Dioxide Hybrid Research Articles

Active dual quasi-BICs in a dielectric metasurface with VO2 for slow light and optical modulation.

We investigate the temperature tunable dual quasi-bound states in the continuum (qBICs) in a silicon/vanadium dioxide (Si/VO2) hybrid metasurface with Q-factor being as large as 9.3 × 106 and 2.8 × 107 by breaking the in-plane C2 symmetry. The far-field scattering of multipoles and near-field distributions confirm that the toroidal dipole and magnetic quadrupole dominate the dual qBICs resonance. The high performance of slow light with ultralarge group index exceeding 5.6 × 105 and the inverse quadratic law between the group index and asymmetric parameter are achieved. By temperature tuning of the VO2 thin film at the sub-10 K scale, a modulation depth of 90% and the ON/OFF ratio exceeding 12.8 dB are obtained. The proposed temperature tunable dual qBICs have potential applications in the fields of tunable slow light, temperature switches, and sensors.

Graphene oxide/silicon dioxide (GO/SiO2) hybrid coating on zirconia ceramic for sustainable water desalination

Hybrid membranes combining graphene oxide (GO) and silicon dioxide (SiO2) were successfully developed for pervaporation desalination using porous zircon tube substrates. These GO/SiO2 membranes were carefully designed by adjusting the amount of GO and the pH levels during the dip-coating process on the zircon tube surface. The study aimed to investigate how varying amounts of GO and pH levels affect the membranes' properties and desalination performance. The results indicate that raising the pH level decreases the membranes' hydrophilicity and enhances their stability. Conversely, increasing the amount of GO increases the membranes’ hydrophilicity and reduces their pore size. Higher pH levels and GO amounts resulted in better salt rejection but lower water flux. Among the tested membranes, GS-6 (0.3 % GO/SiO2, pH 6) achieved the highest salt rejection rate of 99.96 % at 30 °C with a 1 % NaCl feed concentration. In contrast, GS-1 (0.1 % GO/SiO2, pH 4) showed the highest water flux of 8.54 kg m−2 h−1 at 60 °C with the same feed concentration. Increasing the temperature led to decreased salt rejection but increased water flux. Additionally, higher feed concentrations lowered both salt rejection and water flux.

Chitosan grafted with gallic acid and cerium dioxide hybrid nanocomposites as environmentally friendly corrosion inhibitors for mild steel: An experimental and computational study

Chitosan grafted with gallic acid (CS-GA), along with CS-GA doped with CeO2 nanoparticles (CS-GA-CeO2) were synthesized as novel environmentally friendly mild steel corrosion inhibitors. The formation of these derivatives was confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), hydrogen nuclear magnetic resonance spectroscopy (1H NMR), and thermal analysis (TGA). Based on potentiodynamic polarization curves (PDP) measurements, the inhibitors acted primarily as hybrid inhibitors, while following the Langmuir adsorption theory model. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy(XPS) and 3D surface profiles, confirmed that CS-GA-CeO2 adsorbed on the mild steel forming a protective layer thus preventing the invasion of corrosive media. The corrosion protection mechanism of chitosan derivatives was investigated by molecular dynamics simulations. Electrochemical measurements were used to investigate the corrosion inhibition by CS-GA and CS-GA-CeO2 on mild steel in a 3.5 % NaCl solution. At room temperature, the highest inhibition efficiency (93.58 %) was achieved at 200 ppm CS-GA-CeO2. Modified chitosan nanocomposites were confirmed as promising corrosion inhibitors.

Physical properties of rutile-TiO2 Nanoparticles and effect on PVA/SiO2 hybrid films synthesized by sol-gel method

We use an ab-initio approach to analyze the structural, electronic band structure, and thermoelectric properties of titanium dioxide (TiO2 in rutile phase), and we then use rutile-TiO2 nanoparticles to determine its effects on sol-gel-produced polyvinyl alcohol/silicon dioxide (PVA/SiO2) hybrid films. The synthesis of hybrid films involved the incorporation of 1 % rutile-TiO2 nanoparticles in the PVA/SiO2 matrix. The thermoelectric properties of the resulting hybrid films were characterized by Seebeck coefficient measurements, as well as electrical and thermal conductivities. The synthesis of PVA/SiO2/Nano-TiO2 films was accomplished with success. The chemical bonds have amply demonstrated that the PVA backbone is connected to the (SiO2-TiO2) network. TGA testing indicates that hybrid films are more resistant to higher temperatures than pure PVA films. SiO2 nanoparticles reveal more effective loading to improve dielectric characteristics compared to TiO2. The best results are obtained in cases of mechanical, thermal and electrical insulation when both nanofillers are integrated into the polymer matrix. The findings show that the thermoelectric performance of PVA/SiO2 hybrid films is improved by the addition of (1 %) rutile-TiO2 nanoparticles in the rutile phase. This study provides insights into the potential applications of rutile-TiO2 nanoparticles in enhancing the thermoelectric properties of hybrid materials and opens up avenues for further research in this area, and contributes to the growing body of knowledge on enhancing the thermoelectric properties of materials by incorporating rutile-TiO2 nanoparticles into hybrid films synthesized by the sol-gel method.

Switchable dual ultra-broadband perfect absorber based on graphene and vanadium dioxide hybrid metamaterials

The phase transition property of vanadium dioxide (VO2) makes it an attractive field in temperature-controlled chips. In this paper, a microstructure based on a graphene disk and a ring-shaped VO2 hybrid metamaterial is proposed to achieve switchable dual ultra-broadband perfect absorption in the terahertz region, which is analyzed by the phase transition property of VO2 and the dynamic electrical regulation of graphene. When the graphene disk is not present, the absorption intensity can reach up to 97.07%. When the graphene disk is present and respectively interacts with the VO2 metallic and insulated phases, the results exhibit an ultra-broadband perfect absorption (>90%) from 1.620 THz to 4.533 THz and from 1.506 THz to 3.576 THz, respectively, where the bandwidths are as high as 2.913 THz and 2.070 THz, respectively. Adjusting the Fermi level of graphene and the VO2 conductivity allows the absorption intensity and bandwidth to be effectively controlled, where the fractional bandwidth from 81.46% to 94.69% and a high modulation depth of 95.09% can be achieved. These results suggest that dual ultra-broad perfect absorption can be dynamically switched within a single absorber and has various modulation means, which are expected to be developed in applying multifunctional modulators.

Experimental investigation of natural convection behavior of novel silver-doped Titanium dioxide hybrid nanofluid

Experimental investigation of natural convection behavior of novel silver-doped Titanium dioxide hybrid nanofluid

Polyoxomolybdate-Based Metal-Organic Framework-Derived Cu-Embedded Molybdenum Dioxide Hybrid Nanoparticles as Highly Efficient Electrocatalysts for Al-S Batteries.

High-performance rechargeable aluminum-sulfur batteries (RASB) have great potential for various applications owing to their high theoretical capacity, abundant sulfur resources, and good safety. Nevertheless, the practical application of RASB still faces several challenges, including the polysulfide shuttle phenomenon and low sulfur utilization efficiency. Here, we first developed a synergistic copper heterogeneous metal oxide MoO2 derived from polymolybdate-based metal-organic framework as an efficient catalyst for mitigating polysulfide diffusion. This composite enhances sulfur utilization and electrical conductivity of the cathode. DFT calculations and experimental results reveal the catalyst Cu/MoO2@C not only effectively anchors aluminum polysulfides (AlPSs) to mitigate the shuttle effect, but also significantly promotes the catalytic conversion of AlPSs on the sulfur cathode side during charging and discharging. The unique nanostructure contains abundant electrocatalytic active sites of oxide nanoparticles and Cu clusters, resulting in excellent electrochemical performance. Consequently, the established RASB exhibits an initial capacity of 875 mAh g-1 at 500 mA g-1 and maintains a capacity of 967 mAh g-1 even at a high temperature of 50 °C.

Enhanced visible-light induced photocatalytic activity in core-shell structured graphene/titanium dioxide nanofiber mats

Semiconductor photocatalysts suffer from low photocatalytic quantum efficiency, diminished solar energy utilization, and inadequate photostability, thereby impeding their widespread adoption. Meanwhile, graphene emerges as an ideal substrate material for fabricating high-performance composite photocatalysts owing to its distinctive single-layer sp2-hybridized carbon atom arrangement, substantial specific surface area, exceptional electron conductivity, and pronounced transparency. In this study, a graphene-anatase-rutile core-shell structured nanofiber mat architecture is successfully synthesized by sol-gel-assisted coaxial electrospinning with high-temperature thermal treatment. This innovative architecture effectively narrows the bandgap of TiO2 and synergizes adsorption and catalysis processes to achieve heightened catalytic efficiency and prolonged stability. Photocatalytic assays conducted under visible light irradiation demonstrate the excellent photocatalytic activity and stability of the graphene-titanium dioxide hybrid material during the degradation of phenol. The kinetics and mechanism of the phenol degradation of the nanofiber mat have been explored. Furthermore, the unique mesh-like configuration intrinsic to the nanofiber assembly confers sedimentation and recyclability upon the composite material.

Structural design of CA/SiO2 hybrid nanofiber membranes with semi-interpenetrating structure and switching wettability

The development of a stable structure separation membrane with adaptive switching wettability has positive significance for the expansion of membrane applications, especially in complex processing scenarios. Herein, a kind of core-shell cellulose acetate/silicon dioxide (CA/SiO2) hybrid nanofiber membrane with a semi-interpenetrating structure and switching wettability surface property was prepared via electrospinning process and subsequently in-situ hydrolysis, which integrated a superamphiphilicity SiO2 shell onto the porous CA nanofibers core to form an anchor embedding structure by vacuum forcing the silica precursor into the pores of CA nanofibers. The obtained CA/SiO2 hybrid nanofiber membrane exhibited superamphiphilicity in air with adaptive switching wettability, appearing non-stick to oil underwater or to water underoil, corresponded to superoleophobicity underwater and superhydrophobicity underoil, respectively. The CA/SiO2 hybrid nanofiber membrane with the hydrolysis time of 5 h demonstrated excellent properties. It achieved permeation fluxes of 19771 and 9104 L/m2·h with a separation efficiency exceeding 99.99% for immiscible light/heavy oil/water mixtures when pre-wetted by water and oil and subjected to gravity. Moreover, the semi-interpenetrating structure of SiO2 nanoparticles to CA nanofibers ensured the structural stability of the CA/SiO2 hybrid nanofiber membranes, which endowed it with excellent reusable performance.

Green synthesized clove-treated carbon nanotubes/titanium dioxide hybrid nanofluids for enhancing flat-plate solar collector performance

Green synthesizing carbon-based hybrid nanofluids has the potential to drive innovation in both renewable energy technologies and nanomaterial applications. In this regard, the current experimental work focuses on enhancing the thermal performance of flat-plate solar collectors (FPSCs) using working fluids made of nanocomposite materials via an eco-friendly technique (clove). Conventional methods of synthesizing nanofluids frequently involve using hazardous chemicals, raising concerns about the environment and human health. This experimental work examined the energy efficiency, exergy efficiency, and hydrothermal performance of FPSC using clove-treated carbon nanotubes/titanium dioxide (CT-MWCNTs/TiO2) nanocomposites by the ratio of (60 % to 40 %) dispersed in distilled water (DW). The test conditions were in the following ranges: hybrid nanofluid in different weight concentrations (0.025, 0.05, 0.075, and 0.1 wt%), different flow rates (0.3, 0.6, 0.9, and 1.2 L/min), heat flux intensities (400, 600, 800, and 1000 W/m2) and inlet temperature (30, 35, 40, 45 °C). The experimental results revealed that, the maximum enhancement in the energy efficiency (20.6 %) and exergy efficiency (22.9 %) were achieved at 0.1 wt% and 1.2 L/min, relative to the base fluid. In addition, the solar collector size was reduced by 20.5 % due to using a hybrid nanofluid. To conclude, the hybrid nanofluid outperformed the mono nanofluids regarding overall thermal evaluations. The novel hybrid nanofluids generally showed promising results for managing and conserving energy applications.

Reduced Graphene Oxides Skeleton Hybrid Interface Enables Long Lifespan Zinc Metal Anodes

AbstractWith the ever‐growing demands for the electrical energy storage market, aqueous zinc‐ion batteries (AZIBs) are showing great prospects owing to their good capacity, low cost, and high safety. Nevertheless, they also face significant challenges, particularly in the form of zinc dendrite growth and inadequate stability. Here, a strategy based on reduced graphene oxides‐zirconium dioxide (rGO/ZrO2) hybrid interface to enable long lifespan zinc metal anodes is proposed. Via in situ electrochemical deposition and self‐assembly method, rGO and ZrO2 are deposited on the zinc metal anode successively, and their loading is optimized subsequently. In the functionalized interface, rGO serves as the skeleton and improves electrolyte ion diffusion, while ZrO2 relieves the electric field concentration problem and inhibits dendrite growth. As a result, the Zn@rGO@ZrO2 symmetric cell achieves a highly reversible cycle of 3000 h at 2.0 mA cm−2/1.0 mA h cm−2 and fast reaction kinetics.

Influence of graphene nanoplatelets (GnPs) and titanium dioxide (TiO2) hybrid fillers on the mechanical, thermal, and morphological performance of polypropylene (PP) based hybrid composites

The main objective of the present study was to investigate the influence of graphene nanoplatelets (GnPs), Titanium dioxide (TiO2), and its hybrid filler on the mechanical, thermal, and morphological characteristics of polypropylene (PP) based hybrid composites for structural applications. The PP-based hybrid composites were prepared using a twin-screw extruder for different filler compositions and then molded into tensile specimens with a mini-jet injection molding setup. Tensile, thermal, and morphological analyses were performed to determine the hybrid capability of the PP-based composites. The results showed that the values of tensile modulus and tensile yield strength show significant improvement at about ∼24% and ∼17%, while the values of elongation at break show a slightly decreasing trend for the hybrid composites compared to PP composites. The thermal stability analysis shows that the higher the hybrid filler content, the higher the temperature. Further, the SEM micrographs for the hybrid fillers show good dispersion onto the PP matrix, which may increase the interfacial adhesion between PP and fillers, thus enhancing the mechanical and thermal properties of PP-based hybrid composites.

Corrigendum to “Influence of graphene nanoplatelets (GnPs) and titanium dioxide (TiO2) hybrid fillers on the mechanical, thermal, and morphological performance of polypropylene (PP) based hybrid composites”

Corrigendum to “Influence of graphene nanoplatelets (GnPs) and titanium dioxide (TiO₂) hybrid fillers on the mechanical, thermal, and morphological performance of polypropylene (PP) based hybrid composites”

Ternary cobalt ferrite (CoFeO4)-silver (Ag)-titanium dioxide (TiO2) hybrid nanofluid hydromagnetic nonlinear radiative-convective flow from a rotating disk with viscous dissipation, non-Darcy and non-Fourier effects: Swirl coating simulation

Magnetic nanoparticles are increasingly being deployed in smart coating systems due to their exceptional functionalities and abilities to be tuned for specific environmental conditions. Inspired by the emergence of tri-hybrid magnetic nanofluids which utilize three distinct nanoparticles in a single base fluid coating, the present article examines analytically and computationally the swirl coating of magnetic ternary hybrid nanofluid from a rotating disk, as a simulation of spin coating deposition processes in materials manufacturing. Owing to high temperature fabrication conditions, thermal radiative heat transfer is also considered and a Rossleand flux model deployed. -- hybrid nanoparticles are considered with Ethylene Glycol-Water () base fluid. A filtration medium is also featured (porous medium) adjacent to the disk and the Darcy-Forchheimer model is deployed to simulate both bulk matrix porous drag encountered at lower Reynolds numbers and inertial quadratic drag generated at higher Reynolds numbers. Thermal relaxation of the coating nanofluid is additionally addressed and a non-Fourier Cattaneo-Christov model is therefore implemented in the heat conservation equation. Viscous dissipation is also included in the model. The governing conservation equations for mass, momenta (radial, tangential and axial) and energy with prescribed boundary conditions are rendered into coupled nonlinear ordinary differential boundary layer equations via suitable scaling variables and the Von Karman transformations. The derived reduced boundary value problem is then solved with a Runge-Kutta numerical scheme and shooting scheme in MATLAB. Validation of solutions is included with previous studies. Radial and azimuthal velocities, temperature, radial skin-friction, azimuthal skin friction and local Nusselt number are computed for a range of selected parameters. A comparative assessment of mono nanofluid Hybrid - nanofluid and tri-Hybrid -- nanofluid is conducted. This combination of hybrid nanoparticles has never been examined previously in the literature and constitutes the significant novelty of the present work. Both radial and tangential velocity are depleted with increasing applied magnetic field whereas temperature and thermal boundary layer thickness are increased.

Effect of discrete heating on the key parameters and entropy generation in a corrugated enclosure filled with hybrid nanofluid

This research work aims to study the effect of discrete heating on natural convective heat transfer, fluid flow, and entropy generation within a corrugated enclosure filled with water-based molybdenum disulfide (MoS2)–silicon dioxide (SiO2) hybrid nanofluid. In the study, various heights of the discrete heaters in terms of aspect ratios ( AR = 0.2 , 0.4 , 0.6 , 0.8 ) are considered for various Rayleigh numbers ( Ra = 10 3 − 10 6 ) with varying nanoparticle volume fractions ( ϕ = 0 % − 4 % ). Stream function-vorticity formulations of two-dimensional (2D) Navier-Stokes equations and energy equation are used as the governing equations, and a higher-order compact (HOC) finite difference scheme is employed to discretize those equations. The results obtained from the current developed code are first validated with the existing numerical and experimental data. Finally, the present computed results are studied, both qualitatively and quantitatively, in terms of streamlines, isotherms, entropy generations, average Nusselt numbers, and Bejan numbers. At Ra = 10 6 and the aspect ratio of heater length AR = 0.2 , a different and interesting flow and heat transfer phenomenon is observed. The results show that an increase in the aspect ratio of heater length from 0.2 to 0.8 decreases the average Nusselt number and total entropy generation by 57.49% and 13.76%, respectively, for Ra = 10 6 and ϕ = 4 % . In addition, the effect of nanoparticle concentration on total entropy generation increases up to 73.40% when the aspect ratio of heater length increases to 0.8.

Structure, wettability and photocatalytic activity of graphene doped multi-walled carbon nanotubes/titanium dioxide hybrid coatings

This paper presents the findings of the structure, wettability and photocatalytic activity of 32 wt % graphene-doped multi-walled carbon nanotubes (G-MWCNTs) / titanium dioxide (TiO2) hybrid coatings under three different ratios. The hybrid coatings of G-MWCNTs/TiO2 were compared with the pure (undoped) TiO2 coating. Pure TiO2 and G-MWCNTs/TiO2 hybrid coatings were prepared by sol-gel method and deposited on soda-lime-silica (SLS) glass substrates using a dip coater. The samples were heat-treated in the air at 500 °C for 1 h. The nano-sized G and MWCNTs used as dopants in the resulting hybrid solution were mixed without agglomeration by the sonication method based on the DLVO theory, without any surfactants. To prevent the migration of Na+ ions contained in the structure of SLS glass to TiO2-based coatings, a SiO2-based sol-gel coating was first deposited on the SLS glass surface using the dip coating method. This was done before applying the pure TiO2 coating and G-MWCNTs/TiO2 hybrid coating process. All samples were crystallized in the anatase form and exhibited superhydrophilic behavior. The G-MWCNTs/TiO2 hybrid coated samples' photoactivity was determined using the ISO 10678 MB degradation standard. According to the ISO 10678:2010 MB degradation standard, G-MWCNTs/TiO2 hybrid coated samples exhibited photonic efficiency.

Investigation of mechanical properties of glass, jute and coir fibers composites with and without silicon dioxide (SiO2) filler

The current engineering market is choosing composite materials over traditional materials inspired by the superior properties exhibited by composite materials, they are made up of a combination of materials with distant chemical and physical properties. The utilization of glass fiber composites is very extensive in the fields of aircraft and automobile industries most glass fibers are silica based and contain a host of other oxides of sodium iron, calcium, etc. natural fiber reinforced composites are getting progressively paramount because of low-cost and high specific characteristics fiber. The strength of the weight fraction of these composites is huge and vast. The present work aims at finding out the effects on the mechanical properties of composites due to the addition of silicon dioxide hybrid filler. The tensile and flexural tests are carried out on a universal testing machine (UTE-10), an impact test is done on the impact testing machine, and results were obtained.

Biopolymer assisted synthesis of metal–silica hybrid nanoflowers as a medium for the photocatalytic degradation of dye pollutants

This report presents an ecofriendly synthesis and characterization of biopolymer (sodium alginate)-capped silver nanoparticle-silicon dioxide (Ag-SiO2) hybrid nanoflowers and their efficiency for the plasmon-mediated dye degradation of methylene blue. The reducing and capping agents for the initial silver nanoparticles (AgNPs) synthesis were glucose and sodium alginate, respectively. The mesoporous silica nanostructures were introduced using two-step hydrolysis followed by a polycondensation process. Detailed structural and morphological characterizations of the as-prepared hybrid nanostructures were done using various techniques. The results revealed the formation of nanoflower-like hybrid alginate-capped Ag-SiO2 nanostructures with a size range of approximately 523 ± 56 nm. The BET surface area analysis showed that the hybrid nanostructure has a surface area of 15.6 m2/g together with a pore diameter of 18.2 nm. The hybrid Ag-SiO2 nanoflowers showed excellent catalytic properties for the visible light photodegradation of methylene blue dye after 1 min exposure compared to silver nanoparticles at the same condition. The synergistic effect of SiO2 and Ag nanoparticles improved the catalytic property of the hybrid nanostructure. This study demonstrated a simple and effective model for the efficiency of designed hybrid nanostructures for degradation of industrial dyes.

Gold Nanorod/Titanium Dioxide Hybrid Nanoparticles for Plasmon-Enhanced Near-Infrared Photoproduction of Hydroxyl Radicals and Photodynamic Therapy.

Gold nanoparticles, such as nanorods (AuNRs), present exceptionally high absorption cross sections that can be tuned to the near-infrared (NIR), the optimal window for light penetration in biological tissues. This makes them valuable photosensitizers for the treatment of cancer using photothermal therapy, where absorbed light energy is converted into heat. In addition, there is a strong interest in using hot electron carriers generated in AuNRs by NIR irradiation to produce cytotoxic radical oxygen species in order to enhance the efficiency of the phototherapy. Here, we show that hybrid nanoparticles composed of AuNRs with TiO2 deposited at their extremities are efficient sensitizers to produce hydroxyl radical species under NIR irradiation. We attribute this phenomenon to the transfer of hot electrons generated from the plasmon excitation in AuNR to the TiO2 tips, followed by reduction of dioxygen. We then functionalize these hybrid AuNR/TiO2 nanoparticles with block poly(ethylene glycol)-phosphonate polymer ligands to stabilize them in a physiological medium. We finally demonstrate that the photodynamic effect induces cell death upon irradiation with a greater efficiency than the photothermal effect alone.

Optimum design of bivariate operation strategy for a supercritical/ transcritical CO2 hybrid waste heat recovery system driven by gas turbine exhaust

Gas turbines are always operated under part-load conditions to participate in the frequency regulation of power grids; therefore, the exhaust gas has fluctuating temperature and mass flow rate parameters. For better utilization of the waste heat in gas turbine exhaust under part-load conditions, a supercritical/transcritical carbon dioxide (CO2) hybrid waste heat recovery system with different operation strategies was studied. The turbine inlet pressure and mass flow rate were considered as the dominant factors affecting the system part-load performance, which formed a bivariate operation strategy. A solution procedure was proposed to optimize the bivariate operation strategy for a hybrid waste heat recovery system. The results indicate that the mass flow rate of the transcritical CO2 cycle has a greater effect on its net power than the turbine inlet pressure whereas these two regulation variables should be controlled cooperatively. The net power of the hybrid waste heat recovery system increased with an increase in the inlet valve opening of the supercritical CO2 turbine under a specific gas turbine load. Generally, the optimal bivariate operation strategy has the advantage of enhancing the part-load performance of a hybrid waste heat recovery system driven by gas turbine exhaust.