these samples were employed as photocatalyst in the photocatalytic degration study of organic acidic dye Congo Red. Results suggested that the nanocomposites prepared in the present study are promising photocatalysts. Also an increase in degradation efficiency was observed in the case of nanocomposites when compared to their counterparts.

BiOCl-Ag8SnS6 heterostructure: Facile preparation and photocatalytic applications

BiOCl-Ag8SnS6 heterostructured nanocomposites have been synthesized by chemical coprecipitation method in presence of ethylene glycol solvent and capping agent at a moderate temperature (100 °C, 4 h). The BiOCl-Ag8SnS6 heterostructures were characterized by X-ray diffraction, transmission electron microscopy, UV–vis NIR spectroscopy and Brunauer–Emmett–Teller (BET) surface area measurement. XRD pattern of BiOCl-Ag8SnS6 heterostructure showed the peaks corresponding to orthorhombic structure of Ag8SnS6 nanoparticles and tetragonal structure of BiOCl indicating that they exist in biphasic form. BET surface area of BiOCl microspheres, Ag8SnS6 nanoparticles and BiOCl-Ag8SnS6-2 were found to be 1.91 m2/g, 2.35 m2/g and 4.52 m2/g, respectively. BiOCl-Ag8SnS6 heterostructured composites exhibited robust photocatalytic degradation towards degradation of congo red dye than that of single phase BiOCl and Ag8SnS6 nanoparticles under sunlight irradiation. This could be ascribed to heterostructure effect between BiOCl and Ag8SnS6 nanoparticles which facilitate the separation and easy transfer of photogenerated electrons and holes, across the BiOCl-Ag8SnS6 interface resulting into an enhanced photocatalytic activity. The results of different scavengers confirm that photogenerated holes and superoxide radicals was the main active species for oxidising congo red dye during the photocatalytic process.

普朗尼克F127调控下MnFe<sub>2</sub>O<sub>4</sub>纳米粒子的共沉淀制备及其性能表征

MnFe2O4纳米粒子在核磁共振成像和肿瘤磁热疗的应用上具有很大潜力。但是其应用于生物医学领域的主要障碍是难以制备形貌均一、分散性好、磁性能优异且生物相容性良好的MnFe2O4纳米粒子。目的：通过F127调控下的共沉淀法制备粒径均匀且磁性能较好的MnFe2O4纳米粒子，且通过普朗尼克F127的修饰提高其分散性并降低MnFe2O4纳米粒子的细胞毒性。方法：以F127为模版，采用共沉淀法制备MnFe2O4磁性纳米粒。利用X射线衍射(XRD)、透射电子显微镜(TEM)、振动样品磁强计(VSM)、傅立叶变换红外光谱(FT-IR)等对样品的成分、微观结构、形貌和粒径以及磁性能进行表征。通过MTT实验对样品的细胞毒性进行评价。结果：采用普朗尼克F127调控下的共沉淀法成功制备大约50 nm的球形MnFe2O4铁磁性纳米粒子，其比饱和磁化强度为44.8 emu/g，对HUVEC细胞无明显毒性。结论：共沉淀过程中，F127能够控制MnFe2O4纳米粒子的形貌、粒径，从而提高其磁性能，另外还可以降低其细胞毒性。该方法在生物医学应用上具有很大的潜力。 MnFe2O4 nanoparticles have great potentials in Magnetic Resonance Imaging and tumor hyper-thermia. However for biomedical applications, the main challenges would be of great difficulty to synthesize MnFe2O4 nanoparticles with homogeneous size and morphology, high magnetization, and good biocompatibility. Pluronic F127 was utilized to regulate the coprecipitation process of MnFe2O4 nanoparticles. Objective: The regulation of Pluronic F127 in the coprecipitation process was expected to facilitate the formation of MnFe2O4 nanoparticles with uniform size and morphology, higher magnetization, and low cytotoxicity. Methods: MnFe2O4 nanoparticles were prepared by chemical coprecipitation method in presence of Pluronic F127. X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM) were used to characterize the composition, microstructure, morphology, and magnetization of the prepared MnFe2O4 nanoparticles. And MTT assays were conducted to investigate their cytotoxicity. Results: The ferromagnetic MnFe2O4 nanoparticles (F127-NPs) were successfully synthesized in the presence of Pluronic F127 via coprecipitation method. Compared to the nanoparticles prepared without Pluronic F127, F127-NPs exhibited a more uniform size of ca. 50 nm and a sphere-like shape. Moreover, F127-NPs possessed a higher magnetization (44.8 emu/g) and exhibited little inhibition to HUVE cells. Conclusion: Pluronic F127 could regulate the coprecipitation process to form the high quality MnFe2O4 nanoparticles and improve the cytocompatibility of nanoparticles. And this method is of a great potential to be applied in the field of biomedicine.

Effect of synthesis conditions on the preparation of MgSnO 3 powder via co-precipitation method

Nanocrystalline MgSnO 3 powders have been synthesized using co-precipitation method in presence of sodium bis(2-ethylhexylsulfosuccinate), Aerosol OT (AOT) as anionic surfactant. Statistical Box–Behnken experimental design was used to investigate the effect of main parameters (i.e. surfactant concentration, calcination time and calcination temperature) on MgSnO 3 powders formation, crystallite size, particle size mean diameter and morphology. MgSnO 3 particles were investigated using XRD, SEM, and laser diffraction particle size analysis (Coulter LS 13 320). XRD patterns revealed that the magnesium meta-stannate MgSnO 3 was single phase at 800 °C and the peaks intensities were changed by increasing the calcination temperature from 1000 to 1200 °C due to the decomposition of meta-magnesium stannate MgSnO 3 to ortho-magnesium stannate Mg 2SnO 4 and stannic oxide SnO 2. SEM micrographs showed that the morphologies of the powders formed were changed by increasing the calcination temperature from 800 to 1200 °C from foam-like structure to rectangular-plate shape. Coulter LS 13 320 showed that the average particle size diameter was about 4.43 μm. The results indicated that the calcination time, calcination temperature and surfactant addition were significant on the produced magnesium stannate mean diameter.