Graphene TiO2 Research Articles

Biomass-Derived Cellulose Acetate Membranes Modified with TiO2/Graphene Oxide for Oil-In-Water Emulsion Treatment.

Considering the environmental impact and health risks caused by oily wastewater in the petrochemical industry, it is crucial to develop more efficient separation techniques than traditional methods, such as membrane separation, for treating stable emulsions enriched with natural surfactants. This study investigated the preparation of dense cellulose acetate membranes from a low-cost biomass precursor (Luffa cylindrica) and their modification with graphene oxide (GO) and TiO2 nanoparticles, aiming to obtain a polymeric nanocomposite with good flux characteristics and selectivity for the treatment of oil/water emulsions. The materials obtained were characterized using techniques such as X-ray diffraction, nuclear magnetic resonance spectroscopy, infrared absorption spectroscopy, along with optical and scanning electron microscopy, among others. The membranes were prepared by the casting technique and modified with the above-mentioned nanostructured materials. Flux analyses with petroleum emulsion revealed that membranes modified with GO and TiO2 nanoparticles showed significant improvements in antifouling resistance compared to unmodified membranes. These enhanced properties highlight the potential of modified cellulose acetate membranes for application in industrial wastewater treatment.

Assembled Wood-Polyester Fabric-Hydrogel Janus Evaporator for Sustainable Seawater Desalination.

Solar-driven interfacial evaporation technology is a novel and efficient desalination process that helps alleviate the global shortage of freshwater resources. We developed a Janus evaporator assembled from cotton hydrogel, hydrophilic polyester fabric (PF), and Hydrophobic Wood (PW). By doping graphene oxide and TiO2 as light-absorbing materials within the hydrogel, we achieved a high absorptivity of over 90% across the entire solar spectrum. The hydrophilically modified PF, combined with the PW substrate, provided robust water transport and reduced thermal losses. Subsequent optical path simulations using TracePro74 software verified that the sawtooth light-trapping design of the wood substrate increased multiple light reflections and absorption (compared to a flat structure), enhancing light absorption capabilities. The sawtooth interface also enlarged the evaporation area, further boosting evaporation performance. The cleverly designed evaporator exhibited an evaporation rate of 1.722 kg m-2 h-1 and an efficiency of 83.1% under 1 sun irradiation. Additionally, after applying polydimethylsiloxane to the single surface of the photothermal hydrogel for low surface energy treatment, the resulting Janus structure demonstrated asymmetric wettability that prevented salt ions from accumulating on the irradiated interface. After 8 h of continuous evaporation in saline water (10 wt %), only slight salt crystallization occurred at the edges. The evaporator maintained long-term stability during a 15 day cyclic test, and the produced freshwater fully met the relevant drinking water standards. The components of the evaporator are characterized by simple fabrication, low cost, and eco-friendliness, offering significant application potential in the global context of energy conservation and emission reduction initiatives.

Characterization of graphene–TiO2-deposited semi-organic solar cell

High energy supply is critical, particularly in developing countries, to maintain lifestyles as the world's population and technological-economic metropolis grow. Solar photovoltaic cells have been used as an alternative to generate renewable, sustainable, and green energy for the past two decades. In general, the materials employed in the photoanode part are critical to manufacturing high-efficiency solar cells with 14–18% efficiency. A simple and successful method has been discovered for creating a film composed of graphene sheets and 99.8% pure anatase titanium oxide (TiO2) nanoparticles. After sensitization, the films were tested as photoelectrodes for dye-sensitized solar cells. The experimental results show that using an optimized graphene material considerably improves the power conversion efficiency of the cells, resulting in a 45% increase in short-circuit current density ( JSC). This study uses capsician as a bonding agent to enhance the current density of a graphene–TiO2 based semi-organic solar cell. The mechanical and electrical properties of the cell are investigated using a scanning electron microscope, energy dispersive X-ray, and Corescan.

Facile synthesis of RGO/TiO2 heterojunction on SiNWs on Si chip for near infrared detector

Here, a ternary nanostructure-based heterojunction was developed for the detection of infrared (IR) radiation in near wavelength range. During materials synthesis process, silicon nanowires (SiNWs) were developed using metal assisted chemical etching (MACE) technique whereas reduced graphene oxide (RGO) sheets and TiO2 nanoparticles were synthesized by chemical vapour deposition (CVD) and solvothermal method, respectively. Thereafter, RGO/TiO2 nanostructure was deposited over SiNWs to form a heterojunction. To analyse the stoichiometry, morphology, and internal structure, various characterization techniques were performed such as scanning electron microscope (SEM), transmission electron microscope (TEM), Energy dispersive spectrometer (EDS), X-Ray Diffractometer (XRD), UV–Vis spectrophotometer and X-Ray Photoelectron Spectrometer (XPS). The RGO/TiO2@SiNWs nanostructure-based heterojunction was used for the detection of near IR radiation where the responsivity (R) was found to be 17.22 × 10−3 A/W and detectivity (D) was measured to be 0.23 × 1011 Jones with response time < 1 s and recovery time < 3 s. These results were found comparatively better than pristine RGO@Si and RGO@SiNWs nanostructure-based sensors used for the near IR detection under same conditions. The photocurrent response was also recorded with 5 ON/OFF cycles which depicted a good reproducibility of the prepared detector. Hence, the SiNWs on Si chip based highly sensitive and selective photodetector can be used to set a new milestone for various near IR applications.

Thermo-mechanical behaviours investigation of Nano-Sized Al2O3, TiO2, and Graphene Nanoplatelet Reinforced Epoxy Composites

Composite materials find extensive applications in various industries, thanks to their remarkable properties. These sectors include energy, maritime, motor sports, aviation, space and defense. The materials commonly used in these sectors are fiber reinforced plastic (FRP) composite materials. Epoxy materials are commonly used as matrix in the production of FRP materials. This study delves into the enhancement of epoxy-based nanocomposites by using graphene nanoplatelets (GNP-5nm), TiO2 (13nm), and Al2O3 (8nm) nanoparticles. These nanoparticles were added at varying mass ratios into a commercial epoxy to investigate their effects on some chemical, thermal and mechanical properties. Meticulous mixing methodologies were used to reduce clumping effects and ensure even distribution during the process. The curing process was carried out in a PLC (Programmable Logic Controller) controlled hot air oven under isothermal conditions under the influence of 100 °C for 30 minutes. Tensile strength, elongation at break, toughness, resilience modulus, elasticity modulus, hardness, FTIR analysis and thermal conductivity properties were characterized to assess the nanoparticle influence on the epoxy matrix. The results showed that there were remarkable improvements in mechanical properties with nanoparticle reinforcement. Especially, 1.25% Al2O3 inclusion exhibited a substantial increase of 140.32% in tensile strength and a 7% rise in shore D hardness compared to pure epoxy. This enhancement was attributed to enhanced O-H bonding between 'O' atoms in Al2O3 nanoparticles and epoxy polymer chains, enhancing matrix-filler interactions. Additionally, the effect of 1.0% TiO2 led to plasticity, displaying a 32% rise in elongation at break, signifying improved deformation energy absorption compared to neat epoxy. In thermal conductivity measurements, the highest thermal conductivity was observed in the sample with 1.25% GNP added and it increased by 123.5% compared to neat epoxy. In TiO2 and Al2O3 added samples, an increase of 69% and 47%, respectively, was observed at 1.25% additive rates compared to neat epoxy. According to the results, thanks to the nanoparticle reinforcement added into the epoxy matrix, composite structures can be given new and superior properties specific to the applications.

Development of Neem Oil Ester Modified With Reduced Graphene Oxide and TiO₂ for Distribution Transformers

Development of Neem Oil Ester Modified With Reduced Graphene Oxide and TiO₂ for Distribution Transformers

Titania/graphene nanocomposites from scalable gas-phase synthesis for high-capacity and high-stability sodium-ion battery anodes

In sodium-ion batteries (SIBs), TiO2 or sodium titanates are discussed as cost-effective anode material. The use of ultrafine TiO2 particles overcomes the effect of intrinsically low electronic and ionic conductivity that otherwise limits the electrochemical performance and thus its Na-ion storage capacity. Especially, TiO2 nanoparticles integrated in a highly conductive, large surface-area, and stable graphene matrix can achieve an exceptional electrochemical rate performance, durability, and increase in capacity. We report the direct and scalable gas-phase synthesis of TiO2 and graphene and their subsequent self-assembly to produce TiO2/graphene nanocomposites (TiO2/Gr). Transmission electron microscopy shows that the TiO2 nanoparticles are uniformly distributed on the surface of the graphene nanosheets. TiO2/Gr nanocomposites with graphene loadings of 20 and 30 wt% were tested as anode in SIBs. With the outstanding electronic conductivity enhancement and a synergistic Na-ion storage effect at the interface of TiO2 nanoparticles and graphene, nanocomposites with 30 wt% graphene exhibited particularly good electrochemical performance with a reversible capacity of 281 mAh g−1 at 0.1 C, compared to pristine TiO2 nanoparticles (155 mAh g−1). Moreover, the composite showed excellent high-rate performance of 158 mAh g−1 at 20 C and a reversible capacity of 154 mAh g−1 after 500 cycles at 10 C. Cyclic voltammetry showed that the Na-ion storage is dominated by surface and TiO2/Gr interface processes rather than slow, diffusion-controlled intercalation, explaining its outstanding rate performance. The synthesis route of these high-performing nanocomposites provides a highly promising strategy for the scalable production of advanced nanomaterials for SIBs.

Switchable visible and near-infrared light bifocal lens based on hybrid graphene-metasurface structures

We propose a wideband visible (VIS) and near infrared (NIR) light reflective flat lens with switching capability base on hybrid graphene-metasurface structure. This tunable flat lens structure consists of a slotted gold reflector substrate, a graphene monolayer and TiO2 nanofins that provide excellent focusing performance and tunability in the VIS and NIR range. In order to achieve the switching feature, a bi-functional device capable of switching reflection/absorption modes is required. To this end, the gold substrate with two cross slots has been used to create absorption properties and a graphene layer has been used to change the intensity of absorption and reflection. The switching property for incident light with circular polarization arises from uniformly changing the chemical potential of the graphene layer. By setting the chemical potential of graphene, μc, equal to 1.1 eV, we obtained the reflection property. The reflection mode exhibits a broadband (715–800 nm) optical response with high polarization conversion efficiency (more than 70 %). On the other hand, by choosing μc = 0.75 eV, the absorption feature is created at the wavelength of 700–780 nm. The reflected light can be focused on an arbitrary position above the structure by rotating the TiO2 nanofins with the help of Pancharatnam-Berry (PB) phase theory. In addition to obtaining the single and dual focus tunable flat lenses, we have also presented a multifunction configuration that can switch between different modes, such as non-focus, single and dual focus modes. Such switchable flat lenses can have various applications in imaging and sensing systems.

Exploring the use of graphene lubricant and TiO2 nanolubricants in micro deep drawing of stainless steel SUS301

This study investigates the effects of different lubrication conditions on drawing force and microcup formation during micro deep drawing (MDD). Results show that graphene lubricant, in combination with TiO2 nanolubricants, has the potential to reduce friction during MDD. The peak drawing force was reduced by 15.39% when both lubricants were used together, while the use of TiO2 nanolubricant and 10.0 mg/ml graphene lubricant reduced it by 6.03% and 14.52%, respectively. The study also reveals that lubricants reduce wrinkling during the formation of microcups by minimising energy consumption during the primary formation. However, the combination of TiO2 nanolubricant and graphene lubricant can cause inhomogeneous formation on the upper part of the blank, leading to more apparent wrinkling. Overall, the study highlights the potential of TiO2 nanolubricant and graphene lubricant in reducing friction and improving microcup formation during MDD.

Fabrication of amorphous TiO2 hydrogen channels and graphene wrappers to enhance the hydrogen storage properties of MgH2 with extremely high cycle stability

Amorphous TiO2 hydrogen channels and graphene wrappers to enhance the hydrogen storage performance.

A novel paper-based electrochemical device modified with Ni-doped TiO2 nanocrystals-decorated graphene oxide for ascorbic acid detection

This study presents the development of a novel paper-based electrochemical device modified with pure and nickel-doped TiO2 nanocrystals and graphene oxide to enhance its ability to detect ascorbic acid (AA). The use of nanomaterials in the fabrication of the sensor provides a high surface area-to-volume ratio, leading to an increase in the sensitivity and selectivity of the device. The nanomaterials were synthesized, and a combination with the best properties was selected for detecting AA. The morphological, structural, and electrical properties of the nanomaterials in the paper device were investigated using scanning electron microscopy (SEM), Raman spectroscopy (Raman), and cyclic voltammetry (CV), respectively. The sensor's performance was evaluated through various experiments, including cyclic voltammetry, to measure its sensitivity and selectivity in detecting AA. The results indicate that adding Ni-doped TiO2 nanocrystals improves the sensor's sensitivity while incorporating graphene oxide enhances its selectivity. Furthermore, the sensor's performance was compared to that of other commonly used sensors, and it was found to be highly sensitive and selective. Therefore, this paper-based electrochemical sensor, modified with nanomaterials, shows great potential for detecting AA and other applications, such as environmental monitoring and medical diagnostics, due to its high sensitivity and selectivity, low cost, and ease of use.

Enhanced Performance of Micro Deep Drawing through the Application of TiO2 Nanolubricant and Graphene Lubricants on SUS 301 Stainless Steel Foil

In recent years, the quest for effective lubrication in micro deep drawing (MDD) has seen promising advancements. In this study, the influence of TiO2 nanolubricants and graphene lubricants on the performance of 301 stainless steel foil in MDD is examined. The MDD undergoes an extensive evaluation of various lubrication conditions, including dry, TiO2 nanolubricant, graphene lubricant at concentrations of 2.5 mg/mL, 5.0 mg/mL, and 10.0 mg/mL, as well as combined applications of TiO2 and graphene lubricants. Utilising a 5.0 mg/mL graphene lubricant together with TiO2 nanolubricants led to a significant reduction in drawing force, highlighting the synergistic efficacy of this combined lubricant. A pronounced enhancement in the consistency of the produced microcups was also attained. These results emphasise the promise of TiO2 nanolubricant and graphene lubricants in optimising the MDD process.

Exploring the bioactivity of reduced graphene oxide and TiO2 nanocomposite for the regenerative medicinal applications

Millions of people globally suffer from issues related to chronic wounds due to infection, burn, obesity, and diabetes. Nanocomposite with antibacterial and anti-inflammatory properties is a promising material to promote wound healing. This investigation primarily aims to synthesize reduced graphene oxide and titanium dioxide (rGO@TiO2) nanocomposite for wound healing applications. The rGO@TiO2 nanocomposite was synthesized by the one-step hydrothermal technique, and the physicochemical characterization of synthesized nanocomposite was performed by X-ray diffraction, Fourier transforms infrared spectroscopy, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy, and dynamic light scattering. Further, the nanocomposite antibacterial, cytotoxicity, and wound-healing properties were analyzed by disc diffusion method, MTT assay, and in vitro scratch assay, respectively. Based on the TEM images, the average particle size of TiO2 nanoparticles was around 9.26 ± 1.83 nm. The characteristics peak of Ti–O–Ti bonds was observed between 500 and 850 cm−1 in the Fourier transforms infrared spectrum. The Raman spectrum of graphene oxide (GO) was obtained for bands D and G at 1354 cm−1 and at 1593 cm−1, respectively. This GO peak intensity was reduced in rGO, revealing the oxygen functional group reduction. Moreover, the rGO@TiO2 nanocomposite exhibited dose-dependent antibacterial properties against the positive and negative bacterium. The cytotoxicity for 5–100 µg/mL of rGO@TiO2 nanocomposite was above the half-maximal inhibitory concentration value. The in vitro scratch assay for rGO@TiO2 indicates that the nanocomposite promotes cell proliferation and migration. The nanocomposite recovered the wound within 48 h. The rGO@TiO2 nanocomposite shows potential materials for wound healing applications.

Influence of Radical Scavenger on Radiation Synthesis of Graphene Oxide/TiO2 Nanotubes/Ag Nanoparticles Nanocomposites and Their Dye Photodegradation Efficiency

Aqueous solutions of graphene oxide (GO), TiO2 nanotubes (TNTs), and silver nanoparticles (AgNPs) were synthesized through a facile, single-step radiolytic method at room temperature and ambient pressure. The resulting material, referred to as GO-TNTs-AgNPs (GTA), was investigated for its potential application in the photodegradation of Rhodamine-B (RhB) dye. This synthesis process relies on the interaction of high-energy gamma rays from a 60Co source with the water in the aqueous solutions. The main objective of this study was to evaluate the effect of irradiation dose and the presence of polyethylene glycol (PEG) solution on the combination within the nanocomposite materials. The inefficiency of GTA synthesis experimentally was in agreement with the hydroxyl radical (HO•) scavenger. Then, the irradiated materials were structurally characterized using various spectroscopic methods (Fourier transform infrared (FTIR), X-ray diffraction (XRD), Raman spectroscopy, and ultraviolet-visible absorption (UV–Vis)). Scanning electron microscopy (SEM) studies reveal the variable morphology of nanocomposites. GTA samples in water exhibited significantly higher degradation efficiency on Rhodamine B dye under natural sunlight irradiation conditions.

Synthesis of functionally graded aluminium metal matrix composites - a mini review

Functionally graded materials (FGMs) are materials with property gradients along a particular dimension. These are novel and advanced materials that are becoming excellent replacements for composites. Among the FGMs, functionally graded Aluminum metal matrix composites (FG AMMCs) are receiving tremendous attention as they possess versatile properties compared to their counterparts. Out of various synthesizing techniques, the Powder metallurgy (PM) route is the cheapest and easier method of fabricating functionally graded composites (FGCs). This review provides information about the Functionally graded Aluminium metal matrix composites and their synthesis through the PM route. The review analyses important properties including density, hardness, tensile and compressive strength. A study of the microstructure through Scanning Electron Microscopy (SEM) of the synthesized FGMs is presented. The PM route could be conveniently exploited for large-scale production of FG AMMCs. There is scope for the characterization of FG AMMCs reinforced with B4C, TiO2, TiB2, TiC, CNT, and Few layered Graphene (FLG) as only a few studies are reported in the literature. The variation in mechanical and tribological properties of the FGMs could be investigated by varying the processing parameters of the ball milling, compacting, and sintering conditions.

Multi-contact prismatic spiky block titanium dioxide–graphene covalent composites for formaldehyde degradation

In this study, in situ solvothermal growth was carried out to fabricate multi-contact prismatic spiky block TiO2–graphene covalent composites (PTG) with unique morphologies. Prismatic conical TiO2 projections were uniformly formed on graphene sheets, yielding block PTG with Ti–C and Ti–O–C covalent bonds. The crystal structure and morphological properties of PTG were characterized, and its photocatalytic performance was evaluated. The covalent doping of graphene sheets resulted in the superior gaseous formaldehyde degradation activity of PTG compared to that of prickly spherical TiO2, with a degradation rate of 80.1% under visible light after 120 min. Electron paramagnetic resonance spectroscopy revealed that PTG displayed a sustained radical response and maintained high catalytic activity after five cycles of formaldehyde degradation. The reliable cycling stability and visible-light-induced photocatalytic activity of PTG suggest its potential for application in the field of hazardous gas degradation.

Crystalline F-doped titanium dioxide nanoparticles decorated with graphene quantum dots for improving the photodegradation of water pollutants

Carbon dots are emerging photoactive materials with high chemical stability, aqueous solubility, abundant surface functional groups and low-cost production. Their great advantages, incorporated into the high photocatalytic activity of the TiO2, result in hybrid systems that overcome some of the photocatalytic drawbacks associated with TiO2. In this work, a facile synthesis of hybrids of F-doped TiO2 and N-doped graphene quantum dots (F-TiO2@N-GQDs) is reported. These systems have demonstrated efficient photocatalytic properties in light-driven pollutant reduction from water. Therefore, using a simple and low-cost synthesis method, the N-GQDs act as electron reservoirs improving the pairs e--h+ lifetime in TiO2 by decreasing charge recombination, increasing their photocatalytic capacity. The photocatalysts showed very effective degradations of different contaminants such as methylene blue (90% degradation) ciprofloxacin (62% degradation) and naproxen (60% degradation) in short periods of up to 15 min and 4-chlorophenol (59% degradation) in 30 min using UV light (300 W).

Defective graphene decorated with TiO2 nanoparticles as negative electrode in Li-ion batteries

In this work, the performance of novel negative electrodes for Li-ion batteries based on defective graphene synthesized via a scalable thermal exfoliation of graphite oxide and decorated with TiO2 nanoparticles is investigated. Titania polymorphs are interesting as battery electrode materials, owing to their high cycle stability, safety, abundance and negligible solid electrolyte interphase formation and volume changes upon cycling. Defective graphene, on the other hand, can embed TiO2 nanoparticles, forming a conductive hybrid nanocomposite anode material for Li-ion batteries, with improved Li-ion and electron transport, optimising power density. Here we propose two different synthetic approaches for the decoration of graphene with TiO2 nanoparticles: I) a novel chemical route where TiO2 nanoparticles, mainly anatase, were grown on graphene in hydrothermal mild conditions and II) a physical solid-state approach where hydrothermal TiO2 nanoparticles and graphene were mixed together via high energy ball-milling. The synthesized materials were analysed via powder X-ray diffraction, micro-Raman spectroscopy and HR-TEM, while the electrodes were electrochemically tested. Operando synchrotron diffraction was conducted on half-cell to investigate phase transitions in the electrode materials. Even in presence of small amount of graphene, significant improvement in capacity, reversibility, and high-rate capability were observed. In particular, the sample obtained through the addition of 1 wt% of graphene displayed a reversible capacity of more than 180 mA h/g after prolonged and wearing cycling. This result outperforms by 327 % the reversible capacity of pure TiO2 electrode.

CuO decorated graphene TiO2 derived MIL-125 nanocomposite with enhanced photo-response as a highly efficient indirect sunlight driven photocatalyst

Advanced Oxidation Processes (AOPs) are utilized to remove a large range of pollution in water by heterogeneous photocatalysis with production of electron-hole pairs by light. Herein, we showed the preparation of GO/MIL-125 by a simple solvothermal method and then the addition CuO by a simple wet impregnation method. MIL-125 and their derived have attracted considerable attraction due to high earth’s crust abundance, low toxicity, unique photo redox property and photocatalytic application. The photocatalyst, 5CuO/10GO/MIl-125 which was calcined at 600 ◦C (CuTG-600), with a bandgap of 2.82 eV, was utilized to degrade Rhodamine B (RhB) dye which is oxidized to CO2 and H2O. The characterization of different samples was investigated using FT-IR, XRD, XPS, SEM, EDX mapping, UV–vis spectroscopy, Linear sweep voltammetry, photocurrent response, electrochemical impedance spectroscopy (EIS) and Mott-Schottky plots. The combination of GO and CuO increases the degradation activity of RhB dye under irradiation of visible light (λ = 380–780), (blue LED lamp (λ = 450 nm) and red LED lamp (λ = 610 nm)) and the higher results were showed by 5CuTG-600. Photodegradation kinetics were explained by various parameters such as calcination, catalyst type, pH, dye concentration, catalyst dose, different lamps with different wavelengths, different scavengers and reusability. Furthermore, The Photoelectrochemical test results were noticed that the activity of 5CuTG-600 is higher than that of TG-600 and T-600 due to higher donor concentration (ND), and lower recombination process of the charge carrier. Finally, we obtain 5CuTG-600 which acts as an important photocatalyst and is used in environmental and electrochemical applications.

Preparation and characterization of Al8011 TiO2 and nano Graphene hybrid composite mechanical and wear behavior

Aluminum Metal Matrix Composite (AMMC) materials are advantageous in a wide range of engineering applications, most notably due to their lightweight strength, among other factors. The present research focuses on determining the mechanical and wear behavior of Aluminum 8011 (Al8011) reinforced with (30 µm particle size) Graphite (Gr) by 3% by weight fraction and titanium oxide (TiO2) 5%, 10% and 15% weight. Stir casting was chosen as the cheapest approach in this investigation because it was readily available and cost-effective. Distinct samples of the newly developed composites were used in conjunction with a control sample of the aluminum alloy base material. Al8011 reinforced with (Gr) and TiO2 is being investigated in order to better understand how these materials interact with one another when heat treated and without treatment. With increasing TiO2 and Gr content, the hardness improved as well as the hardness up to specific limitations; the microstructure shows the compounds distribution uniformity for Al8011 with 10% TiO2 and 2% wt Gr. The hardness also improved with the same compositions, according to the test findings (10% TiO2 and it was identified that the heat treatment created a strong bond between the compound reinforcement. The wear resistance also increaseswith the hardness.