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Nanomaterials or nanoparticles (NPs) are nano-size particles with a (1-100) nm dimension, they show unique properties such as magnetic, electronic, optical, and activating effects. That is why NPs have many applications. Titanium dioxide (TiO2) or Titania based nanoparticals are commonly used NPs due to their medical and industrial applications. TiO2 NPs are used in photodynamic therapy (SDT) and drug delivery due to their non-toxicity. In this review paper we will show some of the types, synthesis methods, and applications of nano-TiO2. [ABSTRACT FROM AUTHOR]

In this paper, we conducted a fundamental study concerning the effect of thermal treatment on the structure and morphology of 2 mol% vanadium doped ZnO nanopowders obtained by microwave assisted sol–gel method (MW). The samples were analyzed by DTA, FTIR, XRD, SEM, and UV–Vis spectroscopy. The DTA results showed that above 500 °C, there was no mass loss in the TG curves, and ZnO crystallization occurred. The XRD patterns of the thermally treated powders at 500 °C and 650 °C showed the crystallization of ZnO (zincite) belonging to the wurtzite-type structure. It was found that in the 650 °C thermally treated powder, aside from ZnO, traces of Zn3(VO4)2 existed. FTIR spectra of the annealed samples confirmed the formation of the ZnO crystalline phase and V–O bands. The micrographs revealed that the temperature influenced the morphology. The increase in the annealing temperature led to the grain growth. The SEM images of the MW powder thermally treated at 650 °C showed two types of grains: hexagonal grains and cylindrical nanorods. UV–Vis spectra showed that the absorption band also increased with the increasing temperature of thermal treatment. The MW sample annealed at 650 °C had the highest absorption in ultraviolet domain. [ABSTRACT FROM AUTHOR]

LaMnO3 and 1% Pd-, Ag-, or Y-doped perovskite type nanomaterials were prepared by the sol-gel method, followed by heat treatment at a low temperature (600 °C for 6 h). The investigation through X-ray diffraction and FT-IR spectroscopy indicated that all samples were well crystallized, without secondary phases, and that the transition metal doping changed the crystal structure from the R-3c space group for the undoped LaMnO3 to the Pm-3m space group for the doped perovskite compounds. In this research paper, the efficiencies of the perovskite LaMnO3 materials for methyl orange removal were analyzed, wherein the effect of the doping ions and of the pH on the catalytic activity were studied together with a kinetic approach for the LaMnO3 materials at different values of the pH. Moreover, in the catalytic activity, it should be noted that a slightly better performance was obtained for the Ag-doped materials compared to the Y- and Pd-doped perovskite samples. The results presented for the perovskite LaMnO3 nanomaterials reinforce the interest in these multifunctional materials to be used in industrial applications; e.g., in water treatment. [ABSTRACT FROM AUTHOR]

With its excellent ferroelectric properties such as large dielectric constant and large remanent polarization, PZT thin films are extensively used in micro-sensors and other devices. In this study, the sol–gel process was used to fabricate Pb(Zr0.52Ti0.48)O3 thin films with Pb(ZrxTi1–x)O3 seed islands. The experimental consequences demonstrate that all the Pb(Zr0.52Ti0.48)O3 thin films with Pb(ZrxTi1−x)O3 seeds show pure perovskite phase with no other impurity phases, and the electrical properties of Pb(Zr0.52Ti0.48)O3 thin films modified by Pb(ZrxTi1–x)O3 seed islands with different Zr/Ti ratios are improved, such as remanent polarization increased, dielectric properties increased, coercive electric field decreased, leakage current density decreased. In particular, the electrical properties of the Pb(Zr0.52Ti0.48)O3 thin films with Pb(ZrxTi1–x)O3 seed islands are the most optimal when the x is 0.52. This paper provides a new technique for optimizing the electrical properties of PZT thin films, which is of great significance for breaking through the bottleneck of the development of ferroelectric memory. [ABSTRACT FROM AUTHOR]

In this paper, we have investigated the structural, electrical, and dielectric properties of Ni0.1Co0.5Cu0.4Fe2-xCrxO4 (x = 0 and 0.3) ferrites. Samples have been prepared by employing the sol–gel method. The X-ray diffraction data along with Rietveld refinement were used to assess the phase purity and the structural parameters of samples. The morphology and the grain size of the prepared ferrite nanocrystals were observed with scanning electron microscopy. At room temperature, the Raman spectra displayed active phonon modes. FTIR spectra revealed two principal absorption bands due to the stretching vibration of metal oxygen in tetrahedral and octahedral sites. With increasing of Cr3+ concentration, both Raman and FTIR spectra showed that all modes shifted to higher wavenumbers. The dielectric properties were investigated using impedance complex spectroscopy in the frequency region (100‒106 Hz) at different temperatures. The ac-conductivity for both studied compounds was well analyzed using the augmented Jonscher equation. The plots of both imaginary part of permittivity (ε″) and dielectric loss (tanδ) vs. frequency, exhibit a dielectric dispersion in our compounds at low frequencies. This is described according to the Maxwell–Wagner model in agreement with Koop's theory. The modulus curve was used to interpret the relaxation behaviors of charge carriers. The Nyquist plots of impedance for both samples have been modeled using the same equivalent circuit which is formed by a three-element R-CPE connected in series. [ABSTRACT FROM AUTHOR]

Fluorogenic benzothiazole-based receptor has been easily immobilised onto filter paper and silica nanoparticle by sol-gel reaction. The sensing ability of the benzothiazole-immobilised thin layer filter paper chromatography (TLC-1) was evaluated on the basis of fluorescent changes caused by metal ions that were dropped onto the TLC plate. TheTLC-1exhibited a high affinity and selectivity for Hg2+over other competing metal ions. Therefore, theTLC-1holds promise as a portable sensor for the detection of Hg2+in aqueous solution. Furthermore, the adsorption capacity of a column packed withSiO2-1was evaluated by the application of metal ions under various experimental conditions, such as pH, flow rate and concentration. TheSiO2-1column removed 98% of Hg2+from drinking water containing 10 ppb of Hg2+. The adsorption capacity of theSiO2-1column was not strongly affected by pH and flow rates. [ABSTRACT FROM AUTHOR]

In this paper, we present structural, magnetic, magnetocaloric, and critical study of perovskite La0.7Ag0.2Bi0.1MnO3 (LABMO) nanocrystalline compound synthesized by the sol–gel method. Temperature dependent magnetization measurements reveal the significant suppression of ferromagnetism in the LABMO sample upon Bi-doping on a La-site. The downturn in inverse magnetic susceptibility (χ−1) observed just above TC (236 K) in the paramagnetic regime corroborates the presence of short-range ferromagnetic correlations, which is the characteristic of the Griffith like phase below 270 K. The deviation from linear paramagnetic behavior in χ−1 implies the strong Griffith singularity. Furthermore, we have employed an integrated Maxwell's thermodynamic relation numerically and used isothermal magnetization data to determine the change in magnetic entropy at various magnetic fields. For a magnetic field change of 5 T, the value of maximum magnetic entropy change is found to be ∼6 J kg−1 K−1. We have also explored the critical behavior of the LABMO sample at transition temperatures using different theoretical models. The value of exponents β, γ, and δ does not fall into any known universality class. Despite this, the scaling relations show that interactions are renormalized around the Curie temperature (TC). The exponent n ≤ 2 extracted from field dependency on the magnetic entropy change confirms the second-order phase transition in LABMO. [ABSTRACT FROM AUTHOR]

In this paper, amorphous titanium dioxide (TiO2) thin films have been deposited on a commercially available Klarite substrate using the sol-gel process to produce surface-enhanced Raman scattering (SERS). The substrate consists of square arrays of micrometer-sized pyramidal pits in silicon with a gold coating. Several thin TiO2 layers have been deposited on the surface to study the influence of film thickness. Ultimately, we obtained information on SERS of an amorphous TiO2 layer by gold nanostructures, whose range is less than a few nanometers. Mechanisms responsible for the enhancement are the product of concomitant chemical and electromagnetic effects with an important contribution from plasmon-induced charge transfer. [ABSTRACT FROM AUTHOR]

In this paper, rutile phase titanium oxide/Sb-SnO2/anatase phase titanium oxide (TiO2 (R)/C-TiO2 (A)) heterostructured nanocomposites were prepared by a sol–gel method and a hydrothermal method. By optimizing the mass ratio between TiO2 (R) and C-TiO2 (A), the rod-ball heterostructures of TiO2 (R)/C-TiO2 (A) were formed and exhibited enhanced simulated sunlight-driven photocatalytic desulfurization performance. According to the results, the desulfurization rate of TiO2 (R)/C-TiO2 (A) was 93.98% after 60 min, which is higher than C-TiO2 (A) and TiO2 (R)/TiO2 (A). In addition, the photocatalytic recyclability test indicated that after three times the reuse of TiO2 (R)/C-TiO2 (A) could still reach 85.98%. The enhanced photocatalytic performance could be attributed to the double Z-scheme heterojunction in the TiO2 (R)/C-TiO2 (A) and the uniformly structure of rod array, which resulted in the higher separation efficiency of electrons and holes. Furthermore, the results of photocatalytic active radical species trapping experiments showed that the main substances in the photocatalytic reaction are ∙O2− and h+. This paper also established the double Z-scheme heterojunction reaction mechanism. [ABSTRACT FROM AUTHOR]

The methanol oxidation reaction has high energy density and the product is non‐toxic and harmless (CO2, H2O), making it become one of the targets of new fuel energy. To maximize the efficiency of the reaction, its key lies in the development of highly efficient catalysts. In this paper, we reviewed the types of methanol electrocatalytic oxidation catalysts in recent years, some new preparation methods, and the reaction mechanism of different types of catalyst systems, and discussed their structure‐activity relationships, laying the foundation for the development of highly efficient new catalysts in the future. And this paper is included on the types of catalysts (Pt‐based catalyst, Ni‐based catalyst, and other transition metal‐based catalyst) and preparation methods (Reduction method, sol‐gel method, in‐situ method), and discussed the catalytic mechanism which mainly starts from two aspects, one is adsorption‐desorption, the other is the bond between the catalyst, methanol, and the medium. Finally, the future challenges and opportunities of the electrocatalytic oxidation of methanol are discussed. [ABSTRACT FROM AUTHOR]

In This paper, butyl titanate and LiOH·H2O was used as titanium source and lithium source respectively. Li4Ti5O12 as battery negative material was prepared by sol-gel method. The effects of chelating agent (triethanolamine), raw material ratio, calcination temperature and calcination time on Li4Ti5O12 products were studied by single factor method. The experimental results show that The optimum synthetic conditions are as follows: the spinel Li4Ti5O12 with pure phase, uniform grain size, 100–200 nm particle size and no obvious agglomeration can be prepared under the conditions of molar ratio of lithium to titanium is 0.9–1.0, the calcination temperature can be 730–750 °C at 8 h. After assembled into CR2016 button cell, the first charge-discharge capacity of CR2016 button cell can reach 169 mAh/g at 0.1 C rate, which is very close to the theoretical value of 175 mAh/g. [ABSTRACT FROM AUTHOR]

Bio‐inspired synthetic method provides an effective shortcut to fabricate functional nanostructured materials with specific morphologies and designed functionalities. Natural cellulose substances (e. g. commercial laboratory cellulose filter paper) possesses unique three‐dimensionally cross‐linked porous structures and abundant functional groups for the functional modification on the surfaces. The deposition of metal oxide gel film on the surfaces of the cellulose nanofibers is facilely to be achieved through the surface sol‐gel process, resulting in metal oxide replicas of the initial cellulose substance or metal‐oxide/carbon nanocomposites. Moreover, the as‐deposited metal oxide gel films coated on the cellulose fiber surfaces provide ideal platforms for the further formation of specific functional assemblies, and eventually to the corresponding nanocomposite materials. Based on this methodology, various nanostructured composites were prepared and employed as anodic materials for lithium‐ion batteries, including metal‐oxides‐based (such as SnO2, TiO2, MoO3, FexOy, and SiO2) and Si‐based composites, as summarized in this personal account. Benefiting from the unique hierarchically porous network structures and the synergistic effects among the composite components of the anodic materials, the transfer of electrons/ions is accelerated and the structural stability of the electrode is enhanced, leading to the improved lithium storage performances and promoted cycling stability. [ABSTRACT FROM AUTHOR]

The paper presents the influence of ZrO2 coating on Ti6Al7Nb titanium alloy depending on the method of deposition. The coatings were made by sol-gel method and atomic layer deposition (ALD). Wettability tests, pitting corrosion assessment and electrochemical impedance spectroscopy (EIS) were carried out in the paper. Complementary macro- and microscopic observations, roughness analysis by profilometric method and atomic force microscopy (AFM) were made. Based on the results obtained, it can be concluded that the type of method of depositing the layer on the surface of the material has a significant influence on its properties and that it should be taken into account during the process of the material improvement. Drawing on the findings presented, it can be inferred that roughness has a significant impact upon the surface wetttability of the tested surfaces and their related corrosion resistance. The obtainment of hydrophobic surfaces is for smaller rougidity values. [ABSTRACT FROM AUTHOR]

α-Al 2 O 3 exhibits excellent physical and chemical stabilities and thus has a wide range of applications in various fields, however the potential application are often called off because of the grains coarsening and vermiculite structures originated from the high-temperature calcination process. In this paper, the calcination temperature has been significantly reduced by selecting the chelating anhydrous aluminium sols as the precursor. It was found that when the chelating agent was malic acid and the addition amount was 0.06 mol, the chelated structure had the highest content of [AlO 6 ] octahedra, which was more favourable for the low-temperature synthesis of α-Al 2 O 3. Kinetic analysis showed that the activation energy for the conversion of γ-Al 2 O 3 to α-Al 2 O 3 in this work was 398.09 kJ mol−1, which has been reduced by nearly 100 kJ mol−1 and thus the complete conversion of γ-Al 2 O 3 to α-Al 2 O 3 was achieved by holding at 900 °C for 2 h. The obtained spherical α-Al 2 O 3 nanoparticles, with a particle size of about 67.2 nm and a uniform morphology. After further extending the holding time to 30 h, the complete conversion of α-Al 2 O 3 was achieved at 825 °C, while the initial nucleation temperature was lower than 760 °C. [ABSTRACT FROM AUTHOR]

A CdSiO3:Tb3+ deep trap phosphor was prepared by a sol–gel method. The structural information of the prepared phosphors was characterized by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The optical properties of the Tb3+-doped CdSiO3 nanophosphors were investigated by fluorescence spectrophotometry. The afterglow time was more than 10.3 h in the case of Tb3+ doping. The stress–strain of this elastomer was enhanced after the phosphor was compounded with PDMS, and the energy release in the trap was accelerated under external force after applying stress to it, and this composite elastomer may possess mechanoluminescent properties. [ABSTRACT FROM AUTHOR]

CeO2@TiO2 core–shell nanostructures are synthesized at various titania contents by the sol–gel method. Such supports have been evaluated in the CO oxidation reaction to study lattice oxygen mobility. Also, FexOy/CeO2@TiO2 synthesized by the impregnation method to study the catalytic activities of the degradation of methylene blue and carmoisine dyes in Fenton-like processes. CeO2@TiO2 catalysts with a higher proportion of rutile have better activity in CO oxidation. The oxidation of dyes proceeds most efficiently on Fe-composites with titania containing a higher proportion of metastable phases of titania (anatase + brookite), in contrast to CO oxidation catalysts. The catalytic behavior of the materials was discussed to determine the role of the core–shell structure, ceria–titania interaction, and other particular qualities. The proposed systems can be promising catalysts for environmental protection. [ABSTRACT FROM AUTHOR]

Optical thermometry is a non-contact temperature sensing technique with widespread applications. It offers precise measurements without physical contact, making it ideal for situations where contact-based methods are impractical. However, improving the accuracy of optical thermometry remains an ongoing challenge. Herein, enhancing the thermometric properties of luminescent thermometers through novel materials or strategies is crucial for developing more precise sensors. Hence, the present study focuses on the application of four-mode luminescence thermometric techniques in sol–gel synthesized Er3+/Yb3+ co-doped Ba2GdV3O11 phosphors for optical temperature sensing in the temperature range of 298–573 K. The upconversion (UC) luminescence is achieved under excitations of 980 nm or 1550 nm, resulting in bright yellow-green emission in the visible spectral range. Temperature sensing is realized by exploiting the UC emissions of 4S3/2, 2H11/2 and 4F7/2 bands, which represent intensity ratios of thermally coupled levels (TCELs) and non-thermally coupled levels (NTCELs) of Er3+/Yb3+, along with the emission lifetimes at 4S3/2. The relative sensitivity (Sr) values for TCELs exhibit a gradual decrease with rising temperature, reaching a maximum of 1.1% K−1 for 980 nm excitation and 0.86% K−1 for 1550 nm excitation at 298 K. Conversely, for NTCELs, the highest Sr value observed is 0.9% K−1 at 298 K for 1550 nm excitation. Moreover, the emission lifetimes at 4S3/2 yield notably high Sr values of up to 5.0% μs K−1 (at 425 K). Furthermore, the studied phosphors have a sub-degree thermal resolution, making them excellent materials for accurate temperature sensing. Overall, this study provides a promising new direction for the development of more precise and reliable optical thermometry techniques, which could have important implications for a range of scientific and industrial optical temperature sensing applications. [ABSTRACT FROM AUTHOR]

Nano hydroxyapatite (n-HAp) and its composites have shown a great development in the field of tissue regeneration and in controlled drug delivery due to its good biocompatibility and bioactivity behavior. Furthermore, HAp-based nanocomposites enhance mechanical properties. These synthetic HAp nanocomposites can also be tailored to fabricate scaffold with controlled porosity which facilitate the growth of the cell in the field of tissue engineering. In this paper, we focus on the synthesis of nano hydroxyapatite (n-HAp) by sol-gel method. The synthesized nano powders were calcined at 500 o C and characterized by FT-IR, XRD and TEM. We have also described the synthesis of citric acid-based polyester by melt polycondensation method without adding catalyst. The monomers used were citric acid, 1,6-hexane diol and sebacic acid. The corresponding synthesized n-HAp/polyester composite have potential application in soft tissue engineering. The structures of polyester and its nanocomposite were studied by FT-IR and 1 H NMR spectral studies. The thermal and mechanical properties of polyester, composites and cytotoxicity activity (MTT assay) using vero cells were also studied. Porous scaffold of the nano HAp/Polyester was fabricated by solvent-casting particulate leaching technique which is useful in the development of tissue engineering applications. SEM and TEM studies were carried out for nano HAp, polyester, composites and scaffold. [ABSTRACT FROM AUTHOR]

In this paper, the LaAlO3 perovskite with large specific surface area and abundant surface oxygen vacancies is prepared by the hard template method, on which Ni metal nanoparticles and CaO alkaline additives are loaded. The generated catalyst is applied to the study of methane dry reforming. By analyzing and characterizing all catalysts prepared through BET, XRD, TEM, XPS, H2-TPR and other test methods, the LaAlO3 Hperovskite prepared by the hard template method can obtain both larger specific surface area and more abundant surface oxygen vacancies than the LaAlO3-C perovskite prepared by the traditional sol–gel method. As a result, the Ni-based catalysts supported by LaAlO3-H perovskite exhibit more favorable anti-sintering and anti-carbon deposition ability than Ni/LaAlO3-C catalyst. (Adding) CaO can enhance the adsorption of CO2 on Ni-based catalysts, so N-CaO/LaAlO3 catalyst possesses the most excellent anti-carbon deposition ability. [ABSTRACT FROM AUTHOR]

Under the background that the in-depth profile control technology is gradually applied in low-permeability fractured reservoirs, this paper regards block H of Changqing Oilfield as the research object, referring to the range of its physical parameters and field application data. Three common in-depth profile control agents (PCAs), nanosphere suspension, poly(ethylene glycol) single-phase gel particle (PEG) and cross-linked bulk gel and swelling particle (CBG-SP), are selected to investigate the compatibility between the fractured channels and the PCAs through a series of experiments. The experimental results show that the nanospheres with particle sizes of 100 nm and 300 nm have good injectivity and deep migration ability, which remains the overall core plugging rate at a high level. The residual resistance coefficient of 800 nm nanospheres decreases in a "cliff" manner along the injection direction due to the formation of blockage in the front section, resulting in a very low plugging rate in the rear section. The injection rate is an important parameter that affects the effect of PEG in the fractured channels. When the injection rate is lower than 0.1 mL/min, the plugging ability will be weakened, and if the injection rate is higher than 0.2 mL/min, the core plugging will occur. The appropriate injection rate will promote the better effect of PEG with the plugging rate > 90%. The average plugging rate of CBG-SP in fractured rock core is about 80%, and the overall control and displacement effect is good. Based on the experimental data of PCAs, the optimization criteria of slug configuration and pro-duction parameters are proposed. According to the principle "blocking, controlling and displacing", references are provided for PCAs screening and parameters selection of field implementation. [ABSTRACT FROM AUTHOR]

This paper reports on synthesis of undoped and Dy3+-doped cubic Y2O3 nanopowder via a neoteric and conducive citrate sol–gel technique. The size and morphology of prepared nanocrystallites are explored using XRD, TG-DSC, FTIR, FESEM, and HRTEM. Rietveld refinement is employed to affirm the preparation of as-synthesized Y2O3 nanocrystallites with cubic phase. The optical behavior of as-synthesized Y2O3, Dy3+-doped Y2O3 samples are studied in terms of absorbance, PL, and CIE coordinates. It is revealed that position of absorption peak is shifted towards higher wavelength side when Dy3+ ions are introduced in Y2O3 and further on annealing. In PL spectra, prominent emission is achieved in blue region at 485 and 369 nm under direct and indirect excitation wavelengths. Catalytic performance of the samples is also examined to de-colorize cotton blue dye. Annealing for a long time generated defect states which are helpful to accelerate the photocatalytic efficiency of the prepared nanopowder. [ABSTRACT FROM AUTHOR]

This paper has investigated the nanostructured samples of zinc oxide intended for use as a gas sensor. Experimental samples were obtained by the economical sol-gel method, suitable for large-scale production. The dependence of the efficiency of gas sensors based on zinc oxide on temperature was established. The electrical properties of experimental samples were investigated in the air in the range of values of the initial voltage of 5–30 V and at temperatures of 320, 370, and 450 K. It was established that the current-voltage characteristic for nanosized zinc oxide is non-ohmic, but the nature of the curves can change due to an increase in the operating temperature. The obtained experimental dependences are explained by the peculiarities of the morphology of the obtained nanostructured zinc oxide, which affects the value of the contact resistance in the structure. A large number of nanoscale particles leads to an increase in the number of energy barriers, which negatively affects the sensitivity of experimental samples to the gaseous medium. The study of the sensitivity of samples to the established gaseous medium, namely 100 ppm CO, was carried out. The electrical conductivity of zinc oxide is determined by oxygen vacancies that are electron donors, and, accordingly, the conductivity activation energy is determined by the donor levels formed by vacancies in the ZnO forbidden zone. During heating, there is a decrease in the resistance of the sample with increasing temperature; electrical conductivity is determined by the thermal generation of electrons. Understanding the dependence of the sensor sensitivity on temperature and the use of sensitive ZnO layers of different morphology will make it possible to recognize gaseous components in a complex mixture. [ABSTRACT FROM AUTHOR]

Multiferroic materials have attracted much attention because of their magnetoelectric coupling effect. In this paper, MnFe2O4 (MFO) magnetic particles and PbZr0.52Ti0.48O3 (PZT) ferroelectric particles were prepared by hydrothermal method and sol–gel method, respectively. PZT particles with different sizes were produced by tuning the sintering temperature, and on this basis, MFO-PZT multiferroic liquid was prepared by using monoamino ethoxy-coupling agent as the surfactants and dimethyl silicone oil as the carrier liquid. The effect of PZT particle size on magnetoelectric properties was studied. XRD and SEM show that the PZT particle and the MFO particle have no secondary phase, the size of MFO particle is 52 nm, and the PZT particle sizes are 0.38 μm, 1.07 μm, 1.68 μm, and 1.79 μm, respectively. When the particle size of PZT is 0.38 μm, a large dielectric constant of 8.39 of the multiferroic liquid was observed at low frequency (250 Hz). When the size of PZT is 1.79 μm, the liquid has the maximum saturation polarization intensity Ps ~ 0.0191 μC/cm2 and the maximum residual polarization intensity Pr ~ 0.0063 μC/cm2 was obtained. When a magnetic field is applied, the value of both Pr and Ps increases. When the size of PZT is 1.07 μm, the maximum magnetoelectric coupling coefficient of the liquid is 54.82 V/(cm·Oe). Compared with the same series of magnetoelectric materials, the magnetoelectric composite multiferroic liquid has a potential application prospect. [ABSTRACT FROM AUTHOR]

Creatinine, as a significant biomarker for kidney, thyroid, and muscle dysfunction-related diseases, detection is of great important meaning. In this paper, an enzyme-nanozyme cascade sensing platform was developed for visual creatinine detection. Perovskite oxide BiFeO3 synthesized by a sol–gel method was applied as a nanozyme, showing excellent peroxidase-like activity. During detection, creatinine was oxidized in turn by three natural enzymes (creatinase, creatininase, and sarcosine oxidase) to produce H2O2, and H2O2 was then catalyzed by the BiFeO3 nanozyme, resulting in the change of achromatous 3,3′,5,5′-tetramethylbenzidine (TMB) into blue oxidized TMB (oxTMB). Based on this principle, visual quantification of creatinine was realized. Due to the high stability and catalytic efficiency of nanozyme, the cascade sensing platform can be used to detect creatinine in a broad range of 0.5–150 μM with a detection limit of 0.09 μM. Meanwhile, thanks to the specificity of the natural enzymes, the platform exhibited admirable selectivity for creatinine determination despite the existence of a variety of interfering substances, which were successfully adopted to measure the level of creatinine in human serums. The cascade sensing platform is expected to serve the determination of a large number of biomarkers by simply alternating the natural enzymes. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) are a promising area of research among different new generations of photovoltaic technologies. Their manufacturing costs make them appealing in the PV industry compared to their alternatives. Although PSCs offer high efficiency in thin layers, they are still in the development phase. Hence, optimizing the thickness of each of their layers is a challenging research area. In this paper, we investigate the effect of the thickness of each layer on the photoelectric parameters of n-ZnO/p-CH3NH3PbI3/p-NiOx solar cell through various simulations. Using the Sol–Gel method, PSC structure can be formed in different thicknesses. Our aim is to identify a functional connection between those thicknesses and the optimum open-circuit voltage and short-circuit current. Simulation results show that the maximum efficiency is obtained using a perovskite layer thickness of 200 nm, an electronic transport layer (ETL) thickness of 60 nm, and a hole transport layer (HTL) thickness of 20 nm. Furthermore, the output power, fill factor, open-circuit voltage, and short-circuit current of this structure are 18.9 mW/cm2, 76.94%, 1.188 V, and 20.677 mA/cm2, respectively. The maximum open-circuit voltage achieved by a solar cell with perovskite, ETL and HTL layer thicknesses of (200 nm, 60 nm, and 60 nm) is 1.2 V. On the other hand, solar cells with the following thicknesses, 800 nm, 80 nm, and 40 nm, and 600 nm, 80 nm, and 80 nm, achieved a maximum short-circuit current density of 21.46 mA/cm2 and a fill factor of 83.35%. As a result, the maximum value of each of the photoelectric parameters is found in structures of different thicknesses. These encouraging results are another step further in the design and manufacturing journey of PSCs as a promising alternative to silicon PV. [ABSTRACT FROM AUTHOR]

Manganese copper ferrites belong to a family of ferrites with specific importance due to their high permeability values and low losses at low frequencies. In this paper, a series of ferrite samples has been synthesized using a novel and low cost sol-gel autocombustion route in order to systematically investigate the structural, compositional, morphological, and magnetic properties when zinc is substituted by copper in the series. X-ray diffraction reveals that all the samples have characteristic cubic spinel structure. The effect of zinc substitution at the copper site on the chemical bonding of the ferrite samples was investigated by Fourier transform infrared spectroscopy. Energy dispersive X-ray analysis was performed to determine the homogeneity and stoichiometric composition of elements present in the samples. Nanosized, uniformly shaped grains were evident from the images obtained using a scanning electron microscopy, which indirectly confirms the significance of the autocombustion synthesis technique employed in this paper. Magnetic properties determined using a vibrating sample magnetometer exhibited that zinc substitution could enhance the saturation magnetization of the samples, attributed to the substitution of a paramagnetic element (zinc) by a diamagnetic one (copper). [ABSTRACT FROM PUBLISHER]

In this paper, Pd modified WO thin film methanol sensor has been developed by sol-gel method. WCl chemical compound is used as a precursor. Spin coating method is employed for the preparation of the WO thin film on the Si substrate. The crystalline structure of the WO thin film is analyzed by scanning electron microscopy and X-ray diffraction techniques. The thin film sensor is fabricated at different annealing temperatures (400, 600 and 800 °C). The response magnitude of the WO thin film is studied at different operating temperatures (100-300 °C). It is observed that the operating temperature of Pd modified thin film sensor is 200 °C. It is also noticed that the maximum response magnitude of Pd modified WO thin film sensor is found at the annealing temperature of 600 °C. It is found that Pd modified WO thin film sensor are suitable for methanol vapour detection compare to unmodified WO thin film senor. [ABSTRACT FROM AUTHOR]

In this paper, \beta -Ga2O3 thin films were grown on a p-Si substrate using the sol–gel method. Structural characterization of the films was performed using X-ray diffraction. Electrical parameters such as breakdown field, interface traps density ( {D}_{\text {it}} ), and series resistance ( {R}_{s} ) were investigated at room temperature. The interface trap density was found to be 10^12 eV ^-1 cm ^-2 using the Hill–Coleman method. This result is valuable for MOS capacitor applications. Dielectric parameters were investigated in the wide frequency range (20 kHz–1 MHz) at room temperature. We observed that these parameters have a strong dependence on frequency and voltage. [ABSTRACT FROM PUBLISHER]

La2(Zr0.7Ce0.3)2O7 has been regarded as an ideal candidate for the next generation of thermal barrier coatings (TBCs) due to its prominent superiority. In this paper, the nano-sized La2(Zr0.7Ce0.3)2O7 was synthesized using two different synthetic routes: sol-gel and hydrothermal processes. Various techniques were utilized to assess the differences in the relevant thermophysical properties created by the different synthetic methods. According to the investigations, both samples exhibited pyrochlore structures with an excellent thermal stability. The sample synthesized via the hydrothermal method showed a more uniform particle size and morphology than that obtained through the sol-gel technique. The former also possessed a better sinter-resistance property, a more outstanding TEC (thermal expansion coefficient) and thermal conductivity, and a larger activation energy for crystal growth than the latter. The micro-strain of both samples showed an interesting change as the temperature increased, and 1200 °C was the turning point. Additionally, relative mechanisms were discussed in detail. [ABSTRACT FROM AUTHOR]

Vanadium pentoxide (V2O5) is one of the most popular electrochromic material for electrochromic devices due to its excellent storage capacity of lithium ions and unique properties of anodic/cathodic coloring. However, V2O5 generally has low conductivity, causing a long coloration/bleaching response time. Consequently, its practical use as a electrochromic material in practical industrial applications remains limited. In this paper, V2O5/Mxene intercalation films (VOM) were prepared by sol–gel method with spin-coating technology. The structure and morphology of the intercalation films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FESEM), and other testing techniques. The optical properties of the films were characterized by ultraviolet–visible (UV–Vis) spectroscopy, and the electrochemical properties were analyzed by cyclic voltammetry (CV) and chronoamperometry (CA). The results showed that the Mxene intercalation of V2O5 xerogel widened the interplanar distance. The bleaching time of the intercalation films was 3.20 s and the coloring time was 6.20 s when the Mxene doping was 3 wt%. Meanwhile, the transmittance contrast increased from 7.70 to 49.03% at 372 nm compared with the V2O5 xerogel films. [ABSTRACT FROM AUTHOR]

In this paper, Y–ZrO2–TiO2 photocatalyst was prepared by sol–gel method, the titanium source was tetrabutyl titanate, and the precursors were zirconium nitrate pentahydrate and yttrium nitrate hexahydrate. For the photocatalytic effect of Y–ZrO2–TiO2 to hydroquinone, these effects were investigated: doping ratios of Zr/Y, calcination conditions, pH, etc. And the materials were characterized by XRD, TEM-EDS, XPS, PL, ESR, etc. The results showed that the optimum preparation conditions of Y–ZrO2–TiO2 photocatalyst were as follows: the molar ratio of doping was Ti: Zr: Y = 100:6:0.5, the calcination temperature was 500 °C, and the calcination time was 2 h; the optimum reaction conditions were as follows: the dosage of Y–ZrO2–TiO2 was 1 g/L, and pH value was 6.96. The degradation rate of hydroquinone under 365-nm UV lamp for 50 min could reach 96.58%, while the degradation rates of pure TiO2, Y–TiO2, and ZrO2–TiO2 under the same conditions were 33.95%, 79.55%, and 90.30%, respectively. It can be seen that the addition of elements Zr and Y improves the photocatalytic performance of TiO2. [ABSTRACT FROM AUTHOR]

In this paper, potassium sodium niobate lead-free piezoelectric thin films were prepared by sol-gel method. The electric domain structure and optical band gap of the thin films were regulated by doping Mn. It is found that Mn doping increases the grain size and density of KNNLT piezoelectric film surface. In addition, Mn doping can regulate the electric domain of thin films. Increasing Mn doping concentration can regulate the size and distribution of electric domain, and the ratio of 71° electric domain increases with the increase of doping concentration. The results show that the optical band gap decreases gradually with the increase of doping amount when the annealing temperature is 650 °C. The lowest optical band gap reaches 3.426 eV, and is lower than the undoped KNNLT films. [ABSTRACT FROM AUTHOR]

The sol–gel dip-coating method is a cost-efficient way for the realization of thin films on a planar substrate. In this work, high-quality, low-loss, and low-surface roughness silica–titania thin films are deposited on a glass substrate with the sol–gel dip-coating method. This platform works in the visible to near-IR wavelength ranges and can be useful for several eye-catching photonic components. The paper is comprised of two parts: the first part deals with the development of a low-cost silica–titania waveguide system, whereas the second part provides detail on the numerical modeling of the SWG waveguide filter and SWG waveguide FP-sensor design. The SWG waveguide NIR-stopband filter can achieve an ER of >40 dB and 3-dB bandwidth of 110 nm designed at optimized parameters. The SWG waveguide-FP structure proposed in this work act as a refractive index sensor where the sensitivity is ~120 nm/RIU by reducing the width of the waveguide. This sensitivity can be further enhanced by reducing the waveguide height. We believe that this work is quite important for the realization of low-cost integrated photonic devices based on the silica–titania platform developed via the sol–gel dip-coating method. [ABSTRACT FROM AUTHOR]

In this paper, cerium was incorporated into polyhydroxyltriacetictin (PHTES) using the sol-gel method combined with electrospinning technology to prepare a series of composite oxide fiber catalysts SnxCe1−xO2 in different proportions. The structures and soot catalytic activities of SnxCe1−xO2 fibers were studied under loose contact conditions. When Ce entered the crystal lattice of SnO2, the structural symmetry of the SnO2 was destroyed, which inhibited the crystallization and grain growth of the fiber, and fiber catalysts with a larger specific surface area were obtained. Moreover, the introduction of Ce improved the number of oxygen vacancies and redox ability of the catalyst, thus promoting the catalytic activity of the catalyst for soot particles. In particular, among them, the Sn0.7Ce0.3O2 fiber catalysts had the strongest catalytic oxidation ability regarding soot particles and could oxidize soot particles at a lower temperature and faster catalytic rate. The results of the temperature-programmed oxidation of Sn0.7Ce0.3O2 fiber catalyst, conducted three times under the same conditions, were basically consistent, indicating that the experimental results are reliable and repeatable. In addition, the Sn0.7Ce0.3O2 fiber catalyst showed good cycle stability. [ABSTRACT FROM AUTHOR]

In this paper, the GdCrO3 polycrystalline samples with different particle sizes were prepared by the sol–gel method and the structure, vacancy defects, magnetocaloric property, dielectric property were investigated in detail. The results indicate that the lattice constant and vacancy defects can be affected greatly by the particle size. With the particle sizes increases, the magnetic entropy becomes larger at first, and then it decreases accompanying particle size becomes larger than 395 nm. That is, the d = 395 nm sample presents the best magnetocaloric property and the maximum magnetic entropy (− ΔSM) and the refrigerant capacity (RCP) at T = 3 K and H = 3 T condition is 33.41 J·kg−1 K−1 and 552.4 J kg−1. The temperature and magnetic field dependent permittivity also confirm the magneto-dielectric effect of the prepared GdCrO3. As the particle size increases, the coupling coefficient enhanced continuously. Especially for the d = 485 nm sample, a small field of 1 T could cause the dielectric constant increases by about 10%. This work suggests that increasing the particle size is an effective method for improving the magnetocaloric and magnetoelectric properties of GdCrO3. [ABSTRACT FROM AUTHOR]

In this paper, an ultra-scratch-resistant, hydrophobic and transparent coating was fabricated by the sol–gel method using (3-Glycidyloxypropyl) triethoxysilane (GPTES) and curing agents. When the silanol was condensated, the ring-opening reaction of the epoxy groups also took place, which formed a double-cross-linked network (Si–O–Si and R3N). This network structure restricted the molecule chains from being twisted or dislocated, resulting in a great improvement of the abrasion resistance of the coating. A pencil hardness grade up to 8H was obtained. The coating also showed excellent stability after being soaked in pH = 2 and pH = 12 solutions, seawater and acetone, respectively. In addition, a water contact angle of 121° was obtained by post-treatment with hexamethyldisilazane (HMDS). The average transmittance of the coating reached to 90% in the wavelength range of 400~800 nm, nearly identical to the glass substrate. With multiple desirable properties and a simple fabrication process, this low-cost coating shows great potential in many practical applications. [ABSTRACT FROM AUTHOR]

In this paper, we report that hafnium oxide nanoparticles with different copper contents (0.00, 0.02, 0.04, and 0.06%) are successfully synthesized by sol–gel technique. The influence of the copper concentration and observed the morphological and structural changes of the obtained nanoparticles. For characterization, XRD observed that the crystalline structure depends on the doping content. The synthesis samples are undoped hafnium and copper-doped hafnium oxide nanoparticles, which crystallographic change from cubic to monoclinic phase with increasing doping concentration. The presence of Hf, Cu, and O in the synthesis sample was confirmed by EDS analysis. Energy gaps of the synthesized samples were estimated from the ultraviolet–visible absorption spectrum as well as Tauc's plot which infers that the energy gap decreases with the increase of Cu content. Fourier transform infrared spectrum confirms the cadmium dopant through peak shifting from 538 to 650 cm−1. PL showed an emission peak at 360 nm that strongly confirmed the UV region and intensity of emission peak increase with increase dopant. SEM and TEM study reveal that the synthesized samples consist of spherical morphology and the particle size varies between 34 and 43 nm. The electrical resistivity decreases from 28 to 16Ω with doping content increasing which indicates that the conductivity of the nanomaterial is improved. [ABSTRACT FROM AUTHOR]

In this paper, undoped, Al-, and In-doped zinc oxide thin films were deposited. Film growth was performed using the sol–gel technique. The method included (a) preparing homogeneous and stable solutions of zinc acetate 2-hydrate, (b) mixing them with aluminum nitrate and indium acetate in 2-methoxyethanol and 2-aminoethanol solutions with various concentrations, and (c) spin coating them onto transparent glass substrates. After thermal annealing, the films showed a high transparency (80–90%) and good stability. Using typical diagnostic tools, the structural, morphological, optical, and electrical film properties were investigated and linked to the dopant type, and concentrations in view of optoelectronics were investigated. [ABSTRACT FROM AUTHOR]

Purpose: Among various metal oxide nano particles, MgO NPs and ZnO nanoparticles (NPs) in particular are gaining increasing attention due to their multifunctional characteristics, low cost and compatibility with textile materials. Each type of nanoparticle excels over others in certain properties. As such, it is often crucial to carry out comparative studies of NPs to identify the one showing higher efficiency/output for particular applications of textile products. Design/methodology/approach: In the investigation reported in this paper, ZnO NPs and MgO NPs were synthesised via sol-gel technique and characterised. For comparative analysis, the synthesised NPs were evaluated for multiple properties using standard procedures before and after being applied on cotton fabrics by a dip-pad-dry-cure method. Findings: XRD and FTIR analyses confirmed the successful synthesis of ZnO and MgO NPs. Homogeneous formation of desired NPs and their dense and uniform deposition on the cotton fibre surface were observed using SEM. ZnO NPs and MgO NPs coatings on cotton were observed to significantly enhance self-cleaning/stain removal properties achieving Grade 5 and Grade 4 categories, respectively. In terms of ultraviolet (UV) protection, ZnO or MgO NP coated fabrics showed UPF values of greater than 50, i.e. excellent in blocking UV rays. MgO NPs exhibited 20% cleaning efficiency in treating reactive dye wastewater against ZnO NPs which were 4% efficient in the same treatment, so MgO was more suitable for such type of treatments at low cost. Both NPs were able to impart multifunctionality to cotton fabrics as per requirement of the end products. However, ZnO NPs were better for stain removal from the fabrics while MgO NPs were appropriate for UV blocking. Originality/value: It was therefore clear that multifunctional textile products could be developed by employing a single type of cost effective and efficient nano particles. [ABSTRACT FROM AUTHOR]

This paper represents a general study of titanate nanotubes (TiNTs) which are among the most important materials in the field of catalysis. This research work covers more than 100 publications about the formulation, characterisation and most recent applications of TiNTs. TiNTs can be prepared by different methods, namely the anodic deposition, sol‐gel template synthesis and alkaline hydrothermal treatment. The present study focuses on the preparation of this tubular structure by alkaline treatment, using the latest and most recent processes that have been introduced in this method (stirring, acid nature, annealing temperature, etc). The surface properties, such as the point of zero charge (P.Z.C), acid‐base nature and light absorption, of TiNTs are also evoked. In the end, some recent and important TiNTs applications in the field of renewable energies are reported (H2 production and methanation). In addition, NO reduction, CO oxidation, photocatalysis and organic synthesis are also mentioned. Therefore, it may be said that this paper is a structured study about TiNTs for the purpose of making the reader aware of their importance, understand their synthesis, and know their scope of applications. To conclude, the most important data, acquired through various characterization techniques, are provided. [ABSTRACT FROM AUTHOR]

In this paper, novel core–shell (CS) structure composites SiO2@ANA-Si–Eu and SiO2@ANA-Si–Eu–L (L = phen, TTA) were prepared by the condensation of 5-N-bis(amidopropyltriethoxysilyl) nicotinic acid (HOOCC5H4NN(CONH(CH2)3Si(OCH2CH3)3)2, abbreviated as ANA-Si) and a SiO2 microsphere with a diameter of 200 nm in the absence of surfactants. The as-synthesized CS structure composites possess good dispersion, uniform size and excellent luminescence properties. Furthermore, silica modified core–shell–shell (CSS) structure composites SiO2@ANA-Si–Eu@SiO2 and SiO2@ANA-Si–Eu–L@SiO2 were successfully prepared by a sol–gel method using CS structure composites as the core and amorphous silica as the shell. Compared with the CS structure composites, CSS structure composites exhibited a stronger luminescence intensity in the solid state. Furthermore, an improved luminescence stability property of the CSS structure composites was found in aqueous medium. CSS structure composites exhibited improved luminescence, high stability and good solubility, which provided potential for their wide use in advanced phosphors, molecular biomarkers and luminescent tracers. [ABSTRACT FROM AUTHOR]

In this paper, we reported, for the first time, the preparation of La2MnTiO6 double perovskite nanostructures using a simple sol–gel method in the presence of citric acid as the size controlling agent. The crystalline structure, morphology, and elemental composition of the prepared samples were characterized by XRD, TEM, FE-SEM, and EDX mapping analysis. Owing to superior electronic properties of the double perovskite, we used the prepared samples in the photocatalytic degradation of acid blue 113 (AB 113) under visible light irradiation. The photocatalytic degradation of AB 113 was nearly 72% after 120 min irradiation. Also, the effects of the photocatalyst amount and pH value of the dye solution were studied. Investigation on the photocatalytic degradation mechanism using various radical scavenging agents revealed that the photo-generated holes are the dominant oxidants for the degradation of AB 113. The reusability experiment showed that the prepared sample has good recyclability even for 6 reaction cycles. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to provide an investigation on a new kind of photocatalytic material, namely, the porous ceramic foam loading titanium dioxide, which can make an effective photocatalytic degradation of the methyl orange (MO) solution in the wastewater. Design/methodology/approach: The natural zeolite powder has been used as the primary raw material to produce a sort of lightweight porous ceramic foam by impregnating polymer foam in slurry and then sintering. With the sol-gel method, a kind of open-cell reticular porous ceramic foam loading TiO2 film was obtained having a good photocatalytic action, and the resultant porous composite product presents the bulk density of 0.3~0.6 g/cm3 to be able to float on water. Findings: The MO could tend to be completely degraded in the solution with a certain concentration by the TiO2-loaded ceramic foam irradiated with ultraviolet light, and this composite foam was found to have high degradation efficiency for the MO solution in a wide range of pH. Originality/value: This work presents a TiO2-loaded ceramic foam that can effectively photo-catalyze to degrade the MO in water, and the degradation efficiency were examined under different conditions of the MO solution with various pH values. [ABSTRACT FROM AUTHOR]

This paper presents the most used processes for the synthesis of hydroxyapatite from aqueous solutions: chemical precipitation, the hydrothermal process and the sol-gel method. The experimental part includes the synthesis of hydroxyapatite by chemical precipitation. The obtained results confirm the obtaining of a ceramic with a high purity and a high degree of crystallization. [ABSTRACT FROM AUTHOR]

Purpose: The main purpose of this publication is to bring closer method of synthesis and examining basic properties of TiO2, ZnO and NiO nanoparticles (NPs), and investigate their possible biomedical application. Design/methodology/approach: Nanopowders were made with sol-gel method. Surface morphology studies of the obtained materials were made using Zeiss's Supra 35 scanning electron microscope and the structure using S/TEM TITAN 80-300 transmission electron microscope. In order to confirm the chemical composition of observed nanopowders, qualitative tests were performed by means of spectroscopy of scattered X -ray energy using the Energy Dispersive Spectrometer (EDS). The DLS (Dynamic Light Scattering) method was used to analyse the particle size distribution using the AntonPaar Litesizer 500 nanoparticle size analyser. Changes in particle size distribution at elevated temperatures were also observed. The TiO2, ZnO and NiO NPs with spherical shape were successfully produced by sol-gel method. Findings: The diameter of the as prepared nanoparticles does not exceed 25 nm which is confirmed by the TEM analysis. The highest proportion among the agglomerates of the nanoparticles has been shown to show those with a diameter of 80 to 125 nm. The qualitative analysis of EDS confirmed the chemical composition of the material. Practical implications: Nanoparticles (NPs) has been receiving an incrementally increasing interest within biomedical fields researchers. Nanoparticles properties (physical, chemical, mechanical, optical, electrical, magnetic, etc.) are different from the properties of their counterparts with a larger particle size. Originality/value: The nanoparticles were prepared using sol-gel method which allows the particle size to be controlled in a simple way. [ABSTRACT FROM AUTHOR]

Oxidation of sp3 C–H bonds has attracted increasing attention, and the aim of our work is to prepare catalysts for oxidation of sp3 C–H bonds using O2 without an initiator. In this paper, a series of Co–Cu bimetal oxides with different Co/Cu ratios were synthesized by a sol–gel method and tested for catalytic oxidation of fluorene to fluorenone using molecular oxygen as an oxidant in the absence of a radical initiator. The best catalytic performance was achieved over the Co0.7Cu0.3 catalyst and the catalysts could be reused without significant loss of the catalytic activity. The characterization results indicated that some Cu entered the Co3O4 lattices, leading to more high-valence metal ion sites (Co3+ and Cu2+) and surface oxygen species (O2−, O22−, and O−) as well as promoted redox ability, which all enhanced the catalytic activity. In addition, the catalysts were also efficient for the oxidation of other benzylic C–H containing aromatic hydrocarbons such as tetralin, indan, diphenylmethane and ethylbenzene. [ABSTRACT FROM AUTHOR]