In the present study, Ag-doped nickel oxide nanoparticles (NiO-NPs) were synthesized through a sol–gel method using of
Cydonia oblonga
plant extract as a new green stabilizing agent and employed ...Ni(NO
3
)
2
·6H
2
O and AgNO
3
as nickel and silver sources, respectively. The synthesized Ag-doped NiO-NPs have been calcinated at 400 °C. Formation of Ag-doped NiO-NPs was confirmed by the means of XRD, FESEM/EDAX, FTIR, TGA/DTG, UV–Vis spectrophotometry, and VSM techniques, and effect of silver diluent doping on the photocatalytic properties of NiO-NPs was investigated. The XRD results have indicated that the size of Ag-doped NiO-NPs has increased as the Ag concentration had been raised. The obtained particle size in optimized conditions (Ag-doped 3%) has been reported to be about 9.24 nm. In the following, the photocatalytic activity of Ag-doped NiO-NPs has investigated the degradation of Rhodamine B (RhB) dye, and according to the obtained results, about 75% of RhB degraded under UV-light after 200 min. The cytotoxicity effect of Ag-doped NiO-NPs on PC12 cell lines has been investigated by MTT assay, and the results showed that Ag-doped NiO-NPs inhibited cancer cells (IC
50
̴ 35 µg/ml).
Graphic abstract
Catalytic materials are available in several forms and their preparation includes various protocols with many possible preparation schemes. Also, the preparation of any catalyst includes several ...complex processing sequences, many of which are not fully well known. Therefore, minor changes in preparative details can cause noticeable changes in the properties of the final catalyst. Our aim in this study is to provide the causes and effects relations of the preparation processes by using a fuzzy decision-making trial and evaluation laboratory (DEMATEL) method. The DEMATEL method is used to identify and analyze the problems encountered while preparing the catalyst according to the effect relationship diagram. In addition, fuzzy sets go through uncertainty in decision making and comments from DEMATEL experts. When the results are analyzed it can be seen that homogeneous coating and determining proper calcination temperature is crucial in terms of causes. Besides, it has been found that it is very important to choose correct molar densities, and make the physical properties of the material to be coated suitable in accordance with humidity and temperature. Findings from the study will contribute to proper catalyst preparation and coating.
Highlights
The most frequently encountered problems during catalyst synthesizing with sol–gel method were compiled and analyzed.
The problems of catalyst preparation were investigated with the fuzzy DEMATEL algorithm.
Preventive and corrective solutions have been proposed in order to synthesize catalysts with minimal deficiency.
•TEOS and BTESE films were improved by coating sols on plasma-treated Me-SiO2 films.•BTESO sols were well coated on Me-SiO2 films with and without plasma treatment.•The gas performance of ...BTESE/Me-SiO2 membrane was improved with plasma treatment.
Uniform and defect-free silica films were prepared by spin-coating silica sols on plasma-treated hydrophobic sub-layers. Three kinds of silica films were prepared using tetraethoxysilane (TEOS), bis(triethoxysilyl)ethane (BTESE) and bis(triethoxysily)octane (BTESO) via sol–gel method. First, hydrophobic sub-layers were pre-coated on silicon wafers with Me-SiO2 sols prepared from mixtures of methyltrimethoxysilane (MTMS) and TEOS. After firing at 400°C, the films showed water contact angles of 120°. Then TEOS- and BTESE-derived sols were directly spin-coated on the Me-SiO2 films, resulting in separated and scattered coatings. A H2O/N2 plasma modification method was used to change the properties of the Me-SiO2 films from hydrophobicity to hydrophilicity without damaging either the surface morphology or the bulk chemistry. After the treatment, the TEOS- and BTESE-derived sols formed homogenous films. On the other hand, the Me-SiO2 films were fully coated with BTESO either with or without plasma treatment. This was probably due to both the polar (–OH) and non-polar (long –CH2) portions of the BTESO-derived sols. For gas separation applications, the corresponding BTESE membranes showed great improvement in gas selectivity after the plasma treatment of hydrophobic Me-SiO2 layers.
In this study, several TiO
2
mesoporous nanoparticles with different mol% of niobium and silver were synthesized using the sol–gel method. The crystalline phase, chemical state, photocatalytic and ...optical properties, specific surface area, and morphology of mesoporous nanoparticles were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–Vis reflective spectroscopy (UV–Vis), Brunauer–Emmett–Teller-specific surface area (BET) and field emission scanning electron microscopy (FESEM). With increasing calcination temperature, the photocatalytic activity of the samples gradually increased due to the improvement of crystallization of the anatase and rutile phases. Nb/Ag codoping sample calcined at 550 °C has reduced the band gap energy (3.17 eV to 3.06 eV) and improved the photocatalytic properties of samples under visible light (xenon lamp, 200 W for 1 h and 2 h). Doped TiO
2
mesoporous nanoparticles were shown to have the highest photocatalytic activity as compared with the pure TiO
2
nanoparticles. The best photocatalytic efficiency of codoped TiO
2
mesoporous nanoparticles was observed for the TNA3 sample calcined under 550 °C, containing molar contents of Nb (0.5 mol%) and Ag (1 mol%) dopant ions with 95.60% efficiency.
Synthesis of Nb/Ag-codoped TiO
2
(TNA) nanoparticles by sol–gel method
Highlights
Nb/Ag additive enhanced significantly photocatalytic properties of TiO
2
based nanoparticles for remove of organic compounds (MB).
Structural, optical and surface analysis of samples dependent to dopant concentration.
Nb/Ag codoped TiO
2
nanoparticles is promising for photocatalytic properties in visible light.
Pure and Mg-doped ZnO (3 at. %) nanoparticles were prepared based to sol–gel route under supercritical conditions of ethyl alcohol. The samples were characterized by certain techniques. XRD patterns ...showed the hexagonal wurtzite crystalline structure of ZnO and Mg-doped ZnO nanoparticles. The TEM image demonstrates the hexagonal shape and the nanometric size of the nanostructures. SEM images show the presence of hexagonal like shape nanoparticles and the increase of grain size for the Mg doped sample. The corresponding EDX analysis proves the existence of Mg with low concentrations and shows coherent distribution of high concentrations of Zn and O elements. The UV–Vis–NIR spectroscopy exhibits high absorbance of the prepared samples in the UV range. Thereafter, the effect of doping ZnO by Mg on sensing properties has been investigated. The obtained results outline an enhancement in sensing performances for Mg doped ZnO based sensor, which exhibits, competitive response and recovery times, high and linear response at working temperature 300 °C toward low and high ethanol concentrations with detection limit less than 1 ppm. Long term stability has been also investigated and sensor exhibits after one year, similar and reproducible responses.
Display omitted
•Pure and Mg (3 at.%) doped ZnO nanoparticles have been synthesized using sol–gel technique.•The TEM observation shows prismatic shape and nanosized particles confirming the XRD results.•3 at% Mg doped ZnO (M3ZO) based gas sensor exhibits high sensitivity and excellent response to ethanol.•M3ZO has highest Response/ppm ratio compared to literature results at 300 °C and 50%RH.•M3ZO sensor Response exhibits, good linear relationship with concentration, and excellent long term stability.
In this paper, we report the experimental results on the synthesis of water glass based silica aerogels, which were dried under ambient pressure. Water glass was hydrolyzed and condensed in water ...using HCl as the catalyst. To minimize shrinkage during drying process, N,N-dimethylformamide (DMF), acting as drying control chemical additive (DCCA), was introduced. Before the ambient pressure drying, solvent exchange and surface modification were completed. In order to get hydrophobic aerogel, trimethylchlorosilane (TMCS) was used to modify the hydrophilic hydrogel surface. Here a large amount of TMCS can be saved compared with that in single step solvent exchange/surface modification method. The effects of DMF on the physical and textural properties of the resulting aerogels were investigated. When the molar ratio of Si in water glass to DMF is 2.23, the synthesized silica aerogels have better properties. Characterized by FT-IR, SEM, BET, etc., the resulting aerogels have well-developed mesoporous structure (mean pore size of ~15nm) with super hydrophobicity (contact angle of 161°) and excellent absorption capacity of organic liquids.
•Min. amount of TMCS was obtained through experiments for complete surface modification.•Optimum volume ratio of H2O to water glass was gotten.•Proper amount of DMF can uniform the PSD of as-prepared silica aerogels.•More than 0.9ml organics (some) can be absorbed by 1cm3 of the silica aerogels.
This study focuses on the synthesis and characterization of Zirconium(IV) Propoxide (ZTP), Colloidal Silica (CS), and Methyltrimethoxysilane (MTMS)-derived non-stick hard coatings prepared via the ...sol–gel method. In the synthetic procedure, two different solutions were prepared separately based on the different hydrolysis rates of the silicon (SolS) and zirconium (SolZ) components. Polydimethoxysilane (PDMS) and Fluoralkylsilane (FAS) were used as hydrophobicity-promoting agents. The solution was applied onto aluminum surface, which was afterward dried and densified at 250 °C. The final solution was characterized by FTIR spectroscopy to determine the Zr–O–Si hetero-bonding and Si–O–Si and Zr–O–Zr homo-bonding. Coatings were analyzed by their hardness, hydrophobicity, and gloss. A homogeneous solution and crack-free hybrid coating was obtained. FTIR results showed that homo- and hetero-bonding between Zr and Si elements were obtained from a precipitation-free solution. Measured contact angles varied between 100° and 112°, and these results were evaluated according to the surface and gel structure.
Highlights
A crack-free, hydrophobic, hard hybrid thin films were synthesized using ZTP, MTMS and CS via sol–gel method.
ZTP increased the contact angle of the film surface.
Precipitation-free SolS solution was obtained due to the reactions between methyl groups in MTMS and the colloidal silica particles.
PDMS and FAS components further increased the wetting angle of the hybrid film up to a specific ratio.
FTIR results showed that Zr–O–Si hetero-bonding and Si–O–Si, Zr–O-Zr homo-bonding were obtained as result of the precipitation-free solution.
Excellent biocompatibility and its similar biological characteristics to bone apatite, extensively expand the hydroxyapatite (HA) usage in bioimplant applications. The crystallite size of HA is one ...of the most administrated parameter for determination of reaction rate at the interface of artificial/natural bones. This study tried to propose a new predictive model by employment of the gene expression programming (GEP), i.e., a powerful soft computing technique, to estimate the crystallite size of HA that were prepared by sol–gel route. Firstly, 37 different reliable experiments were carried out considering the type of phosphor precursor, pH, drying temperature, aging time, temperature and time of calcination as practical parameters as input variables, and HA crystallite size as output variable. Absolute fraction of variance (
R
2
), mean absolute percentage error (MAPE), root relative squared error (RRSE), and mean squared error (MSE) were considered to validate the most appropriate GEP model/s. The experiment results were divided randomly into 29 training sets and 8 testing sets. Finally, the best model was selected in
R
2
= 0.9929, MAPE = 2.8, RRSE = 0.0956, and MSE = 1.7. The results of simulation confirmed the unique features of GEP for the determination of HA crystallite size prepared by sol–gel route.
Predicted vs. experimental HA crystallite size through GEP-3, GEP-8 and GEP-6 models in (
a
) training phase, and (
b
) testing phase.
In this paper, we introduce the synthesis of undoped ZnO and 5 wt % Gd/K co‐doped ZnO compounds to improve photocatalytic activity. Undoped ZnO particles and Gd/K co‐doped ZnO particles were ...synthesized by the sol‐gel method. The samples were studied by X‐ Ray Diffraction (XRD), Scanning Electron Microscopy (SEM)/energy dispersive X‐ray (EDX), Ultraviolet Visible Spectroscopy (UV‐Vis), Brunauer–Emmett–Teller (BET), and particle size analysis. Then tehir photocatalytic activities were tested. SEM micrographs showed that the particle size was in the sub‐micrometer or nanometer range. Particle size analysis revealed that the mean size was closer to the micrometer range. The specific surface area of the powder was obtained quite low in accordance with the larger particle size. The photocatalytic activity of 5% Gd/K co‐doped ZnO was compared with undoped ZnO in the degradation methyl blue. When their photocatalytic activities were examined, Gd/K co‐doped ZnO showed ∼66% degradation at 60 min, while undoped ZnO showed ∼52% degradation at the same time.
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