Chemical Mixing Method Research Articles

Polyoxovanadate derived VN@C composite catalysts by different synthesis routes as Pt-free counter electrode for dye-sensitized solar cells

Vanadium-based nitrides have been applied as Pt-free counter electrodes (CEs) electro-catalysts for dye-sensitized solar cells (DSSCs) due to inexpensive cost and easy doping and modification. Herein, polyoxovanadate (NH4)2V6O16 assisted by melamine to prepare VN@C composites by five different synthesis routes, including solvothermal, sol–gel, hydrothermal, ball milling, and chemical mixing method. And then, five VN@C composites were assembled as CEs in the encapsulated DSSCs, and yielded power conversion efficiencies of 4.47, 5.04, 5.35, 5.49 and 6.11% for regenerate traditional I3−/I− shuttles by the photocurrent-photovoltage (J-V) test, respectively. The catalytic performances of VN@C composites CEs were assessed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Tafel polarization experiments, and the significant effects of different synthetic routes were confirmed. The results revealed that VN@C composite CEs prepared by chemical mixing method had higher catalytic performance in DSSCs, which is due to the improvement of conductivity and the high concentration of active sites.

A Comparative Study of Cytotoxicity of PPG and PEG Surface-Modified 2-D Ti3C2 MXene Flakes on Human Cancer Cells and Their Photothermal Response.

The MXenes are a novel family of 2-D materials with promising biomedical activity, however, their anticancer potential is still largely unexplored. In this study, a comparative cytotoxicity investigation of Ti3C2 MXenes with polypropylene glycol (PPG), and polyethylene glycol (PEG) surface-modified 2-D Ti3C2 MXene flakes has been conducted towards normal and cancerous human cell lines. The wet chemical etching method was used to synthesize MXene followed by a simple chemical mixing method for surface modification of Ti3C2 MXene with PPG and PEG molecules. SEM and XRD analyses were performed to examine surface morphology and elemental composition, respectively. FTIR and UV-vis spectroscopy were used to confirm surface modification and light absorption, respectively. The cell lines used to study the cytotoxicity of MXene and surface-modified MXenes in this study were normal (HaCaT and MCF-10A) and cancerous (MCF-7 and A375) cells. These cell lines were also used as controls (without exposure to study material and irradiation) to measure their baseline cell viability under the same lab environment. The surface-modified MXenes exhibited a sharp reduction in cell viability towards both normal (HaCaT and MCF-10A) and cancerous (MCF-7 and A375) cells but cytotoxicity was more pronounced towards cancerous cell lines. This may be due to the difference in cell metabolism and the occurrence of high pre-existing levels of reactive oxygen species (ROS) within cancerous cells. The highest toxicity towards both normal and cancerous cell lines was observed with PEGylated MXenes followed by PPGylated and bare MXenes. The normal cell’s viability was barely above 70% threshold with 250 mg/L PEGylated MXene concentration whereas PPGylated and bare MXene were less toxic towards normal cells, even at 500 mg/L concentration. Moreover, the toxicity was found to be directly related to the type of cell lines. In general, the HaCaT cell line exhibited the lowest toxicity while toxicity was highest in the case of the A375 cell line. The photothermal studies revealed high photo response for PEGylated MXene followed by PPGylated and bare MXenes. However, the PPGylated MXene’s lower cytotoxicity towards normal cells while comparable toxicity towards malignant cells as compared to PEGylated MXenes makes the former a relatively safe and effective anticancer agent.

Antibacterial activity and physical features of some nano metals and their oxides

In this paper, nanomaterials and their oxides have been prepared using a simple chemical mixing method for use as antibacterial agents (Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae). The synthesized nanoparticles were characterized using different techniques like FESEM, optical properties and XRD. The results of the composition showed that the nanomaterials had diameters ranging from (50-70) nm.

Enhancement of Long-Persistent Phosphorescence by Solid-State Reaction and Mixing of Spectrally Different Phosphors.

Rare-earth-doped oxide-based phosphors have attracted great interest as light-emitting materials for technical applications and fundamental research because of their high brightness, tunable emission wavelength, and low toxicity, as well as chemical and thermal stability. The recent development of rare-earth-doped nanostructured materials showed improved phosphorescence characteristics, including afterglow and lifetime. However, the development of highly efficient phosphors remains challenging in terms of brightness and long persistence. Herein, novel protocols were developed for improving phosphorescence characteristics based on the energy transfer effect by chemical mixing of spectrally different phosphors. This protocol is based on the simple mixing method of different phosphors, which is totally different from the conventional methods but provides much brighter persistent phosphorescence. Simple chemical mixing methods significantly improved the afterglow intensity and lifetime of green and blue phosphors regardless of mixed time when subjected to a high-temperature solid-state reaction. In particular, chemical mixing after a high-temperature solid-state reaction enhanced the phosphorescence intensity more effectively than did chemical mixing before the reaction. We achieved increased luminescence of the phosphor, which is 10 times greater than that of the control sample, from all of the chemical mixing methods, which resulted in more efficient energy transfer than previously reported studies. Chemical mixing of three spectrally different phosphors was also performed to achieve multistep energy transfer for the first time, exhibiting a much higher afterglow intensity (∼2 times) than that of single-step energy transfer. This study provides a novel and simple method for the production of bright and long-persistent phosphors and thus expands their application range.

Role of molybdenum trioxide in enhancing the humidity sensing performance of magnesium ferrite/molybdenum trioxide composite

In the present work, we prepared magnesium ferrite/molybdenum trioxide (MFMO) nanocomposite using mechano chemical mixing method for humidity sensor at room temperature. Enhancement in active sites for water adsorption in the composite due to the presence of MoO3 confirmed from X-ray diffraction (XRD) studies. Change in grain size distribution and increase in intergranular pores in the composite favouring water adsorption confirmed from its scanning electron microscopy (SEM) image. Increased agglomeration of nano sized particles and improved crystallinity of the composite confirmed from Transmission electron microscopy (TEM) studies and selected area electron diffraction (SAED) pattern. The composite showed maximum sensing response of 4902 as against 183 of MF in the range 11%–97% RH. The response and recovery times of the composite were found to be 45 s and 74 s respectively while those of MF 225 s and 364 s respectively. The nanocomposite sample showed stable humidity sensing ability and a low humidity hysteresis. Molybdenum trioxide plays a major role in enhancing the humidity sensing performance of MFMO composite at room temperature. The sensing mechanism discussed on the basis of chemisorptions, physisorption and capillary condensation processes.

Impact of vanadium‐, sulfur‐, and dysprosium‐doped zinc oxide nanoparticles on various properties of PVDF/functionalized‐PMMA blend nanocomposites: Structural, optical, and morphological studies

ABSTRACTThe polymeric blend was fabricated with crystalline poly(vinylidene fluoride) (PVDF)/amorphous functionalized‐poly(methyl methacrylate) (PMMA) in 70/30 w/w ratio by chemical mixing method. Functionalization of PMMA was achieved with 2‐amino‐5‐nitrobenzoic acid. The prepared polymer blend was used as a matrix to synthesize nanocomposites with undoped/doped zinc oxide (ZnO) nanoparticles. Doping in ZnO was achieved with vanadium, sulfur, and dysprosium elements as a dopant. The structural, optical, electronic, and morphological properties of undoped/doped nanosized ZnO and blended nanocomposites were accessed through sophisticated analytical techniques, that is, Fourier transform infrared (FTIR), ultraviolet–visible (UV–vis), UV–vis–diffuse reflectance spectra, nuclear magnetic resonance, fluorescence spectroscopy, X‐ray diffraction (XRD), transmission electron microscopy, and scanning electron microscopy. The FTIR band at 1165–1176 cm−1in functionalized‐PMMA indicate the formation of aliphatic C‐N bond along with aromatic1H chemical shift (δ) at 7.134, 7.829 and 8.210 ppm confirm the successfully functionalization of PMMA. The prominent XRD peak at 2θ = 20.8° in nanocomposites shown improvement in β‐phase of PVDF. The results show that Dy doped ZnO nanoparticles create remarkable effect on various properties of nanocomposites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2019,136, 47116.

"Effect of Substitution of Positive Ion (M+2) on the Physical Properties of M-Fe2O4 "

"Cobalt, Manganese and Magnesium ferrites powders have been synthesized using chemical mixing method. Calcination and sintering temperatures were 800oC respectively. The characteristics of spinal ferrite have been investigated by XRD technique while the magnetic characterization samples have been done using vibrating sample magnetometer (V.S.M). The magnetic properties such as initial magnetic permeability, quality factor, inductor factor and power loss density are studied under variation of frequency using L.C.R meter as well. Saturation magnetization, coercive field and remanent agnetization are determined from hysteresis loops for all prepared sample.

Adsorption and photocatalysis of 2-ethyl-1-hexanol over graphene oxide–TiO2 hybrids post-treated under various thermal conditions

High temperature (>300°C) post-treatment of two-dimensional graphene oxide-coupled titania (GO–TiO2) hybrids may enhance their photocatalytic performances. This concept has not yet been fully assessed. In the present study, we explored the applicability of GO–TiO2 hybrids synthesized using a chemical mixing method, followed by post-treatment under various thermal conditions (200–500°C), for the degradation of low-concentration gas-phase 2-ethyl-1-hexanol (2E1H) in continuous-flow mode under visible-light illumination. The morphological and optical characteristics of the synthesized photocatalysts were investigated by field-emission transmission electron microscopy, thermal gravimetric analysis, X-ray diffraction technique, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, and N2 adsorption–desorption analysis. The GO–TiO2 hybrid post-treated at 400°C exhibited longer breakthrough and saturation times and a higher capacity for 2E1H adsorption than did GO–TiO2 post-treated at 200°C. The photocatalytic 2E1H degradation efficiencies of the post-treated GO–TiO2 hybrids were superior to those of the untreated GO–TiO2 hybrid and neat TiO2 samples. Moreover, the photocatalytic activities of the GOkTiO2 hybrids increased as the post-treatment temperature increased from 200 to 400°C, and decreased as the temperature was further increased to 500°C, indicating that the treatment temperature can be increased up to at least 400°C without significant reduction of the photocatalytic performance. The photocatalytic activity of the GO–TiO2 hybrid post-treated at 400°C depended strongly on three process parameters: relative humidity, initial contaminant concentration, and catalyst mass. There was no appreciable loss of photocatalytic efficiency for the GO–TiO2 hybrid post-treated at 400°C after five cycles. The average 2E1H mineralization efficiency was 55.1%, while the average photocatalytic efficiency was 99.3%. Two gaseous organic compounds, i.e., 3-heptanone and 2-ethyl hexanal, and carbon monoxide were identified as the primary partially oxidized intermediates. The average carbon monoxide concentration (0.49ppm) was well below the permissible 8-h exposure level (25ppm).

Preparation of Ultrafine Barium Titanate under Wet Chemical Mixing Method with TiOSO4. Sintering Performance and Dielectric Properties

Preparation of Ultrafine Barium Titanate under Wet Chemical Mixing Method with TiOSO4. Sintering Performance and Dielectric Properties

Synthesis and Optical Properties of Anatase-TiO2Nanoparticles in Commercial Poly(methylmethacrylate): A Green Approach for Wider Acceptability?

ABSTRACT The present paper reports synthesis and optical properties of nano-sized anatase-TiO2 particles/poly(methylmethacrylate) (PMMA) nanocomposite. Because as-prepared TiO2 nanoparticles are well dispersed in solvents such as DMF and toluene, they can be easily loaded homogeneously by chemical mixing method in commercial PMMA. No costly apparatus was used for such composite fabrication and the method can be considered quite green and human friendly and it can be best described as beaker nanotechnology. Small solvent dependency of the nanoTiO2 in PMMA was noticed, which showed only slight differences in their band gap energy as against the original TiO2 nanoparticles. The absorption wavelength of as-prepared TiO2 shifted from 300 to about 300–320 nm when toluene or DMF was used as a dispersion medium, indicating a red-shift of about 10–20 nm, mainly due to increasing concentration of the nanoparticles. Photoluminescence measurement showed near band gap emission from the so-obtained nanocomposite. The t...

Preparation of niobates of rhodium and nickel and their catalytic behaviors during calcination and reduction treatments

Double oxides of Rh and Ni have been prepared by chemical mixing methods. Silica-supported and unsupported RhNbO 4 and NiNb 2O 6 catalysts exhibited strong metal-oxide interaction behaviors in ethane hydrogenolysis activities after the decomposition of the double oxides by H 2 reduction at 500°C. Silica-supported and zeolite-supported RhVO 4 catalysts showed high activity and selectivity for dehydrogenation of cyclohexane after the decomposition in H 2. The double-oxide catalyst systems can be used as starting materials to obtain high-performance metal catalysts (redispersion of metals by H 2 reduction and regeneration of catalysts by calcination at a high temperature).

ChemInform Abstract: Preparation of Niobates of Rhodium and Nickel by Chemical Mixing Methods.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Nickel-niobia interaction induced by the reduction of NiNb2O6 supported on SiO2

Nickel niobate (NiNb2O6) supported on SiO2 was prepared by a chemical mixing method using mixed Ni and Nb citrate solutions. X-ray diffraction study showed that the NiNb2O6 compound was reduced to Ni metal and NbO2 after H2 treatment at 600 ° C, and a strong Ni-niobia interaction was induced after the decomposition of the compound: the ethane hydrogenolysis activity was suppressed severely after high temperature reduction at 600 ° C, and recovered by O2 treatment at 500 ° C followed by low-temperature reduction at 200 ° C. The selectivity of cyclohexane dehydrogenation was improved significantly by the Ni-niobia interaction, if compared with unpromoted Ni/SiO2 catalyst, and the structural change and catalytic behaviors were compared with those of Rh double oxides such as RhNbO4.

Preparation of Niobates of Rhodium and Nickel by Chemical Mixing Methods

Abstract Niobates of rhodium or nickel by were prepared by double decomposition of aqueous rhodium or nickel salt solution with tetraalkylammonium polyniobate and with alkali orthoniobate or metaniobate, as well as by decomposition of mixed citrates of niobium with Rh or Ni. The niobates thus prepared were shown by X-ray diffraction to be well-crystallized and essentially monophasic. The calcination temperature required to achieve crystallization of all the samples is much lower than ceramic methods.

Preparation of rhodium niobate compound by chemical mixing methods: Effect of preparation method on SMSI behavior of RhNbO4/SiO2 catalysts

Rhodium niobate was prepared as a complex oxide supported on silica via tetra-alkyl ammonium and citrate complexation. After calcination at 750 °C, the complex oxide was formed essentially in the monophasic columbite structure as determined by means of XRD. The two silica-supported RhNbO4 catalysts were tested for their activity toward ethane hydrogenolysis, and a large difference in SMSI behavior was observed for the two preparations.

Deep chemical mixing method using cement as hardening agent : Suzuki, Y Proc Symposium on Recent Developments in Ground Improvement Techniques, Bangkok, 29 Nov–3 Dec 1982P299–340. Publ Rotterdam: A. A. Balkema, 1985

Deep chemical mixing method using cement as hardening agent : Suzuki, Y Proc Symposium on Recent Developments in Ground Improvement Techniques, Bangkok, 29 Nov–3 Dec 1982P299–340. Publ Rotterdam: A. A. Balkema, 1985