GO TiO2 Research Articles

Effect of Yttrium doping on enhancing the photocatalytic performance of TiO2/GO nanocomposite

Pure and Yttrium doped Titania/Graphene oxide (YTGO) nanocomposites were synthesized by hydrothermal method. XRD analysis confirmed the crystal structure and anatase phase of TiO2 nanoparticles. The anatase phase of TiO2 has been retained in the composite as confirmed from the XRD pattern. SEM and TEM images revealed that the spherical TiO2 nanoparticles are embedded into sheet like structures of GO. The size of the spherical nanoparticles in the composites is relatively smaller than that of pure sample due to anchoring on the GO sheets. The photocatalytic performance of TiO2 has significantly increased in the Y-doped TiO2 with GO compared to pure TiO2 and TiO2/GO (TGO). Moreover, 0.7 % Y-doped TiO2/GO nanocomposite exhibited superior photocatalytic performance with overall efficiency of 97 % compared to other samples. The 0.7 % Y-doped TiO2/GO nanocomposite shows higher rate constant and shorter half life time compared to other samples. The enhancement of photocatalytic activity of YTGO composites attributed to the combination of increased absorption due to the absorption edge shift and effective separation of photo generated carriers.

A New Synthesis Method and Characterization of Graphene Oxide Nanocomposites for the Leather Tanning Process

Environmental pollution caused by wastes generated from chrome tan is a major concern nowadays. This study aimed to develop an eco-friendly alternative tanning agent using graphene oxide (GO) based nanocomposite materials. GO was synthesized by a new approach with modification of the Hummers method. Two types of GO-based nanocomposites, GO-TiO2 (GT) and GO-TiO2-PEG (GTP) were prepared by adding TiO2 nanoparticles and polyethylene glycol (PEG) as surface modifiers. They were successfully applied to leather tanning processes at different concentrations (2%, 4%, and 6%). Both synthesized GO, GO-nanocomposites, and the resulting tanned leathers were characterized by Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), and Fourier-transform Infrared Spectroscopy (FT-IR). Different physico-mechanical properties of leathers tanned with nanocomposites were evaluated and the results were compared with chrome-tanned leathers. The tensile strength of chrome-tanned leather was 223 (kg/cm) whereas the maximum tensile strength was found at 228 (kg/cm) and 233 (kg/cm) in 6% GO-TiO2 and GO-TiO2-PEG tanned leathers respectively. The environmental pollution impact of the effluents generated by the new tanning process was assessed. The COD of effluents generated from chrome tanning was 4800 ppm which was significantly reduced to 2400-1440 ppm and 2880-1920 ppm when GO-TiO2 (GT) and GO-TiO2-PEG (GTP) were applied in leather tanning respectively. The TDS and BOD were found at 183.8 and 200 ppm in conventional chrome-tanned wastewater which were significantly reduced to the range of 47.5-18.3 and 100-50 ppm respectively in liquid wastes obtained from the GO-composite tanning process. The maximum reduction of COD, BOD, TDS, and TSS in leather waste liquid was found with the application of 2% GO-nanocomposites in tanning. The results revealed that leathers tanned with nanocomposites possess characteristic properties which were very similar to those observed in chrome-tanned leathers whereas the new tanning agents drastically reduced the intensity of pollutants in leather effluents. The application of new nanocomposites in the leather tanning process is an innovative effort. This new nanocomposite-tanning method showed minimal consequences regarding environmental pollution with the generation of less toxic effluents from the respective tanning process.

Molecular characterization and transcriptional response to TiO2–GO nanomaterial exposure of two molt-related genes in the juvenile prawn, Macrobrachium rosenbergii

In recent years, with the widespread use of TiO2–GO nanocomposite in industry, especially in the remediation of water environments, its toxic effects on aquatic organisms have received increasing attention. As molting is extremely important for crustaceans in their growth, in this study, we cloned the full-length cDNA sequences of two key genes related to molting, nuclear hormone receptor E75 (E75) and nuclear hormone receptor HR3 (HR3), in Macrobrachium rosenbergii, examined the gene expression profile, and investigated their toxicological effects on crustacean molting through nanomaterial exposure. The amino acid sequences for E75 and HR3 were respectively determined to encode 1138 and 363 acid residues. Sequence analysis showed that both E75 and HR3 contain a HOLI domain, with the E75 of M. rosenbergii being more closely related to the E75 of Palaemon carinicauda. These two genes were expressed at the highest levels in muscle, followed by hepatopancreas. The results showed that the expressions of E75 and HR3 in hepatopancreas and muscle tissues were significantly decreased after exposure to 0.1 mg/L of TiO2–GO composite nanoparticles (P < 0.05). This study will serve as a foundation for subsequent research into the evaluation of nanomaterial toxicity on crustacean species.

Effective CO2 Capture and Selective Photocatalytic Conversion into CH3OH by Hierarchical Nanostructured GO-TiO2-Ag2O and GO-TiO2-Ag2O-Arg.

The attenuation of greenhouse gases, especially CO2, as one of the main causes of global warming and their conversion into valuable materials are among the challenges that must be met in the 21st century. For this purpose, hierarchical ternary and quaternary hybrid photocatalysts based on graphene oxide, TiO2, Ag2O, and arginine have been developed for combined CO2 capture and photocatalytic reductive conversion to methanol under visible and UV light irradiation. The material's band gap energy was estimated from the diffuse reflectance spectroscopy (DRS) Tauc analysis algorithm. Structural and morphological properties of the synthesized photocatalysts were studied using various analytical techniques such as Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The calculated band gaps for GO-TiO2-Ag2O and GO-TiO2-Ag2O-Arg were 3.18 and 2.62 eV, respectively. This reduction in the band gap showed that GO-TiO2-Ag2O-Arg has a significant visible light photocatalytic ability. The investigation of CO2 capture for the designed catalyst showed that GO-TiO2-Ag2O-Arg and GO-TiO2-Ag2O have high CO2 absorption capacities (1250 and 1185 mmol g-1, respectively, at 10 bar and 273 K under visible light irradiation). The amounts of methanol produced by GO-TiO2-Ag2O and GO-TiO2-Ag2O-Arg were 8.154 and 5.1 μmol·gcat1·h-1 respectively. The main advantages of this study are the high efficiencies and selectivity of catalysts toward methanol formation. The reaction mechanism to understand the role of hybrid photocatalysts for CO2 conversion is deliberated. In addition, these catalysts remain stable during the photocatalytic process and can be used repeatedly, proving to be enlightening for environmental research.

"IMPROVING THE ELECTROPHYSICAL PROPERTIES OF NANOCOMPOSITE MATERIALS BASED ON GRAPHENE OXIDE AND TIO2"

"This article shows the results related to the study of the effect of graphene oxide on the photoelectric properties of nanostructured titanium dioxide films. A TiO2–GO nanocomposite material with a graphene oxide concentration of 3 wt% was synthesized by hydrothermal method. The Raman and IR spectra of nanocomposite materials have been studied and show the presence of peaks characteristic of graphene oxide and titanium dioxide. In the IR spectra, the so-called Ti-O-C bond is observed, which is responsible for fluctuations between TiO2 and graphene oxide. Studies of absorption spectra show that in a nanocomposite material, the absorption spectrum is shifted to the long-wavelength region of light. Studies of electrophysical properties were carried out using electrochemical impedance spectroscopy. The impedance spectrum of this material shows that there is an improvement when graphene oxide is added to TiO2 films. Photovoltaic parameters also show an increase in the photoinduced current in a nanocomposite material with the addition of graphene oxide by 3 wt%. It is shown that when graphene oxide is added 3 wt% to TiO2, an increase in photocatalytic properties is observed due to an increase in the photoinduced current of the nanocomposite material. "

Perbandingan Karakteristik Sel Superkapasitor Berbahan Komposit GO/TiO2 yang Dibuat Melalui Proses Termal Dengan dan Tanpa Autoclave

The rGO/TiO2 composites were prepared by thermal method using an autoclave and without an autoclave. The rGO/TiO2 composite without an autoclave was prepared from GO dispersion and TiO2 dispersion with a mass ratio of 3:2 through heating at 50 ºC for 5 hours, while the rGO/TiO2 composite with an autoclave was prepared from GO dispersion and TiO2 dispersion with a mass ratio of 3:2 through heating at 120 ºC for 24 hours. As supercapacitor electrodes, the rGO/TiO2 composite layer was deposited on nickel plates (Ni) using the UV Oven spraying technique. The configuration of supercapacitor model was a symmetrical cell that consists of a pair of rGO/TiO2 composite layers on the Ni plate as electrodes and a 1M KOH solution as an electrolyte. The supercapacitor with the electrodes of rGO/TiO2 composite made using autoclaves has higher performance compared to the supercapacitor with the electrodes of rGO/TiO2 composite without autoclave, with the specific capacitance values, specific energy, and specific power of 8.21 F/g, 1.14 Wh/kg, and 164.1 Watt/kg. The performance of the rGO/TiO2 composite supercapacitors are higher than that of supercapacitors using pure GO and TiO2 as electrodes

Synthesis, Characterization and Applications of GO–TiO2 Nanocomposites in Textile Dye Remediation

Synthesis, Characterization and Applications of GO–TiO2 Nanocomposites in Textile Dye Remediation

Tribological properties of Ni–W–TiO2–GO composites produced by ultrasonically–assisted pulse electro co–deposition

The Ni–W–TiO2–Graphene oxide co–deposition with excellent mechanical properties, high wear resistance was produced using ultrasonic–assisted pulse electrodeposition. In the present study, the effects of concentration of graphene oxide and TiO2 particle on the morphology, microstrain, crystallite size, hardness, elastic modulus, and tribological properties of the NiW co–deposition were studied. The morphology, microstructure, and phase analysis of the coatings were investigated using X–ray diffractometer (XRD) and Field Emission Scanning Electron Microscopy (FESEM). X–ray diffraction (XRD) analyses showed that the crystallite size of the Ni(W) matrix decreased with incorporated graphene oxide and TiO2 particles while increased microstrain. Raman analysis is used to confirm the existence of graphene oxide and ceramic particles in the Ni(W) matrix. FESEM results indicated that the Ni–W–TiO2–Graphene oxide co–deposition displayed a compact surface structure, while the crystallite size and microstrain of the composite coating were 7 nm and 3.5 × 10−3, respectively. Nano–mechanical test results showed a maximum of 8.1 GPa and ~209 GPa increases in hardness and elastic modulus with adding graphene oxide and TiO2, respectively. Incorporation of graphene oxide and TiO2 particles into the matrix, the wear rate of the resulting coating can be increased significantly. The tribological behavior of the Ni–W–GO composite coating deposited various graphene oxide concentrations and NiW, Ni–W–TiO2, the Ni–W–TiO2–Graphene oxide coating was compared, and their different wear mechanisms have been discussed. Detailed studies of the worn surface were performed with SEM, EDS, and Raman.

Preparation of Stable Hydrophilic Polyethyleneimine Cross-Linked Graphene Oxide/Titanium Dioxide Membranes for Dye Separation

An excellent novel laminar and hierarchical polyethyleneimine cross-linked graphene oxide/titanium dioxide (GO–TiO2–PEI) membrane was successfully prepared by vacuum filtration technology using polyethyleneimine (PEI) as the cross-linking agent and a GO–TiO2 nanocomposite as the substrate. The resultant membrane (GO–TiO2–PEI) displayed a favorable antifouling performance with bovine serum albumin (BSA) and showed good hydrophilicity and wettability, with a static water contact angle of 13.2∘. The stability of the GO–TiO2–PEI membrane in aqueous solution obviously improved with the cross-linking of PEI compared with that of the GO and GO–TiO2 membranes. The GO–TiO2–PEI membrane also exhibited a satisfactory water flux of 48.6[Formula: see text]L m[Formula: see text] h[Formula: see text] bar[Formula: see text]. The GO–TiO2–PEI membrane exhibited a good performance for effectively separating different dyes including methylene blue (MB), rhodamine B (RB), methyl orange (MO), sunset yellow (SY), new coccine (NC) and amaranth. All the above results suggested that the GO–TiO2–PEI membrane could be used as an excellent stable hydrophilic membrane for efficiently separating dyes from aqueous solution.

A multifunctional sponge incorporated with TiO2and graphene oxide as a reusable absorbent for oil/water separation and dye absorption

Reusable TiO2–GO–SA sponges can be used for the oil/water separation and absorption of oils and dyes.

Remarkable Enhancement of Eu–TiO2–GO Composite for Photodegradation of Indigo Carmine: A Design Method Based on Computational and Experimental Perspectives

Environmental pollution, particularly water contamination, is regarded as one of the most crucial global problems, where a semiconductor photocatalyst towards organic pollutant degradation driven by photocatalysis is a promising technique. Herein, novel Eu–TiO2–GO composites with excellent photocatalytic performance were fabricated via simple and green sol–gel technique. In addition, density functional theory (DFT) method was employed to investigate the electronic structure, stability and charge transfer of the composites. The experimental study revealed that the optimal performance was obtained with the Eu–TiO2–GO (0.6% Eu) composite, of which the apparent rate constant was about 19-folds higher than that of bulk TiO2 because of the combined effects of better visible light absorbance and efficient separation of charge carriers. The efficiency of Eu–TiO2–GO (0.6% Eu) in the degradation of indigo carmine (IC) dye reached 96.78% in 60 min under light irradiation. Based on the DFT method, we observe an efficient electron–hole pair separation, a potential drop and an in-built polarised electric field at the interface of Eu–TiO2–GO composite. Remarkably, Eu–TiO2–GO composite was found to exhibit a stronger interfacial interaction, smaller interlayer distance and a larger redistribution of charge than TiO2–GO composite. The stability and reusability of Eu–TiO2–GO (0.6% Eu) composite as an effective solar photocatalyst was confirmed by five cycling tests of wastewater treatment. From radical quenching experiments, hydroxyl and superoxide radicals were the dominant active species for the photodegradation reaction of IC dye. All these findings may shed light on the intrinsic reasons for the improved degradation of pollutants.

Integral approach of treatment of phenolic wastewater using nano-metal coated graphene oxide in combination with advanced oxidation

Wastewater treatment is one of the highlighted environmental concerns today due to depletion in the underground water table and its serious impact on aquatic life. High organic loading, antibacterial, and phytotoxicity of phenolic compounds in wastewater make them resistant to biological degradation.Therefore, the main aim of the research is to investigate the degradation of phenol by photocatalysis, through a series of Graphene Oxide (GO) coated nanocomposites such as GO-TiO2 (GOT) and Graphene-Iron (GOI). The performance of hybrid composite was investigated in a batch system under different loading conditions such as pH, adsorbent dose, and phenol concentration. Photocatalytic degradation results in complete declination of pollutants into harmless end products. The phenol adsorption by GOT was best and was pH dependant. The optimum condition for 97.78% removal by GOT was achieved at an adsorbent dose of (0.210 g /L), pH (5.5), phenol concentration (10 mg/L), and contact time 2 h. But the major drawback of GOT is recovery and separation, to overcome this GOI was synthesized. GOI represents lesser adsorption capability of (53.89%) because of the loading of iron on GO sheet. Langmuir and Freundlich both isotherm models represented well fit for the phenol adsorption batch data. However, the Langmuir isotherm (R2=0.999) shows a better fit over the Freundlich model (R2=0.964). Further in the study, the photocatalytic degradation by GOT were optimized using response surface methodology (RSM) and Artificial Neural Network (ANN) analysis.

Sonochemical synthesis of nanospherical TiO2 within graphene oxide nanosheets and its application as a photocatalyst and a Schottky diode

The hybrid of graphene oxide (GO) nanosheets with well embedded nanospherical TiO2 was prepared through mechanical mixing using ultrasound. This modified TiO2-GO (TGO) composite exhibits reduced recombination of charge carriers. Benefiting from unique morphology and surface area (92 m2g−1), the TGO composite showed remarkable catalytic activity for the photodegradation of congo red (CR) and methyl orange (MO). The rate constant values were 0.0652 min−1 (pseudo first order) for CR (5 ppm) and 0.0631 min−1 for MO (5 ppm). The stability and aggregation behavior of TGO was examined using the dynamic light scattering (DLS) technique. The key parameter affecting photocatalytic performance is electron-hole separation. To illustrate this issue, a Schottky diode has been fabricated with TGO composite, in contact with aluminium. Important diode parameters i.e. ideality factor, series resistance, barrier height have been estimated from forward current-voltage (I-V) characteristics. Space charge limited current (SCLC) theory was employed to provide insight into the carrier transport properties of TGO and enhanced carrier mobility (2.11.10−6 m2V−1s−1) and low transit time (0.237.10−6 s) under illumination was obtained. The composite appears suitable for energy and photocatalytic applications.

Using 3-Isocyanatopropyltrimethoxysilane to Decorate Graphene Oxide with Nano-Titanium Dioxide for Enhancing the Anti-Corrosion Properties of Epoxy Coating.

In this paper, the graphene oxide loaded with nano titanium dioxide (TiO2–GO) was synthesized through 3-isocyanatopropyltrimethoxysilane (IPTMS) and characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and dispersion test. The results illustrated our modification was successful and TiO2–GO was transferred from hydrophilic to hydrophobic. That greatly enhanced the dispersity of TiO2–GO in epoxy through the observation of the coating morphology test. Moreover, the impact of TiO2–GO on anti-corrosion property in epoxy was investigated by Electrochemical Impedance Spectroscopy (EIS). Comparing to pristine particles including GO and TiO2, TiO2–GO could more significantly improve the resistance of corrosion with the help of IPTMS. Furthermore, the anti-corrosion mechanism of TiO2–GO in epoxy was tentatively proposed and discussed.

Pulsed Laser Ablation in Water Synthesis of Black TiO2-Graphene Oxide Nanocomposites and the Enhanced Photocatalytic Performance

Black TiO₂-graphene oxide (GO) nanocomposites are synthesized via the pulsed laser ablating TiO₂ powders and GO in deionized water. The simple process enables the preparation of black TiO₂ nanoparticles and anchors them onto the GO sheet in one step. The TiO₂-GO nanocomposites exhibit greatly enhancement for photocatalytic degradation of Rhodamine B (RB) dye in comparison with the pristine and the ablated black TiO₂. The heterojunction structure plays an important role in efficient charge separation, which reduces the recombination of photogenerated electrons and holes. The unique two-dimensional structure of GO enables the composite to have a large specific surface area, and prevents the agglomeration of TiO₂ nanoparticles, which are beneficial to the photocatalytic performance of the composite.

Synergistic RGO/Black TiO2/2D‐ZIF‐8 Ternary Heterogeneous Composite with Highly Efficient Photocatalytic Activity

AbstractA ternary heterogeneous composite combining reduced graphene oxide (RGO), black titanium dioxide (B−TiO2) nanosheets and two dimensional ZIF‐8 sheets (2D‐ZIF‐8) was prepared. Under hydrothermal condition, B−TiO2 nanosheets and GO were tightly bound together, and meanwhile GO was reduced to RGO. Upon mixing with poly (vinyl pyrrolidone) (PVP)‐modified 2D‐ZIF‐8, the RGO/B−TiO2/2D‐ZIF‐8 ternary composite was obtained by PVP binding between B−TiO2 and 2D‐ZIF‐8. The introduction of 2D‐ZIF‐8 endowed the ternary composite a good adsorption capability of contaminant and followed degradation in situ at the site of adsorption. Owing to synergistic catalysis of oxygen vacancy and the formation of double heterogeneous interfaces, the prepared ternary composite had good visible light adsorption and rapid charge separation rate, which improved the photocatalytic performance. The rate constant of photocatalytic degradation of doxycycline hydrochloride and methylene blue by RGO/B−TiO2/2D‐ZIF‐8 was determined to be 0.0118 and 0.0232 min−1, respectively, which are 2.68 and 3.3 times that of B−TiO2. This study could provide deep insight for the design of high and bi‐functional activity catalysts based on the assembly of two‐dimensional sheet.

Effect of TiO2 content on the properties of polysulfone nanofiltration membranes modified with a layer of TiO2–graphene oxide

Graphene oxide (GO)-based membranes have been widely used for molecular separation due to their size exclusion effect. However, it remains a challenge to prepare a structurally stable, freestanding GO-based membrane that exhibits efficient separation. Herein, GO nanofiltration (NF) membranes with different loadings of TiO2 (TiO2@GO) were successfully prepared on top of a polysulfone (PSF) support layer and showed high efficiency in dye separation/desalination, along with antifouling and antibacterial activity. The resulting TiO2@GO NF membranes also showed excellent structural stability. The membrane prepared with the same contents of GO and TiO2 (NFG-2) exhibited high dye rejection (>98%) and low Na2SO4 rejection (<6%) and thus could be applied in the treatment of dye wastewater. Moreover, its permeation flux (3.6 L·m−2·h−1·bar−1) and dye rejection (98.0%) remained constant at high levels after 9 h of operation. Antifouling and antibacterial properties were also observed. This new kind of NF membrane may be a promising candidate for use in dye separation and desalination applications.

Fabrication of TiO2 Reduced Graphene Oxide Based Nanocomposites for Effective of Photocatalytic Decolorization of Dye Effluent

Reduced graphene oxide (RGO) were successfully prepared through chemical reduction of GO that was prepared by modified Hummer’s method. Characterization of GO and RGO was performed using different techniques and they were trapped in acrylic acid (PAAc) and polyvinyl alcohol (PVA) to form (PVA/PAAc)–GO and (PVA/PAAc)–RGO nanocomposites using gamma irradiation technique. Characterization the prepared nanocomposite was investigated using X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and transmission electron microscopy (TEM). TiO2 was also trapped in the nanocomposite matrix to perform (PVA/PAAc)–GO–TiO2 and (PVA/PAAc)–RGO–TiO2 nanocomposite hydrogels. It was found that the crystallite size of (PVA/PAAc)–TiO2, (PVA/PAAc)–GO–TiO2 and (PVA/PAAc)–RGO–TiO2 nanocomposite calculated using Debye–Scherrer’s equation are 52.8, 26.02, and 23 nm, respectively. The surface morphology explained a good dispersion of GO within (PVA/PAAc)–GO–TiO2 and (PVA/PAAc)–RGO–TiO2 appears as a porous structure. The photocatalytic activity of the obtained nanocomposites was tested for the photodecolorization of direct blue 71 dye (DB71) in the aqueous medium under UV light. A complete decolorization of DB71 was achieved after 40 min at pH 6 in the presence of 2 mL/L hydrogen peroxide. The rate of photodecolorization follows Langmuir Hinshelwood pseudo-first-order kinetics. It was also obtained that (PVA/PAAc)–RGO–TiO2 nanocomposites can be reused for ten times with full activity.

Photocatalytic degradation of organophosphorus pesticide using semiconductor-sensitized composite in natural water: effect of oxidants

In this work, dichlorvos was degraded with photocatalytically active n-type semiconductors and p–n junction-type semiconductors. The p–n junction-type semiconductors such as GO–TiO2 (GO = graphene oxide) and GO–WO3 were synthesized by photodeposition method using commercial TiO2 and WO3. GO-doped nano-TiO2 was synthesized through sol–gel technique from titanium(IV) isopropoxide by hydrothermal treatment. The synthesized materials were characterized by different techniques such as XRD, UV, FTIR, SEM and TEM. In order to find out the photocatalytic ability towards degradation of dichlorvos, the experiment was carried out in an aqueous suspension under UV light in the presence of oxygen and oxidants such as H2O2 and K2S2O8. From the evaluation, GO–nano-TiO2 with H2O2 was found to be highly active that showed complete degradation of dichlorvos within 15 min under UV light.

On the role of a graphene oxide/titania catalyst, visible LED and ozone in removing mixtures of pharmaceutical contaminants from water and wastewater

Pharmaceuticals removal by photocatalytic ozonation: evaluation of radiation fluence, GO content and GO–TiO2 dosage synergies in ultrapure water photocatalytic ozonation. Two reaction kinetic periods proposed for wastewater photocatalytic ozonation.