Dioxide Composite Materials Research Articles

Heat transfer analysis of thermal radiative over a stretching curved surface using molybdenum disulfide and silicon dioxide composite material under the influence of solar radiation

PurposeThe primary focus of this study is to tackle a critical industry issue concerning energy inefficiency. This is achieved through an investigation into enhancing heat transfer in solar radiation phenomena on a curved surface. The problem formulation of governing equations includes the combined effects of thermal relaxation, Newtonian heating, radiation mechanism, and Darcy-Forchheimer to enhance the uniqueness of the model. This research employs the Cattaneo–Christov heat theory model to investigate the thermal flux via utilizing the above-mentioned phenomenon with a purpose of advancing thermal technology. A mixture of silicon dioxide (SiO_2)\\ and Molybdenum disulfide (MoS_2) is considered for the nanoparticle’s thermal propagation in base solvent propylene glycol. The simulation of the modeled equations is solved using the Shifted Legendre collocation scheme (SLCS). The findings show that, the solar radiation effects boosted the heating performance of the hybrid nanofluid. Furthermore, the heat transmission progress increases against the curvature and thermal relaxation parameter.Design/methodology/approachShifted Legendre collocation scheme (SLCS) is utilized to solve the simulation of the modeled equations.FindingsThe findings show that, the solar radiation effects boosted the heating performance of the hybrid nanofluid. The heat transmission progress increase against the curvature and thermal relaxation parameter.Originality/valueThis research employs the Cattaneo–Christov heat theory model to investigate the thermal flux via utilizing the above-mentioned phenomenon with a purpose of advancing thermal technology.

Obtaining and Studying In Situ a Chitosan–Titanium Dioxide Composite Material for Agriculture

Obtaining and Studying In Situ a Chitosan–Titanium Dioxide Composite Material for Agriculture

Evaluation of quantum dot composite graphene /Titanium oxide enhanced UV aging resistance modified asphalt

The long-term ultraviolet radiation of asphalt pavement leads to performance degradation, which seriously affects the service life. However, inorganic nanoparticles as anti-ultraviolet aging modifiers can only respond to some ultraviolet light, resulting in not high absorption rate of ultraviolet light. In this study, a variety of nano-quantum dots were introduced to modify graphene/titanium dioxide to further improve the ultraviolet absorption capacity of inorganic nanoparticles and slow down the aging of asphalt pavement caused by ultraviolet light. The effect and mechanism of the special heterojunction structure formed by a variety of quantum dots on the aging resistance and rheological properties of asphalt were investigated. The results show that the introduction of various quantum dots improves the ultraviolet absorption capacity of nano-TiO2. Although the thermal stability of nanographene/titanium dioxide composites decreases, its initial decomposition temperature is much higher than the test temperature of the asphalt mixture. From the macroscopic rheological test, the nano-graphene / titanium dioxide composite material further expands the improvement effect on the high-temperature rheological properties of asphalt, and secondly slows down the low-temperature crack resistance of nano-TiO2 modified asphalt. From the microscopic test, the introduction of various quantum dots greatly reduces the sulfoxide index (SI), carbonyl index (CI) and root mean square roughness Sq of modified asphalt, effectively slowing down the aging effect of ultraviolet light on asphalt, and ensuring the service state of asphalt pavement in a complex environment.

Reduced Graphene Oxide on Activated Carbon-Manganese Dioxide Composite Materials for High-Performance Supercapacitor Electrodes

This study presents the addition of reduced graphene oxide (rGO) on the surface of activated carbon-manganese dioxide (ACMnO2) composite material via high-temperature variations of 350 to 450 °C to increase the specific capacitance of the ACMnO2/rGO composite electrode. The composite material is synthesized by coating the slurry mixture on the aluminum sheet using a 2-step doctor blade method with polyvinylidene difluoride (PVDF) material and dimethylformamide (DMF) solution as a binder. Then symmetric supercapacitor is fabricated using filter paper as a separator and 3M potassium hydroxide (KOH) solution as an electrolyte. The composite material analysis is characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) as well as cyclic voltammetry (CV) for the electrochemical properties. The ACMnO2/rGO composite electrode at a temperature variation of 350 °C showed the highest specific capacitance of 459.79 F g-1 at a scan rate of 9 mV s-1 with an energy density of 63.859 Wh kg-1. The addition of rGO on the surface of the ACMnO2 composite material increased the specific capacitance by about 58% compared to without rGO, showing promises for high-performance supercapacitor electrodes.

Preparation and Mechanical Characterisation of Basalt Fabric, Epoxy, and Silicon Dioxide Composite Materials

Preparation and Mechanical Characterisation of Basalt Fabric, Epoxy, and Silicon Dioxide Composite Materials

Preparation of reduced graphene oxide/titanium dioxide composite materials and its application in the treatment of oily wastewater

In current study, a reduced graphene oxide/titanium dioxide (RGO/TiO2) with good demulsification performance was prepared. The structure and morphology of RGO/TiO2 was characterized by Fourier transform infrared spectroscopy (FT-IR), UV–vis absorption spectra (UV), X-ray diffraction spectra (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectrometer (EDS). The bottle test showed that the light transmittance was up to 79.1 % when the concentration of RGO/TiO2 was 500 mg/L and the settling time was 30 min at ambient temperature. Furthermore, it had high salt tolerance under acidic and neutral conditions. The wettability, interfacial activity, dynamic interfacial tension (IFT), zeta potential, self-assemble of the interfacial film and microscopic analysis were further studied to explore the demulsification mechanism. The possible demulsification mechanism exhibited that RGO/TiO2 could be rapidly migrated to the oil-water interface and then to destroy the stability of oil droplets by adsorbing or replacing asphaltenes through π-π interaction. The finding in this work can bring a better understanding on the demulsification mechanism and provide a promising demulsifier to treat the oily wastewater.

Poly(3-octylthiophene-2,5-diyl) - nanosized ruthenium dioxide composite material as solid-contact layer in polymer membrane-based K+-selective electrodes

This work presents the novel and universal approach to designing all-solid-state ISEs with PVC membrane by implementing the conducting polymer-nanoparticles of ceramic dioxide composite material as solid-contact layer. Properties of ruthenium dioxide RuO2 and poly(3-octylthiophene-2,5-diyl) (POT) were combined into one mediation layer in K+-selective electrodes what resulted in their great performance parameters. The fast and low-cost method of composite preparation and electrodes fabrication was presented in the article.The layers' microstructure, wettability and electrical parameters were studied using various methods. RuO2 particles turned out to enhance polymer's electrical and hydrophobic properties and allowed to obtain superhydrophobic layer of high electrical capacity which is favorable for solid contact. The SEM and TEM scans revealed the nano-sized particles of RuO2 contributing to the large surface area and the wettability test exposed the contact angle of 149°. Electrical capacitance obtained for the RuO2-POT composite material was as high as 1.17 mF and allowed to obtain stable potentiometric response of electrodes, while the superhydrophobic properties of the layer resulted in their great performance during the water-layer test.

Characterisation and properties of visible light-active bismuth oxide-titania composite photocatalysts

Bismuth oxide – titanium dioxide composite materials were produced by pulsed DC reactive magnetron sputtering onto two types of commercially available titanium dioxide nanoparticles. The use of an oscillating bowl enabled deposition of bismuth oxide uniformly onto loose powders, in contrast to solid substrates typically used for the conventional magnetron sputtering processes. Variation of the deposition time allowed the production of composite materials with different amounts of bismuth oxide. The composite materials, as well as uncoated titania powders, were extensively analysed by a range of analytical techniques, including SEM/EDX, XRD, BET, XPS, TEM and UV–visible diffuse reflectance spectroscopy. Photocatalytic properties of the materials were assessed under simulated visible light irradiation via degradation of acetone and methanol through measurements of carbon dioxide evolution. Additionally, the composite materials were characterised with a newly developed technique of reversed double-beam photoacoustic spectroscopy in order to obtain information on the distribution of electron traps. Bismuth oxide was found in crystalline β-Bi2O3 form on both types of substrates without any additional heat treatment applied. Though the distribution of bismuth oxide on titanium dioxide was found to depend strongly on particle size and deposition time used, the composite materials exhibited significantly enhanced visible light photocatalytic activity compared to either of the commercial titania materials used as a substrate.

Thorium adsorption on graphene oxide nanoribbons/manganese dioxide composite material

A functional graphene oxide nanoribbons/manganese dioxide composite material (MnO2-GONRs) was synthesized by hydrothermal method using graphene oxide nanoribbons (GONRs) as raw material which were formed by longitudinal unzipping of multi-walled carbon nanotubes with KMnO4 and H2SO4. The microstructure of MnO2-GONRs was characterized by SEM and FT-IR. The various factors affecting the adsorption of Th(IV) in aqueous solution such as pH, solid–liquid ratio, contact time, initial concentration and temperature were investigated by batch static adsorption experiments, and the adsorption mechanism is also discussed. The results showed that MnO2-GONRs had a good adsorption effect on Th(IV) with a maximum adsorption of 166.11 mg/g.

Photocatalytic production of hydrogen from methanol and saccharides using carbon nanotube-TiO2 catalysts

Carbon nanotube-titanium dioxide composite materials were produced by two routes: hydration–dehydration and one-pot oxidation. Au, Pt, Ir and Pd were loaded on TiO2-based materials by an incipient wetness method. The resulting materials were calcined and afterwards reduced at two distinct temperatures, 473 and 673K. Characterization was carried out by temperature programmed desorption, infrared and UV–Vis spectroscopy, N2 adsorption, SEM and TEM. Compared with reference TiO2, composite catalysts presented increased activity for photocatalytic production of H2 from methanol solutions. The highest activity was obtained for the Pt-loaded composite produced by the one-pot synthesis method, with 485μmol of H2 being generated after two hours of irradiation, contrasting with 205μmol of H2 obtained using Pt/TiO2. This synergic effect was discussed in terms of the action of carbon nanotubes as dispersing media for TiO2 particles as well as their action as photosensitizers. The relative efficiency of the catalysts was related to the work function of each metal and the sizes of the metal nanoparticles. H2 generation from photocatalytic reforming of saccharides, namely arabinose, glucose, fructose and cellobiose was performed using TiO2 and CNT-TiO2 based catalysts. The relative efficiency of H2 production from these biomass-derived compounds has been discussed based on their structural arrangement, H:C ratio and availability of α-hydrogens.

Preparation and characterization of polyaniline+TiO2 composite films

In this work, we have prepared electrochemically and studied a composite materials based on an organic conducting polymer, polyaniline (PANI), in which inorganic semiconductor titanium dioxide (TiO2) particles were incorporated with different concentrations. The polyaniline/titanium dioxide composite material which had been deposited by cyclic voltammetry on substrates of indium tin oxide was then characterized. The cyclic voltammogram showed one redox couple characteristic of the oxidation and reduction states of the produced composite material. The impedance spectroscopy study showed that the resistance of the film increases with the TiO2 cocntent incorporated in the polymer. The incorporation of TiO2 in PANI covering the surfaces was confirmed by the scanning electron microscopy and the energy dispersive X-ray analysis. The morphological analysis of the film surfaces showed that the TiO2 nanoparticle increased the roughness. These observations allow to consider a new approach to improve the physicochemical properties of the interface between the organic and inorganic material. The I–V characteristics of PANI+TiO2 heterostructure diode showed the nonlinear nature of the I–V curve of PANI+TiO2 heterostructure device.

Preparation and Performance of Myristic Acid/Silicon Dioxide Composites as Thermal Energy Storage Materials

The myristic acid/silicon dioxide composite materials were prepared by sol-gel methods. The myristic acid was used as the phase change material for thermal energy storage, with the SiO2 acting as the supporting material. The structural analysis of these form-stable myristic acid /SiO2 composite phase change materials was carried out using Fourier transformation infrared spectroscope (FT-IR).The microstructure of the form-stable composite phase change materials was observed by a scanning electronic microscope (SEM). The thermal properties was investigated by a differential scanning calorimeter (DSC).The SEM results showed that the myristic acid was well dispersed in the porous network of SiO2. And the new nanocomposite material has favorable thermal storage capacity and can be applied to solar energy storage, industrial waste heat, recovery of waste heat and as civilian structural materials.

Photoactivity of nano-structured calcium silicate–titanium dioxide composite materials

Titanium dioxide TiO2 in the anatase form and nanosize crystals is well known for its photoactivity. The electron–hole pairs produced in the TiO2 as a result of irradiation by UV light (sunlight) have a sufficiently high redox potential to produce hydroxyl radicals in the presence of H2O that can oxidise organic compounds to CO2. Thus TiO2 sees applications in water and air purification and in self-cleaning systems. For practical purposes in many applications, it is necessary to bind the TiO2 nanocrystals onto a substrate while at the same time ensuring maximum exposure of the TiO2 surface to the UV light (sunlight) and the medium containing the organic material to be oxidised. Here we report the development and characterisation of a novel nano-structured calcium silicate–TiO2 composite material comprising a proprietary nano-structured calcium silicate host material which has an open framework structure and a large surface area to which anatase TiO2 has been attached during synthesis. The composite material has been characterised and tested in the photocatalytic degradation of phenolphthalein. The highest photocatalytic activity was observed when the calcium silicate–TiO2 composite material contained discrete TiO2 particles of about 30–100 nm in size on the surface of the silicate host.

Synthesis of nano B 2O 3/TiO 2 composite material as a new solid phase extractor and its application to preconcentration and separation of cadmium

A new solid phase extractor, nano-scale diboron trioxide/titanium dioxide composite material, was synthesized and used for separation and/or preconcentration of trace cadmium ion from various samples. The characterization of the synthesized material was performed by scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray diffractometer methods (XRD). The specific surface area of the material was also determined and found as 3.4 m 2/g. Analytical parameters including pH of sample solution, sample volume, flow rate of sample solution, volume and concentration of eluent for the column solid phase extraction (SPE) procedure were examined. The effect of common matrix ions on the recovery of the cadmium has also been investigated and found that they did not interfere on cadmium preconcentration. Under the optimum experimental conditions, preconcentration factor and analytical detection limit were determined as 50 and 1.44 μg/L, respectively. The reusability (stabile up to 100 run) and adsorption capacity (49 mg/g) of the sorbent were excellent. The accuracy of the method was confirmed by analyzing certified reference materials (Tea leaves GBW-07605). The results demonstrated good agreement with the certified values (relative error <10%). The precision of the method was also satisfactory. The recovery of cadmium under the optimum conditions was found to be 96 ± 3% at 95% confidence level. The method was applied for the determination of cadmium in tap water and tea leaves.