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Creating innovative catalysts utilizing nonprecious metals for the electrocatalytic hydrogen evolution reaction (HER) poses a significant difficulty. We present a cobaloxime (Cox) complex having pyridine (2-Cox) and tetrafluorophenyl-thio-pyridine (4-Cox) functional groups, which contains a 4,4-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) moiety. This combination serves as a catalyst for proton reduction and is immobilized onto reduced graphene oxide (rGO) by π–π stacking between the cobaloxime complex and rGO. Moreover, the unique complex's structures were determined through the application of ultraviolet–visible spectroscopy (UV–Vis), Fourier Transform Infrared spectroscopy (FT-IR), X-ray diffraction spectroscopy (XRD), and scanning electron microscopy (SEM). The electrocatalytic activity of the two rGO/2-Cox and rGO/4-Cox electrodes towards hydrogen (H 2) were examined under both alkaline and acidic conditions. The cobaloxime-modified rGO electrodes demonstrate superior electrocatalytic performance for the HER under acidic conditions compared to alkaline conditions. The overpotential at a current density of 10 mA cm−2 for rGO/2-Cox in 0.5 M H 2 SO 4 is −0.342 V, which is notably lower than the overpotential of rGO/4-Cox (−0.496 V). The Tafel slope for the rGO/2-Cox electrode in a 0.5 M H 2 SO 4 solution is 111 mV.dec−1, but for the rGO/4-Cox electrode it is 156 mVdec−1. This discrepancy suggests that the rGO/2-Cox electrode demonstrates better performance in the HER compared to the rGO/4-Cox electrode. • Two different BODIPY-cobaloxime complexes were synthesized. • These combinations are immobilized on reduced graphene oxide by π-π stacking. • The electrocatalytic activity of these structures towards hydrogen was studied. • 2-Cox structure exhibited superior electrocatalytic performance for HER. • These catalysts have the potential to be used in various energy applications. [ABSTRACT FROM AUTHOR]

AbstractThe current study aimed to the preparation of graphene oxide impregnated chitosan– polyvinyl alcohol hybrid beads (GO/CS-PVA) for the removal of Reactive Black 5 (RB5) dye from wastewater solutions, presenting them as a cost-effective alternative for wastewater treatment. These hybrid beads were fabricated using a dripping technique in an aqueous solution. The surface and structure of the material before and after adsorption process were studied by analyzing FTIR spectroscopy and Scanning electron microscope (SEM) as well as adsorption capacity was also evaluated. The results proved the successful synthesis of GO/CS-PVA beads and elucidated the physical adsorption mechanism of RB5. SEM images revealed uniform spherical beads with a rough surface, approximately 752 μm in diameter. Additionally, the evaluation of adsorption capacity showed that the optimum condition for RB5 adsorption is at pH = 3 while the kinetic investigations revealed that the adsorption process adhered to the pseudo-second-order model, indicating a chemisorption reaction. Furthermore, an increase in temperature from 25 to 65 °C enhanced the maximum adsorption capacity of GO/CS-PVA beads by 34%. The cytotoxic effect of the hybrid as measured on adipose derived stem cells via the MTT assay was negligible. In conclusion, it was proved that the eco-friendly GO/CS-PVA beads adsorbents can efficiently remove RB5 from wastewater in practical applications. [ABSTRACT FROM AUTHOR]

Background: The world society is still suffering greatly from waterborne infections, with developing countries bearing most of the morbidity and death burden, especially concerning young children. Moreover, microbial resistance is one of the most prevalent global problems that extends the need for self-medication and the healing period, or it may be linked to treatment failure that results in further hospitalization, higher healthcare expenses, and higher mortality rates. Thus, innovative synthesis of new antimicrobial materials is required to preserve the environment and enhance human health. Results: The present study highlighted a simple and cost-effective approach to biosynthesize a chitosan/graphene oxide/zinc oxide nanocomposite (CS/GO/ZnO) alone and immobilized in a macroporous cryogel as a new antimicrobial agent. Bacillus subtilis ATCC 6633 was used as a safe and efficient bio-nano-factory during biosynthesis. The formation of CS/GO/ZnO was confirmed and characterized using different analyses including ultraviolet-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), selective area diffraction pattern (SADP), Zeta analyses, scanning electron microscope (SEM) and transmission electron microscopy (TEM). GO combined with ZnO NPs successfully and displayed an adsorption peak at 358 nm. The XRD results showed the crystalline composition of the loaded ZnO NPs on GO sheets. FTIR spectrum confirmed the presence of proteins during the synthesis which act as stabilizing and capping agents. The nanocomposite has a high negative surface charge (-32.8 ± 5.7 mV) which increases its stability. SEM and TEM showing the size of biosynthesized ZnO-NPs was in the range of 40–50 nm. The CS/GO/ZnO alone or immobilized in cryogel revealed good antimicrobial activities against B. cereus ATCC 14,579, Escherichia coli ATCC 25,922, and Candida albicans ATCC 10,231 in a dose-dependent manner. The CS/GO/ZnO cryogel revealed higher antimicrobial activity than GO/ZnO nanocomposite and standard antibiotics (amoxicillin and miconazole) with inhibition zones averages of 24.33 ± 0.12, 15.67 ± 0.03, and 17.5 ± 0.49 mm, respectively. The MIC values of the prepared nanocomposite against B. cereus, E. coli, and C. albicans were 80, 80, and 90 µg/ml compared to standard drugs (90, 120 and 150 µg/ml, respectively). According to the TEM ultrastructure studies of nanocomposite-treated microbes, treated cells had severe deformities and morphological alterations compared to the untreated cells including cell wall distortion, the separation between the cell wall and plasma membrane, vacuoles formation moreover complete cell lyses were also noted. In the cytotoxicity test of CS/GO/ZnO alone and its cryogel, there was a significant reduction (p˂0.05) in cell viability of WI-38 normal lung cell line after the concentration of 209 and 164 µg/ml, respectively. It showed the low toxic effect of the nanocomposite and its cryogel on the WI-38 line which implies its safety. In addition, water treatment with the CS/GO/ZnO cryogel decreased turbidity (0.58 NTU), total coliform (2 CFU/100 ml), fecal coliform (1 CFU/100 ml), fecal Streptococcus (2 CFU/100 ml), and heterotrophic plate counts (53 CFU/1 ml) not only in comparison with the chlorine-treated samples (1.69 NTU, 4 CFU/100 ml, 6 CFU/100 ml, 57 CFU/100 ml, and 140 CFU/1 ml, respectively) but also with the raw water samples (6.9 NTU, 10800 CFU/100 ml, 660 CFU/100 ml, 800 CFU/100 ml, and 4400 CFU/1 ml, respectively). Moreover, cryogel significantly decreased the concentration of different heavy metals, especially cobalt compared to chlorine (0.004 ppm, 0.002 ppm, and 0.001 ppm for raw water, chlorine-treated, and cryogel-treated groups, respectively) which helped in the reduction of their toxic effects. Conclusion: This study provides an effective, promising, safe, and alternative nanocomposite to treat different human and animal pathogenic microbes that might be used in different environmental, industrial, and medical applications. [ABSTRACT FROM AUTHOR]

This study explores fabrication and characterization of mixed matrix membranes (MMMs) for gas separation, employing a cost‐effective solution casting method. Polycarbonate (PC) and polystyrene (PS) blends are combined with graphene oxide (GO) and zirconium dioxide (ZrO2) nanofillers, with and without a deep eutectic solvent (DES) obtained through hydrogen bond exchange. Various MMMs compositions (2–20 wt%) are systematically examined using diverse characterization techniques, including differential scanning calorimetry, thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, porosity determination, and water contact angle analysis. The MMMs exhibit enhanced gas permeability and selectivity, surpassing conventional membrane materials. Notably, H2 gas permeability reaches outstanding levels, with the composition PC/PS‐DES‐GO/ZrO2 at 20 wt% (PBC20‐IV) demonstrating the highest value of 86.32 Barrer. This superior performance is attributed to the unique properties of ZrO2, increased sorption capacity of GO, and enhanced thermal stability due to DES. Permeability data for CO2, N2, O2, and CH4 also show significant values, aligning with the observed trends in H2 permeability. Robeson's plot for the H2/CO2 gas pair surpasses the 2008 upper bound, placing the MMMs in a novel category for gas separation membranes. The incorporation of DES‐modified nanofiller blend composites presents a promising strategy for the potential production of pure hydrogen. [ABSTRACT FROM AUTHOR]

In the current work, a novel and simple electrochemical sensing platform was built utilizing a graphene oxide (GO)/metal–organic framework-235 (MOF-235) nanocomposite, which was successfully synthesized and used as an excellent modifier to determine the simultaneous presence of two key anticancer medications, daunorubicin (DNR), and dacarbazine (DTIC). Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, field-emission scanning electron microscopy, and scanning electron microscopy (SEM) are used to characterize the GO/MOF-235 nanocomposite. The electrocatalytic properties of the modified sensor based on MOF and GO in phosphate buffer solution (PBS) (0.1 M—pH 7.0) toward DNR redox reaction were thoroughly investigated using electrochemical methodologies including cyclic voltammetry, differential pulse voltammetry, and chronoamperometry. This GO/MOF-235-modified CPE demonstrated a wide linear response of 0.005–400.0 μM under optimized conditions. It was determined that 0.002 μM was the detection limit. This sensor displayed two distinct oxidation peaks at 390 mV for DNR and at 750 mV for dacarbazine (DTIC) (peak potential separation = 360 mV), allowing for the simultaneous detection of the two anticancer medications. Determination of these anticancer medicines in samples (DNR injection and DTIC injection) was effectively accomplished in the final step using the GO/MOF-235/CPE sensor. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide (rGO) and lanthanum strontium manganite (LaSrMnO3) have been widely studied for various applications due to their amazing physicochemical properties. This work explains the influence of reduced graphene oxide in LaSrMnO3 perovskite, i.e., rGO@LaSrMnO3 nanocomposite for supercapacitor application. A facile combustion route was employed to synthesize rGO@LaSrMnO3 nanocomposites as promising electrode materials for supercapacitors. XRD analysis confirmed the perovskite structure of LaSrMnO3, while FESEM and EDAX revealed intimate interfacial contact between rGO nanosheets and LaSrMnO3 nanoparticles. BET measurements demonstrated a significant increase in surface area due to rGO incorporation, while FTIR spectroscopy confirmed the presence of oxygen vacancies. XPS analysis further corroborated the composite's reduced graphene oxide state and Mn3⁺ oxidation states. Consequently, the rGO@LaSrMnO3 (15R) electrode exhibited a remarkable specific capacitance of 1417.1 F/g at 1 A/g. This enhanced performance is attributed to the synergistic effect high electrical conductivity of rGO and the pseudocapacitive behavior of LaSrMnO3. This work presents a rapid and scalable approach for fabricating high-performance supercapacitor electrodes with improved capacitance and cyclability. [ABSTRACT FROM AUTHOR]

Supercapacitors have drawn a lot of interest as energy storage devices because of their high-power density, quick charge/discharge rates, and long cycle life. However, the creation of cutting-edge electrode materials is essential in order to further improve their performance. Nanostructures made of graphene-based conducting polymers have shown promise because they combine the special qualities of both graphene and conducting polymers. In the present research, we synthesized the composites of reduced graphene oxide and polypyrrole conducting polymer by in situ chemical polymerization by varying their mass ratio. The fabricated samples were characterized by FTIR spectroscopy, Raman spectroscopy, TEM, XPS, XRD, and cyclic voltammetry for further analyses for these nanostructures' potential application in energy storage devices. Composite fabrication was verified through FTIR and Raman spectroscopy by confirming distinct peaks. TEM studies confirmed the presence of thin and randomly aggregated graphene oxide nanoparticles. XPS survey spectra identified carbon, nitrogen, and oxygen, with major peaks at 284 eV, 399 eV, and 531 eV, reflecting variations in C, N, and O. Cyclic voltammetry determined specific capacitance values of 4.66 F/g and 6.11 F/g for different mass ratios of polypyrrole and reduced graphene oxide. [ABSTRACT FROM AUTHOR]

Nano-ZnO/graphene composites were directly synthesized at 195 °C via the thermal reduction of graphene oxide (GO) through low-temperature heat treatment at low pressure by using ZnO nanoparticles and GO powders as raw materials. The prepared composites were characterized through X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, photoluminescence spectroscopy, and UV–vis diffuse reflectance spectroscopy. The samples' ability to degrade methylene blue (MB) was tested under simulated sunlight. Results indicated that after the introduction of GO, ZnO underwent lattice distortion. Nano-ZnO grains were loaded onto graphene, and the interface between ZnO and graphene was well bonded. The addition of GO enhanced the absorbance of the samples. The addition of an appropriate amount of GO reduced the fluorescence intensity of the samples. The synthesized ZnO/graphene composites had good photocatalytic properties. When the GO content of the raw material was 20 mol%, the samples exhibited excellent photocatalytic activity and degraded MB within 30 min. [ABSTRACT FROM AUTHOR]

In this study, titanium dioxide (TiO2) nanoparticles were obtained via a hydrothermal method, while graphene oxide (GO) nanoparticles were produced via Hummers' method. Reduced graphene oxide/titanium dioxide (RGO@TiO2) nanocomposites were synthesized via a hydrothermal technique. The structural, morphological, and optical properties of TiO2, RGO@TiO2, and perovskite nanoparticles were characterized via powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible spectrophotometry. Fourier transform infrared spectroscopy (FTIR) was used to study the functional groups in the samples. Additionally, thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were also used to investigate how samples undergo structural and phase changes throughout a thermal process. This study investigated the enhancement of cell efficiency with lightening. In this work, FTO/Ag/TiO2/perovskite/spiro-OMeTAD/Ag, FTO/Ag/RGO@TiO2/perovskite/spiro-OMeTAD/Ag, and FTO/Ag/perovskite/spiro-OMeTAD/Ag structured solar cell devices were fabricated and subjected to two different light treatments, ultraviolet (UV) and LED lamps, to determine how cell efficiency is affected by light. After lighting with a 7-W LED lamp, the perovskite solar cells (PSCs) with the structure of FTO/Ag/RGO@TiO2/perovskite/spiro-OMeTAD/Ag showed a higher efficiency of 17.01% compared with that of the other materials, FTO/Ag/perovskite/spiro-OMeTAD/Ag 8.61%, and FTO/Ag/TiO2/perovskite/spiro-OMeTAD/Ag 15.62%. It can be concluded that using the RGO@TiO2 nanocomposite material in the fabrication of PSCs enhanced the cell efficiency. [ABSTRACT FROM AUTHOR]

Drug-eluting stents are commonly utilized for the treatment of coronary artery disease, where they maintain vessel patency and prevent restenosis. However, problems with prolonged vascular healing, late thrombosis, and neoatherosclerosis persist; these could potentially be addressed via the local generation of nitric oxide (NO) from endogenous substrates. Herein, we develop amine-functionalized graphene as a NO-generating coating on polylactic acid (PLA)-based bioresorbable stent materials. A novel catalyst was synthesized consisting of polyethyleneimine and polyethylene glycol bonded to graphene oxide (PEI-PEG@GO), with physicochemical characterization using x-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. In the presence of 10 μM S-nitrosoglutathione (GSNO) or S-nitroso-N-acetylpenicillamine (SNAP), PEI-PEG@GO catalyzed the generation of 62% and 91% of the available NO, respectively. Furthermore, PEI-PEG@GO enhanced and prolonged real-time NO generation from GSNO and SNAP under physiological conditions. The uniform coating of PEI-PEG@GO onto stent material is demonstrated via an optimized simple dip-coating method. The coated PLA maintains good biodegradability under accelerated degradation testing, while the PEI-PEG@GO coating remains largely intact. Finally, the stability of the coating was demonstrated at room temperature over 60 days. In conclusion, the innovative conjugation of polymeric amines with graphene can catalyze the generation of NO from S-nitrosothiols at physiologically relevant concentrations. This approach paves the way for the development of controlled NO-generating coatings on bioresorbable stents in order to improve outcomes in coronary artery disease. [ABSTRACT FROM AUTHOR]

Hazardous microorganisms and poisonous pigments found in industrial effluent can have detrimental effects on the environment and human health. This study investigates the synthesis and characterization of graphene oxide (GO), silver oxide (Ag2O) nanoparticles (NPs), and graphene oxide-based silver oxide (GO/Ag2O) nanocomposite, highlighting their enhanced antibacterial and visible light-driven photocatalytic activities. Modified Hummers' method, sol-gel auto-combustion method, and low-cost sonication method were used to prepare GO, Ag2O NPs, and GO/Ag2O nanocomposite with different wt% (1, 5, 10, and 15) of GO, respectively. These synthesized materials were characterized using various characterization techniques such as, UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscope (SEM), and Transmission electron microscope (TEM). Particle size was calculated using Gaussian fitting of XRD, which was found to increase from 20 to 25 nanometres (nm). The optical energy band gap was calculated using a Tauc plot, which decreased from 1.77 to 1.14 electron Volts (eV), respectively. The valence state of Ag (Ag+) for Ag2O, GO-1/Ag2O, and GO-15/Ag2O are confirmed by X-ray photoelectron spectroscopy (XPS). The degradation of methylene blue (MB) dye was done in exposure to sunlight at various time periods using these synthesized materials as photocatalysts to evaluate their photocatalytic activity. GO (15 wt%)/Ag2O nanocomposite showed the best photocatalytic activity among all synthesized materials by the degradation of MB dye to 90% in 120 min under the sun. In addition to excellent photocatalytic activity, GO (15 wt%)/Ag2O nanoparticles exhibited excellent antimicrobial activity. It showed the highest inhibitory range and lowest inhibitory concentration against Staphylococcus aureus and Escherichia coli among all synthetic materials. This demonstrates its potential as a versatile material with excellent photocatalytic and antimicrobial properties, making it promising for many applications in environmental and medical care. [ABSTRACT FROM AUTHOR]

It is imperative to improve the physical, morphological, and mechanical properties of biodegradable polymers like polylactic acid (PLA), poly (butylene adipate‐co‐terephthalate) (PBAT), and polycaprolactone (PCL) in order to employ them on a larger scale. The development of hybrid nanocomposite materials using nano inclusions can improve desired qualities. Here we introduced an interactive nano reinforcement approach to improve the properties by combining graphene oxide (GO) and carboxyl functionalized MWCNT (f‐MWCNT), to provide for their chemical bonding for synergic reinforcement. A constant filler 2 wt.% was added to the biopolyesters by melt blending process and examined the different physical properties like water absorption, intrinsic viscosity, and hardness. To completely evaluate the functionalization of the nanofillers, wide‐angle X‐ray diffraction (WAXD), Raman spectroscopy and Fourier transform infrared radiation (FTIR) analyses were used. The paired nanoparticles and polymer matrix appear to mix well together, as shown by electron microscopy, which also reveals good dispersion and the creation of a reinforcing network microstructure across the matrix layer. A thorough analysis of the results showed that effective stress transmission, delaying the start of faults and generating microcracks, and dissipating additional mechanical energy all contributed to efficient hybrid network formation, which improved the mechanical properties of hybrid filler nanocomposites except some nanocomposites. These findings offer a viable technique for chemically altering biodegradable polymers, like PLA, PBAT, and PCL for use in biomedical, wastewater management, and agricultural applications. [ABSTRACT FROM AUTHOR]

In the present study, a quaternary composite consisting of α-ketoglutaric acid, chitosan, polyaniline, and graphene oxide (α-CTS-PANI-GO) was synthesized and characterized by Scanning Electron Microscope, Fourier Transform Infrared Spectroscopy, and Raman spectroscopy. The adsorption of dye on the film was proved by the X-ray diffraction analysis method. According to the increase in the intensity of the peak before and after adsorption, it showed the presence of Methylene Blue (MB) and Acid Orange 7 (AO7). Also, the appearance of peaks related to sulfur in Energy dispersive X-ray (EDX) and EDX elemental mapping, and X-ray photoelectron spectroscopy data after the adsorption process proved the presence of dyes compounds and their adsorption by the synthetic film. The simultaneous removal properties of α-CTS-PANI-GO were evaluated in the removal of cationic and anionic dyes, MB and AO7. Using the Central Composite Decomposition, the effect of different variables such as pH, temperature, adsorbent dose, and time on AO7 and MB removal was studied. The regeneration of α-CTS-PANI-GO film was studied and the zero point charge of the synthesized film was also determined. Various isotherm models, such as Langmuir and Freundlich, were investigated, and the processing of experimental equilibrium data confirmed the suitability and application of the Langmuir model. Analysis of experimental adsorption data using various kinetic models, such as pseudo-first and second-order models, shows the applicability of the first-order equation. The results showed that in the optimal conditions, the removal percentage was about 95% for AO7 and 80% for MB, which indicates the successful performance of the synthetic film compared to the method. [ABSTRACT FROM AUTHOR]

This study describes an easy and cheap inkjet printing method for producing a paper-based gas sensor consisting of a composite film made of graphene oxide and poly(3,4-ethylenedioxythiophene) and poly(styrenesulfonate) (PEDOT:PSS). A glossy paper substrate is an inkjet printed with ink made by dispersing graphene oxide in a PEDOT:PSS conducting polymer solution to test its ability to detect ammonia ( NH 3) at ambient temperature. The presence of few-layer graphene oxide in the PEDOT:PSS copolymer and the existence of π – π interactions between graphene oxide and PEDOT:PSS are confirmed by Fourier transform infrared spectroscopy, UV–Visible spectrophotometer, and X-ray diffraction. In a small concentration range of 1–100 ppm at ambient temperature, the ink-jet printed graphene oxide-PEDOT:PSS gas sensor displays strong responsiveness and good selectivity to NH3. The study found that NH 4 is a strong donor in the ammonia gas produced by a bubble system of ammonia water, with NH 4 molecules being ideal candidates for molecular doping of graphene. The H 2 O molecule can facilitate quick desorption by converting NH 3 to NH 4 . The interaction between graphene oxide and NH 3 molecules is weak. The attained gas-sensing performance may be attributed to the increased specific surface area of graphene oxide and enhanced interactions between the sensing film and NH 3 molecules via π and lone pair electron network. The NH 3 -sensing mechanisms of the flexible printed gas sensor are based on the competitive interaction of ammonia on the sensor, adsorption and dissociate ionization on the sensor surface. [ABSTRACT FROM AUTHOR]

In recent years, antibiotics in aqueous solutions have drawn extensive attention due to their harmful effect on human health and the environment. In this study, efficient and rapid adsorption of two antibiotics, including tetracycline (TC) and cefazolin (CFZ) on synthesised montmorillonite (Mt)/nano zero-valent iron (nZVI)/graphene oxide (GO) from aqueous solutions was studied. The prepared adsorbent was characterised by scanning electron microscope (SEM), energy dispersive X-Ray (EDX), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), and vibrating sample magnetometer (VSM). One-factor-at-a-time (OFAT) method was used to optimise the experimental factors. The maximum removal percentage was achieved at pH of 7, an adsorbent dosage of 0.4 g, contact time of 7 min = TC and 10 min = CFZ, initial concentration of 5 mg L−1, and a temperature of 298 K. The evaluation of isotherm models indicated that the Langmuir isotherm with a coefficient of determination (R2) value of 0.9992 for both antibiotics was selected as the best fitting model to describe the adsorption process. The maximum adsorption capacities (qmax) of Mt-nZVI-GO were obtained at 43.24 mg g−1 for TC and 20.36 mg g−1 for CFZ. Furthermore, the pseudo-second-order (PSO) kinetic model fitted well for TC (R2 = 0.9937) and CFZ (R2 = 0.9997). Thermodynamic parameters, i.e. adsorption Gibbs free energy (ΔG0), standard enthalpy (ΔH0), and standard entropy (ΔS0) were estimated. It was found that the adsorption had spontaneous and exothermic in nature. The results revealed that Mt-nZVI-GO could be used as a simple, efficient, and eco-friendly adsorbent for the simultaneous removal of contaminants in aqueous media. [ABSTRACT FROM AUTHOR]

Adding graphene microflakes with excellent mechanical properties to asphalt materials can promote the development of sustainable transportation infrastructure. Recently, graphene oxide–modified asphalt has gained popularity due to its enhanced storage stability, ease of construction, and high-temperature stability. However, the modification mechanism of graphene oxide and polymer modifiers within asphalt remains unclear. This study aims to investigate the mechanism of action of aminated graphene oxide and styrene-butadiene-styrene (SBS) within asphalt and elucidate their influence on the properties of composite-modified asphalt. This research utilized X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), dynamic shear rheometer (DSR), multiple stress creep recovery (MSCR), bending beam rheometer (BBR), and thermogravimetry analysis (TGA) to explore the performance of composite-modified asphalt and the modification mechanism of modifiers. X-ray diffraction and Fourier transform infrared spectroscopy showed that the modification effect was better, the surface wrinkles of modified graphene oxide increased, and the interlayer spacing expanded, which was favorable to its compatibility with asphalt. Conventional test and Brookfield viscosity revealed that composite-modified asphalt possessed favorable high-temperature resistance and plasticity compared to the original asphalt. Additionally, dynamic shear rheological and storage stability tests indicated that the addition of aminated graphene oxide not only improved the viscoelastic properties of asphalt but also enhanced the compatibility between various substances. Multiple stress creep recovery and bending beam rheometer tests measurements confirm that the composite-modified asphalt exhibits superior high-temperature rutting resistance and low-temperature crack resistance. Fluorescence microscopy analysis demonstrated the uniform distribution of the modifier and SBS within the asphalt, while thermogravimetry analysis revealed that composite-modified asphalt exhibited higher thermal stability compared to SBS-modified asphalt. This study holds significant importance in advancing the development and practical application of road modification materials. [ABSTRACT FROM AUTHOR]

In this study, we provide electrochemical techniques for synthesizing thermally reduced graphene nanomaterial that have high potential, low defects, cost-effectiveness, and ecological sustainability. The electrochemical exfoliation is carried out by employing a 195 W DC (voltage = 60 V and current = 3.25 A) power source at a maximum electrolyte temperature of about 92.5∘C within the aqueous suspension of 2 M of sulfuric acid (H2 SO 4). Thereafter, the synthesized nanomaterial was treated in the weak piranha [combination of sulfuric acid and hydrogen peroxide (H2 O 2) ] solution using an electrochemical technique inside the water bath sonicator at 80∘C. X-ray diffraction (XRD) analysis shows the peak of diffraction to the (002) plane of the reduced graphene oxide (RGO) samples emerges at around 2 θ = 2 6. 4 0 ∘ and 26.56∘ with an interplanar distance of 3.40 Å and 3.54 Å. According to the XRD data, after the high-temperature thermal reduction phase, the structure of the crystals and interplanar separation were recovered. The size of the crystallite of RGO produced under H2SO4 conditions was discovered to be greater than the crystallite size of graphene oxide produced under piranha solution conditions. The Raman analysis results show that the degree of disorder of the graphene synthesized within the H2O2 was higher than in comparison to the graphene synthesized in H2SO4. Field emission scanning electron microscopy (FE-SEM) results show that graphene synthesized in the presence of H2O2 has a thin and porous microstructure in comparison to H2SO4 with no significant effect on the presence of the availability of the C/O ratio. The atomic force microscopy (AFM) analysis indicates that the surface roughness of the graphene synthesized in the H2O2 was higher than that of the H2SO4. The Fourier transform infrared spectroscopy (FT-IR spectroscopy) analytical results show that the majority of the functional groups have been eliminated within the samples. [ABSTRACT FROM AUTHOR]

AbstractGraphene oxide (GO) is widely used in bone tissue engineering due to its good biocompatibility and proliferation, and is often used in combination with other hydrogels, which not only reduces the cytotoxicity of GO but also improves the mechanical properties of the hydrogels. We developed injectable carboxymethyl chitosan (CMC)/hydroxyethyl cellulose (HEC)/β-tricalcium phosphate (β-TCP)/GO hydrogel via hydrogen bonding cross-linked between (CMC) and (HEC), also, calcium cross-linked by β-TCP was also involved to further improvement of mechanical properties of the hydrogel, and incorporate different concentration of GO in these hydrogel systems. The characterization of the novel hydrogel was tested by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The swelling ratio and mechanical properties were investigated, the results showed that the addition of GO was able to reduce the swelling rate of hydrogels and improve their mechanical properties, with the best effect in the case of 1 mg/mL content. In vivo experimental studies showed that the hydrogel significantly promoted the osteogenic differentiation of rat bone marrow mesenchymal stem cells (rBMSCs), with the best effect at a concentration of 2 mg/mL. The results of the cellular experiments were similar. Therefore, the novel environment-friendly and non-toxic injectable CMC/HEC/β-TCP/GO hydrogel system may have potential applications in bone tissue engineering. [ABSTRACT FROM AUTHOR]

This research aims to investigate the effect of reduced graphene oxide (rGO) on the kinetics of addition vulcanization in polydimethylsiloxane (PDMS) elastomers. For this purpose, the synthesis of graphene oxide (GO) and silane‐grafted GO followed by chemical reduction of particles was conducted to prepare rGOs with different surface chemistry. Particles were characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, x‐ray diffraction, scanning electron microscopy, and energy‐dispersive x‐ray analysis. Composites of PDMS containing these particles were prepared by solution mixing, and vulcanization of composites was investigated using differential scanning calorimetry. Results showed that the rate and degree of vulcanization reaction increase up to a critical concentration of particles and then decrease afterward. This behavior was attributed to the catalytic effect of chemical groups on the surface of rGOs, whereas the reverse behavior above the critical concentration was correlated to the immobilization of trapped rubber in the network of particles. Grafting graphene oxide by a long alkyl‐chain silane covered these chemical groups, suppressed the catalytic effect, improved the dispersion of particles, and shifted the critical concentration lower. The critical concentration was correlated to the electrical percolation threshold of particles and confirmed by the solvent swelling method. It was also shown that rGO can itself act as the catalyst for the vulcanization of PDMS with no need for platinum. As the dynamic‐mechanical‐thermal analysis showed, the PDMS composites containing 0.75 wt% of particles did not vulcanize properly. However, composites containing fewer particles were vulcanized. Highlights: Reduced graphene oxide affects additional vulcanization of PDMS.Below a critical loading, rGO accelerates vulcanization by a catalytic effect.Above critical loading, rGO decelerates vulcanization by a networking effect.Surface groups of rGO control catalytic and networking mechanisms.Silane modification of rGO affects interfacial behavior, thus critical loading. [ABSTRACT FROM AUTHOR]

Cellulose nanofibers (CNFs) are part of organic crystallization macromolecular compounds that can be found in bacteria's capsular polysaccharides and plant fibers. CNFs have a lot of potential as suitable matrices and advanced materials, and there have been a lot of studies done on them so far, both in terms of modifying them and inventing uses for them. In this paper, CNFs/reduced graphene oxide (GO) (rGO) nanocomposites were developed to create renewable, flexible, and cheap humidity sensors. The composite film's performance as a humidity sensor was evaluated by analyzing the variations in capacitance at different humidity levels. The synthesized composite film underwent characterization using various analytical techniques, including scanning electron microscopy (SEM), UV (ultraviolet)/Vis (visible) spectrophotometry, Fourier transform infrared spectroscopy (FTIR), and thermomechanical analysis (TMA). The sensing mechanism is elucidated based on hydrophilic functional groups within the composite material. It has been observed that 3 wt% rGO/CNF composite is the best suited for humidity sensing among all other samples. [ABSTRACT FROM AUTHOR]

In this study, a label-free electrochemical aptasensor for sensitive detection of aflatoxin B1 (AFB1) was created by using a glassy carbon electrode (GCE) with polyaniline-functionalized graphene oxide (GO-PANI) and gold nanoparticles (AuNPs). Various spectroscopic techniques such as UV–Vis spectroscopy (UV–vis), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Zeta potential, and Raman spectra were employed to analyze the morphology and composition of the GO-PANI-Au nanocomposite, confirming its successful preparation. This aptasensor could be used for the detection of AFB1 with a broad linear range of 0.0001 to 50 ng/mL and a low limit of detection (LOD) of 0.0377 pg/mL under the optimized conditions. Furthermore, the constructed aptasensor displayed remarkable selectivity, repeatability, and stability. To validate the practical usability of our aptasensor, we successfully tested it on millet and corn samples, yielding a satisfactory recovery rate of 98.87–106.10% for AFB1 detection. This outcome highlights the potential application of our methodology in real sample analysis. A highly efficient and sensitive electrochemical aptamer sensor was successfully developed using GO-PANI-AuNPs nanocomposites, and can be used for the detection of AFB1 with good selectivity, repeatability, and stability. [ABSTRACT FROM AUTHOR]

A novel L-Arginine-copper complex (L-Arg-Cu) was synthesized regarding the necessity for impeding pathogenic microorganisms with no usage of antibiotics. The L-Arg-Cu complex was immobilized onto the graphene oxide surface (GO/L-Arg-Cu). The Fourier transform infrared and Raman spectroscopies, as well as X-ray diffraction, thermogravimetric analysis, field emission scanning electron microscopy, energy-dispersive X-ray (EDX) spectroscopy, were performed to evaluate the chemical interactions and physical properties of the synthesized compound. To achieve better antimicrobial and wound healing properties of electrospun nanofiber (NF) scaffolds, the GO/L-Arg-Cu composite was loaded in polyvinyl alcohol (PVA). It was attempted to improve the stability and mechanical properties of the fabricated NFs via a heat-induced cross-linkage with citric acid (CA). The SEM images analysis revealed the cross-linked PVA/GO/L-Arg-Cu NFs (PVA/GO/L-Arg-Cu/CA NFs) with an average diameter of 167 nm and smooth surface without any beads. Furthermore, EDX spectroscopy and X-ray mapping showed uniform dispersion of GO/L-Arg-Cu in PVA NFs. The hydrophilicity of NFs was studied by measuring water contact angle (WCA) and degree of swelling. The WCA increased from 17° to 46° for the PVA/CA and PVA/GO/L-Arg-Cu/CA NFs, respectively. The antibacterial activity of the synthesized compounds was explored via Agar diffusion well method. Moreover, the inhibitory of the cross-linked PVA/GO/L-Arg-Cu NFs against bacteria causing wound infections was compared with GO, L-Arginine amino acid, CuO nanoparticles, GO/CuO nanocomposite (NC), GO/L-Arg and their nanofiber scaffolds. The PVA/GO/L-Arg-Cu/CA NFs showed the highest inhibitory zone against Escherichia coli (36 ± 0.34 mm) and Pseudomonas aeruginosa (28 ± 0.25 mm). Besides, the MTT assay on human skin fibroblast (HDF) cells related to the incorporation of copper-L-Arginine complex in nanofiber revealed a high cell viability of over 95%. These results indicated that the PVA/GO/L-Arg-Cu NFs based on an N, O-chelating may have potential application in wound healing. [ABSTRACT FROM AUTHOR]

The research aim is to develop pure epoxy composites (PEC), PTL-reinforced epoxy composites (PTLEC), PTL-loaded and E-glass fiber- incorporated epoxy composites (PTLEIEC), and PTL- and E-glass fabric and graphene oxide-incorporated epoxy composites (PTLEIEGO) were fabricated through an open molding hand layup technique, and structural, mechanical, and thermal stability were carried out and results were compared. Functional groups such as OH, -C-H, C=O, C=C, and C-OH, were found in PTL. Similarly, the OH, C-H, Si-O-Si, C=O, and C-H present in the PTLEIEGO composites were found through Fourier transform infrared spectroscopy (FTIR). The crystal plane orientations (110) and (220) in the PTLEIEGO composites were found through XRD. The surface morphology and elemental compositions of PTLEIEGO composites were found through field emissions electron microscopy (FESEM) and found the presence of different organic and inorganic elemental compositions such as C, O, Si, Ca, Zn, K, and Br as 77.85, 20.78, 0.33, 0.45, 0.05, 0.05, and 0.50 wt.% through energy dispersive X-ray (EDX) spectroscopy. The DSC and TGA were carried out and found the thermal stability of the composites and the onset melting temperature was found to 353.1˚ C. The maximum tensile strength of PTL, PEC, PTLEC, PTLEIEC, and PTLEIEGO composites was found to be 1.25 MPa, 25 ± 0.5 MPa, 55 ± 0.5 MPa, 93 ± 0.5 MPa, and 120 ± 0.5 MPa as per ASTM D 638. The tensile strength was improved from 1.25 MPa for PTL to 120 ± 0.5 MPa for PTLEIEGO. The FEM results revealed a minimum error of 0 % and a maximum error of 21.38 % compared to the experimental results. The maximum shore D hardness of PEC, PTLEC, PTLEIEC, and PTLEIEGO composites was found to be 55 ± 0.5 SHN, 59 ± 0.5 SHN, 76.1 ± 0.5 SHN, and 81.4 ± 0.5 SHN, respectively, as per ASTM D2240. The flexural strengths of PEC, PTLEC, PTLEIEC, and PTLEIGO composites were found to be 37 ± 0.5 MPa, 43 ± 0.5 MPa, 94 ± 0.5 MPa, and 131 ± 0.5 MPa, respectively, as per ASTM D 790. The new composites would be employed in low-strength structural applications such as panels, cabins, doors, and laptop stands. The tensile strength of PTL, PEC, PTLEC, PTLEIEC, and PTLEIEGO were found to be 1.25, 25 ± 0.5, 55 ± 0.5, 93 ± 0.5, and 120 ± 0.5 MPa, respectively. The tensile strength of the experimental results was compared with FEM results. The shore D hardness of PEC, PTLEC, PTLEIEC, and PTLEIGO was determined to be 55 ± 0.5, 59 ± 0.5, 76.1 ± 0.5, and 81. 4 ± 0.5 SHN, respectively. The novel composite would be employed in low-strength structural applications such as panels, cabins, doors, and laptop stands. [ABSTRACT FROM AUTHOR]

The utmost dangerous and significant source of environmental contamination is constituted by ionic dyes and heavy metals. Graphene oxide (GO) can eradicate heavy metal ions and dyes from effluent, but the major difficulty associated with GO is the inconvenience during separation. In this study, magnetic reduced GO (rGO-Fe3O4) hybrid nanocomposite is synthesized by using the novel green reducing agent and is used as an adsorbent for the removal of methylene blue (MB) dye and Cd (II) ions. The prepared samples are characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), and FTIR spectroscopy. adsorption study of rGO-Fe3O4 is carried out using UV visible spectrophotometry and it is obtained that the maximum adsorption capacity in the mono component system using double distilled water for MB dye and Cd (II) ions is 64.52 and 93.49mg/g, respectively. Moreover, the effect of different parameters such as temperature, adsorbent dosage, contact time, pH and initial adsorbate concentration on the adsorption of heavy metal and dye is investigated. [ABSTRACT FROM AUTHOR]

Dopamine (3,4‐dihydroxyphenethylamine) (DA) plays an important role in influencing emotions, pleasure sensations, concentration, pain, and coordination of body movements. However, abnormal levels of DA in the brain can lead to Parkinson's, Alzheimer's, or schizophrenia diseases. A biosensor is defined as an analytical tool that combines certain biological recognition components with a physical transducer. A comprehensive study was conducted to enhance the performance of DA detection by incorporating reduced graphene oxide (rGO), polypyrrole (PPy), and nickel oxide (NiO) into the glassy carbon electrode (GCE). DA levels were measured using cyclic voltammetry (CV) with a three‐electrode configuration. Material characterization was evaluated by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The results obtained indicate that PPy/rGO/NiO/GCE has a detection limit of 0.195 mM and a sensitivity of 25.887 A mM−1 cm−2 for a linear range of 0.01–1 mM. [ABSTRACT FROM AUTHOR]

Thin films of polythiophene/graphene oxide (PTh/GO) were prepared using chronoamperometry. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (FESEM), UV-Vis spectroscopy, and photoluminescence spectroscopy (PL) were used for characterization purposes. PTh and PTh/GO thin films were achieved through chronoamperometry at a constant anodic potential of +1.9 V vs. Ag/AgCl. The PTh/GO thin films exhibited visible light absorption. The thicknesses of the thin films were approximately 2.42 μm. [ABSTRACT FROM AUTHOR]

In this study, we explored the behavior of protonated polyaniline/graphene oxide (PANI‐CSA/GO) nanocomposite films with varying GO concentrations, focusing on the novel phenomenon of explosive percolation. We observed a significant increase in electrical conductivity at the explosive percolation threshold, attributed to the emergence of a percolating metallic pathway. This discovery positions PANI‐CSA/GO films as promising materials for various electronic and electrical engineering applications. Additionally, the films demonstrated consistent and repeatable photoconductivity, showing potential for use in high‐performance UV‐photodetectors, photoactive layers in solar cells, light‐emitting diodes, and energy storage devices. Structural analyses using fourier transform infrared spectroscopy (FTIR) and x‐ray diffraction (XRD) confirmed successful GO incorporation within the PANI‐CSA matrix. Different morphological features were observed depending on the GO volume fraction, with increased GO enhancing thermal stability in the conductive zone. Our findings highlight the immense potential of PANI‐CSA/GO nanocomposite films in advanced electronic applications, emphasizing their novel conductive and photoconductive properties and improved thermal stability. [ABSTRACT FROM AUTHOR]

In this study, an innovative conductive hybrid biomaterial was synthetized using collagen (COL) and reduced graphene oxide (rGO) in order for it to be used as a wound dressing. The hydrogels were plasticized with glycerol and enzymatically cross-linked with horseradish peroxidase (HRP). A successful interaction among the components was demonstrated by FTIR, XRD, and XPS. It was demonstrated that increasing the rGO concentration led to higher conductivity and negative charge density values. Moreover, rGO also improved the stability of hydrogels, which was expressed by a reduction in the biodegradation rate. Furthermore, the hydrogel's stability against the enzymatic action of collagenase type I was also strengthened by both the enzymatic cross-linking and the polymerization of dopamine. However, their absorption capacity, reaching values of 215 g/g, indicates the high potential of the hydrogels to absorb fluids. The rise of these properties positively influenced the wound closure process, achieving an 84.5% in vitro closure rate after 48 h. These findings clearly demonstrate that these original composite biomaterials can be a viable choice for wound healing purposes. [ABSTRACT FROM AUTHOR]

The corrosion protection of aluminum alloys is severely compromised by marine environments, demanding the formulation of efficient protective coatings. Epoxy resin, diglycidyl ether of bisphenol A (DGEBA), and curing agent diethylenetriamine (DETA) were used with the mixing ratio of 100:12 to synthesize functionalized SiO2/GO-based composite coatings and investigate the corrosion protection efficacy for aluminum alloy AA6061 in marine environments. To boost the coatings' barrier and anticorrosive attributes, functionalized silica (FSiO2, with 0, 3, 6, 9, 12, and 15 wt%) and graphene oxide (GO) were jointly incorporated into the DGEBA/DETA epoxy-hardener system for producing composite coatings. The functionalization of silica particles using 3-aminopropyl-triethoxysilane and synthesis of GO was successfully carried out, according to the Fourier transform infrared spectroscopy evidence. The structural properties were investigated by X-ray diffraction. The hydrophobicity tests were conducted for the measurement of the contact angles. The highest static contact angle (126° ± 2) and the lowest contact angle (74° ± 1.5) were recorded for the sample EHS9GO2 and AA6061, respectively, which showed that EHS9GO2 coating had the most hydrophobic behavior. An adhesion test (method B, tape test) was performed on prepared coatings to check the quality of adhesion with the substrate aluminum alloy AA6061. The neat epoxy coating (EHS0GO0) displayed a fair adhesion rating of 3B, while EHS9GO2 coating exhibited excellent adhesion (5B) with substrate AA6061. Furthermore, electrochemical impedance spectroscopy and potentiodynamic polarization tests were employed for assessing the electrochemical behavior and anticorrosion performance of the prepared coatings. It was observed from the Bode plot, that the impedance magnitude/modulus for EHS9GO2 at lower frequencies was the highest as compared to other samples during immersion in the artificial seawater. The bare aluminum alloy substrate AA6061 had the highest corrosion rate of value 0.10483 ± 0.00198 mm/year, due to the direct contact with the electrolyte. Moreover, the highest value of Ecorr (356 ± 0.42 mV) and lowest values of Icorr (0.18 ± 0.03µA), βa (48.7 ± 2 mV/decade), and βc (28.8 ± 1 mV/decade) were witnessed for EHS9GO2 coating, showing significant anticorrosion efficiency against the corrosive electrolyte. [ABSTRACT FROM AUTHOR]

A flexible gas sensor based on nanocomposite has been developed and characterized for detecting ammonia gas (NH3) in the atmosphere. This sensor utilizes nanocomposite hydrogels composed of Arabic gum (AG), acrylic acid (AAc), reduced graphene oxide (RGO), and silver nanoparticles (AgNPs). Various techniques, including FTIR (Fourier Transform Infrared Spectroscopy), AFM (Atomic Force Microscopy), XRD (X‐ray Diffraction), SEM (Scanning Electron Microscopy), XRF (X‐ray Fluorescence), TGA (Thermo‐gravimetric Analysis), DSC (Differential Scanning Calorimetry), were used to evaluate the sensor's properties. The nanocomposite hydrogels showed exceptional swelling ability (597 %), advantageous for accommodating gas molecules like NH3. The Polymerization and network formation percentages of 31 % and 56 %, respectively, suggest a robust hydrogel matrix structure. When tested for NH3 gas sensing at room temperature, the RGO/AgNPs/AGPAAc‐hydrogel exhibited high sensitivity and stability compared to other variants across gas concentrations ranging from 0 to 100 ppm. The improved performance of the physiochemical properties of the nanocomposite hydrogels might be attributed to the combined effect of AgNPs and RGO, which likely enhance sensitivity and stability. Selectivity tests conducted for three gases at room temperature revealed that the sensor response was highly selective to NH3 at a concentration of 50 ppm. Furthermore, the sensor demonstrated consistent performance over time. These findings suggest potential applications in environmental monitoring and industrial safety, with the possibility of contributing to advancements in gas sensing technology and addressing environmental and safety concerns. [ABSTRACT FROM AUTHOR]

In the present investigation, a comparison of Graphene Oxide (GO) and Functionalized Multiwalled Carbon Nanotubes (FMWCNTs) incorporated in Pozzolana Portland Cement (PPC) mortar was carried out to find their influence on mechanical and durability properties. It has been observed that Pozzolana Portland Cement Carbon-Based Nano-Composites (PCCNCs) mortar has outstanding mechanical and durability properties. The finding shows that the PPC-1G (0.0015% of GO by weight % of cement) and the PPC-1C (0.0015% of FMWCNTs by weight % of cement) showed the greatest improvement in mechanical and durability performance over the curing period of 90 days (d). When PPC-1G and PPC-1C were compared with the reference (PPC-Control) sample, their compressive strengths increased by 11.67% and 8.73%, respectively. In terms of tensile splitting strength, PPC-1G and PPC-1C had shown a 26.35% and a 20.61% increment, respectively, as compared to PPC-Control. The C-S-H gel grows efficiently in the PCCNCs mortar, as per Powdered X-ray Diffraction (PXRD) data. It is possible to determine the carbonates present in the PCCNCs mortar by using Fourier Transform Infrared Spectroscopy (FT-IR). Furthermore, the microstructural behavior of PCCNCs mortar revealed by the Field Emission-Scanning Electron Microscope (FE-SEM) indicates that the production of ettringite and needle-shaped structures contributes to the enhancement of the mechanical strength and durability properties of the PCCNCs mortar. The research paves the way for incorporating GO and FMWCNTs in cement-based materials. This tremendous advancement holds enormous promise for the advancement of the building and infrastructure sectors. Implementing high-performance mortars has the potential to increase the strength, durability, and sustainability of structures, hence contributing to the development of safer and more resilient built environments. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) donating drugs such as organic nitrates have been used to treat cardiovascular diseases for more than a century. These donors primarily produce NO systemically. It is however sometimes desirable to control the amount, location, and time of NO delivery. We present the design of a novel pH-sensitive NO release system that is achieved by the synthesis of dipeptide diphenylalanine (FF) and graphene oxide (GO) co-assembled hybrid nanosheets (termed as FF@GO) through weak molecular interactions. These hybrid nanosheets were characterised by using X-ray diffraction, Raman spectroscopy, Fourier transform infrared spectroscopy, zeta potential measurements, X-ray photoelectron spectroscopy, scanning and transmission electron microscopies. The weak molecular interactions, which include electrostatic, hydrogen bonding and π-π stacking, are pH sensitive due to the presence of carboxylic acid and amine functionalities on GO and the dipeptide building blocks. Herein, we demonstrate that this formulation can be loaded with NO gas with the dipeptide acting as an arresting agent to inhibit NO burst release at neutral pH; however, at acidic pH it is capable of releasing NO at the rate of up to 0.6 μM per minute, comparable to the amount of NO produced by healthy endothelium. In conclusion, the innovative conjugation of dipeptide with graphene can store and release NO gas under physiologically relevant concentrations in a pH-responsive manner. pH responsive NO-releasing organic-inorganic nanohybrids may prove useful for the treatment of cardiovascular diseases and other pathologies. • NO donors are a mainstay of cardiovascular pharmacology but new ways of delivering NO in a controlled manner is desirable. • Dipeptide and graphene oxide co-assembled hybrid nanosheets exhibit pH-responsive switchable/reversible characteristics. • Delivery of NO gas by co-assembled hybrid nanosheets allows the on-demand release of NO under acidic conditions. • These hybrids could serve as a promising strategy for use in stimuli-responsive systems for the delivery of biomolecules. [ABSTRACT FROM AUTHOR]

Textile-based electrodes are the most important components of wearable and portable supercapacitors. Ti3C2Tx MXene and reduced graphene oxide (rGO) have a great potential for the fabrication of high-performance textile supercapacitor electrodes. In this work, rGO was synthesized with the presence of cellulose nanocrystal (CNC) and Ti3C2Tx/rGO/CNC dispersions with different rGO/CNC contents were prepared. The plain-woven cotton fabrics were coated by homogenous Ti3C2Tx and Ti3C2Tx/rGO/CNC dispersions (5% wt., 15% wt., 30% wt. and 50% wt. rGO/CNC content) and characterized by X-ray Diffraction, Fourier Transform Infrared spectroscopy and Scanning Electron Microscopy techniques. The electrochemical characterization techniques showed that Ti3C2Tx/rGO/CNC loaded fabric electrodes up to 15 wt.% rGO/CNC content exhibited a high specific capacitance of 501.1 F g−1 at a current density of 0.3 A g−1 with low internal electrode resistance, and a good electrochemical stability. The results also showed that MXene/rGO/CNC based high-performance textile supercapacitor electrodes can be prepared by simple drop-casting method. [ABSTRACT FROM AUTHOR]

Graphene has become a prominent material in cancer research in recent years. Graphene and its derivatives also attract attention as carriers in drug delivery systems. In this study, we designed a graphene oxide (GO)-based methotrexate (MTX)-loaded and folic acid (FA)-linked drug delivery system. MTX and FA were bound to GO synthesized from graphite. MTX/FA/GO drug delivery system and system components were characterized using Fourier transform infrared spectroscopy (FTIR), differential calorimetric analysis (DSC), scanning electron microscopy (SEM), transmission electron microscopy (TEM), zeta potential analysis, and dimension measurement (DLS) studies. SEM and TEM images confirmed the nanosheet structure of GO synthesized from graphite, and it was shown that MTX/FA binding to GO transformed the two-dimensional GO into a three-dimensional structure. FTIR and DSC graphs confirmed that oxygen atoms were bound to GO with the formation of carboxylic, hydroxyl, epoxide, and carbonyl groups as a result of the oxidation of graphite, and GO was successfully synthesized. Additionally, these analyses showed that MTX and FA bind physicochemically to the structure of GO. The in vitro Franz diffusion test was performed as a release kinetic test. The release kinetics mathematical model and correlation coefficient (R2) of MTX-loaded GO/FA nanomaterials were found to be the Higuchi model and 0.9785, respectively. Stiffness analyses showed that adding FA to this release system facilitated the entry of the drug into the cell by directing the system to target cells. As a result of the stiffness analyses, the stiffness values of the control cell group, free MTX, and MTX/FA/GO applied cells were measured as 2.34 kPa, 1.87 kPa, and 1.56 kPa, respectively. According to these results, it was seen that MTX/FA/GO weakened the cancer cells. Combined use of the MTX/FA/GO drug delivery system had a higher cytotoxic effect than free MTX on the MDA-MB-231 breast cancer cell line. The results showed that the synthesized MTX/FA/GO material has promising potential in cancer cell-specific targeted therapy for MTX as a drug delivery system. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) has recently attracted attention with its unique chemical and physical properties and serves as a raw material for graphene-based materials. GO has been produced for decades by the Hummers Method with the oxidation process of graphite. The properties and structure of GO are significantly affected by the production parameters of Hummers Method. In this study, the effect of the water content on the oxidation level of GO structure was investigated. GO was produced with different amounts of water in the oxidation stage of Hummers Method. The structural characterizations of produced GO were carried out by X-ray Diffraction Technique (XRD), Fourier Transform Infrared Spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS), Energy Dispersive X-ray Spectroscopy (EDS), UV-Visible Spectroscopy (UV-Vis) and Raman Spectroscopy. Additionally, morphological and thermal characterization of the produced GO samples were performed by Scanning Electron Microscopy (SEM) and Thermogravimetric Analysis (TGA)/Differential Thermal Analysis (DTA), respectively. According to XRD, FTIR, XPS, and EDS results, it was determined that the oxidation degree of GO decreased with increasing amount of water. Besides, it was revealed that the post-oxidation step generated more defects in the basal plane of graphene according to the results of the Raman Analysis. Also, it was observed that GO had a smoother surface and was found to have higher thermal stability with increasing amounts of water. The results show that the post-oxidation step reduces the oxidation degree of GO, increases the amount of the defect, provides a less wrinkled structure, and improves the thermal stability of GO. [ABSTRACT FROM AUTHOR]

In this study, the electrocatalytic activity of the functionalized graphene oxide (GO) using L-lysine (GO-Lys) as well as L-lysine and copper (GO-Lys-Cu) was investigated for oxygen and hydrogen evolution reactions. Identification and characterization of GO, GOLys and GO-Lys-Cu were done using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, field emission scanning electron microscopy (FESEM) and elemental mapping images. Also, electrochemical impedance spectroscopy (EIS) and linear sweep voltammetry (LSV) were used to investigate the electrochemical properties and electrocatalytic activities. The obtained results not only confirmed the decoration of the GO surface by Lys and Lys-Cu, but also revealed the reduction of graphene oxide (rGO) sheets. EIS results confirmed the lowest charge transfer resistance for Lys-rGO hybrid nanocomposite compared to other synthesized samples. The results obtained of LSV show that the functionalization of GO with Lys-Cu leads to efficient and stable electrocatalytic activity for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) with the lowest overpotential (375 and 732 mV, respectively) at the current density of 10 mA/cm2 (1 M KOH) and the smallest Tafel slope is 346 and 160 mV/dec, respectively, compared to GO, L-Lys, GO-Lys and Lys-Cu samples. [ABSTRACT FROM AUTHOR]

Despite the significant Progression in nanocomposites (NCs) tailoring for ecological purposes, optimizing NCs for water treatment is still a challenge. Moreover, organic coloring (dyes) agents like Congo red (CR) and methylene blue (MB) were included which have carcinogenic effects. In this regard, photo-catalytic activity utilizing NCs for organic pollutants (dyes) removal is a great concern due to its viability and low cost. In this regard, a combination of nanocomposites including cerium Oxide (CeO 2), gadolinium oxide (Gd 2 O 3), and graphene oxide (GO) could be suggested. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) were utilized for characterization in addition to EDX, and electron microscopes (TEM, and FESEM). TEM micrograph exhibits TNC as scattered lanthanides oxides (CeO 2 , and Gd 2 O 3) grains upon GO sheets. It shows a clear decline in the average size to reach 25 nm for CeO 2 , and 40 nm for Gd 2 O 3. Also, FESEM reports that GO reduces the lanthanide oxides aggregation tendency in TNC, besides forming shallow pores within its rough surface. Regarding the thermal study, It is clear that activation energy (E*) is the almost equal enthalpy of activation (ΔH). It could refer to the presence of the tested composition at a higher degree of temperature (thermally stable). Nano-composite powders exhibited improvement in photo-catalytic efficiency and inhibition of photo-corrosion as compared with pure lanthanide oxides. The MB degradation potential of CeO 2 /Gd 2 O 3 /GO drops from 94.4 % in the first usage to 82.1 % in the fifth. [Display omitted] [ABSTRACT FROM AUTHOR]

Graphene oxide/polyimide nanocomposites, expect that these properties increase. That's why by the incorporation of modified graphene oxide into polyimides, graphene oxide polyimide nanocomposite can be achieved with excellent properties as compared to the parent material and may perform better than polyimide in different applications like in batteries and nano-platelet fillers etc. The aim of this research project is to enhance the thermal conductivity of graphene oxide (GO)/PI nanocomposite films. These polyimide nanocomposite films will be analyzed and characterized using X-rays diffractions (XRD), Fourier transform infrared spectroscopy (FTIR). We will measure the thermal stability of polyimide nanocomposites films by using gravimetric analysis (TGA). [ABSTRACT FROM AUTHOR]

In this project, a nanosorbent was prepared using graphene oxide nanosheets modified with a specific mercury aptamer to detect very low mercury concentrations in aqueous solutions. The properties of the prepared nanosheets as adsorbents in the adsorption of mercury cations by microextraction in a packed syringe and analysis with a spectrophotometer were evaluated. Scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray energy diffraction were used to characterize the nanosheets obtained. The optimization conditions affecting the extraction and determination of mercury by spectrophotometry such as the influence of the pH of the aqueous solution, the number of sample loading times, the number of desorption times, the contact time of the analyte with the adsorbent, the amount of adsorbent and the volume of wash solvent were investigated. Under optimization conditions, the calibration curve of the method was linear between 20 and 800 μg L−1, and the detection limit of the method was 2.2 μg L−1. Mercury analysis in real samples such as Gavoshan dam water, Gamasiab river water and Bashir Taq Bostan spring water was also investigated to evaluate the method. [ABSTRACT FROM AUTHOR]

Cadmium (Cd), a heavy metal that is very harmful to both the environment and human health, makes it difficult to detect in environmental and analytical research. However, given the adverse impacts, a remedy is urgently required. Due to its special benefits, electrochemical approaches have recently attracted a lot of interest for the detection of Cd(II) ions. We have prepared zinc selenide/graphene oxide (ZnSe/GO) nanocomposites and characterized its structural, compositional, and morphological properties using X-ray diffraction, elemental mapping, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy, to fabricate an efficient electron mediator for electrochemical sensor. Results of the experiments proved that the device is reliable in Cd(II) detection with 45.54 µM limit of detection (LOD) and 138.00 µM limit of quantification (LOQ). The sensor showed a linear range of output current at 100–700 µM Cd(II) with the coefficient of correlation (R2 = 0.996). Interferents have a negligible effect on the response of the sensor. [ABSTRACT FROM AUTHOR]

Polyester‐urea coatings were synthesized from corn oil with the help of a series of reactions in three different compositions by varying the amount of urea. Out of all the synthesized compositions, the best composition was optimized based on various parameters. The optimized composition was used as a matrix and graphene oxide (GO) was incorporated in three ratios, for the formulation of corn oil‐based CPEUr@GO nanocomposites. Fourier transform infrared spectroscopy was used to confirm all the reactions. The physico‐mechanical properties of CPEUr2 coating were found to be the best among all the compositions. Therefore, CPEUr2 was selected as a matrix for the inclusion of GO nanosheets to prepare CPEUr2@GO nanocomposites. Thermogravimetric analysis results showed that incorporation of GO enhanced the thermal stability of CPEUr2 up to 325°C. The anticorrosive studies revealed the high impedance value of 6.5 × 105 Ω.cm2 in case of CPEUr2@GO0.5. Furthermore, it can be concluded that the inclusion of 0.5 wt% GO proved to be the optimized amount to produce sustainable CPEUr2 coatings with good performance. These CPEUr@GO nanocomposite coatings can be used for various protective purposes owing to their excellent physico‐mechanical thermal as well as anticorrosive performance. Highlights: Corn oil‐based polyester‐urea, CPEUr, coatings were synthesized in three different compositions.The best composition was used as a matrix for the formulation of CPEUr@GO nanocomposites.Graphene oxide of 0.5 wt% was found to be the optimum quantity required to modify CPEUr matrix.Thermal stability, mechanical durability as well as corrosion resistance performances were enhanced.The environment friendly approach is suitable for the development of corrosion protective coatings. [ABSTRACT FROM AUTHOR]

In this study, we used multilayer graphene oxide (GO) obtained by anodic oxidation of graphite powder in 83% sulfuric acid. The modification of GO was carried out by its interaction with hexamethylenediamine (HMDA) according to the mechanism of nucleophilic substitution between the amino group of HMDA (HMDA) and the epoxy groups of GO, accompanied by partial reduction of multilayer GO and an increase in the deformation of the carbon layers. The structure and properties of modified HMDA-GO were characterized using research methods such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy and Raman spectroscopy. The conducted studies show the effectiveness of using HMDA-OG for modifying epoxy composites. Functionalizing treatment of GO particles helps reduce the free surface energy at the polymer–nanofiller interface and increase adhesion, which leads to the improvement in physical and mechanical characteristics of the composite material. The results demonstrate an increase in the strength and elastic modulus in bending by 48% and 102%, respectively, an increase in the impact strength by 122%, and an increase in the strength and elastic modulus in tension by 82% and 47%, respectively, as compared to the pristine epoxy composite which did not contain GO-HMDA. It has been found that the addition of GO-HMDA into the epoxy composition initiates the polymerization process due to the participation of reactive amino groups in the polymerization reaction, and also provides an increase in the thermal stability of epoxy nanocomposites. [ABSTRACT FROM AUTHOR]

This study evaluated the mechanical properties and the chemical and thermal characteristics of low-density polyethylene (LDPE) nanocomposites reinforced with graphene oxide for manufacturing via 3D printing. LDPE nanocomposites with different graphene oxide (GO) loadings (0.5% and 1.5%) were processed by a single-screw extruder. To characterize the pre-injected material, Fourier transform infrared spectroscopy (FTIR) and thermal characterization with thermogravimetry (TGA) were used. The injected material was also characterized with mechanical impact and traction tests. The results showed that incorporating GO into the polymeric matrix added hydroxyl groups to the matrix structure, with a 39.13% increase in Young's modulus for LDPE-1.5%wtGO samples. Mechanical tests of 3D printed samples showed that, with an increase in the amount of GO in the polymer matrix, the composite loses ductility, enabling its use in 3D printing technologies and thus encouraging new studies on printed materials for various applications. [ABSTRACT FROM AUTHOR]

In this study, a method for producing nitrogen-modified graphene oxide (NMGO) using hydrothermal synthesis in the presence of triethanolamine is presented. The composition and structure of NMGO are characterized using X-ray phase analysis (XPA), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy, and Raman spectroscopy. Ni-based metal matrix coatings (MMCs) modified with NMGO were obtained from a sulfate-chloride electrolyte in the galvanostatic mode. The process of electrochemical deposition of these coatings was studied using chronovoltammetry. The microstructure of Ni–NMGO MMCs was studied using the XPA and SEM methods. It has been established that the addition of NMGO particles into the Ni matrix results in an increase in the microhardness of the resulting coatings by an average of 1.30 times. This effect is a consequence of the refinement of crystallites and high mechanical properties of NMGO phase. The corrosion-electrochemical behavior of studied electrochemical deposits in 0.5 M sulfuric acid was analyzed. It has been shown that the corrosion rate of Ni–NMGO MMCs in a 3.5% sodium chloride environment decreases by approximately 1.50–1.70 times as compared to unmodified Ni coatings. This is due to NMGO particles that act as a barrier preventing the propagation of the corrosion and form corrosive galvanic microelements with Ni, promoting anodic polarization. [ABSTRACT FROM AUTHOR]

This work investigates the photocatalytic performance of V2O5 and V3O7 nanoparticles and their nanocomposites with rGO. The as-annealed V2O5 and V3O7 nanoparticles exhibited pure orthorhombic and monoclinic structures with an optical bandgap of 2.3 and 2.5 eV, respectively. The corresponding vibrational modes using Raman and FTIR spectroscopy analysis further confirm the form. The morphological studies reveal that V2O5 and V3O7 nanoparticles possess plate and petal-like morphology, respectively. Moreover, in the case of V2O5/V3O7—rGO nanocomposites, the plate/petal-like nanoparticles are embedded within rGO sheets. Incorporating nanoparticles within rGO sheets has quenched the green photoluminescence emission, enhancing their photocatalytic performance upon irradiation with white light of 100 mW/cm2. This is ascribed to the effective transport of interfacial electrons from vanadium oxide nanoparticles to the rGO surface, reducing the recombination of photogenerated charge carriers. These results indicate that the vanadium oxide/rGO nanocomposites have potential applications in wastewater treatment. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have been widely studied in photocatalytic CO2 reduction reaction (CO2RR). However, pristine COFs usually exhibit low catalytic efficiency owing to the fast recombination of photogenerated electrons and holes. In this study, we fabricated a stable COF‐based composite (GO‐COF‐366‐Co) by covalently anchoring COF‐366‐Co on the surface of graphene oxide (GO) for the photocatalytic CO2 reduction. Interestingly, in absolute acetonitrile (CH3CN), GO‐COF‐366‐Co shows a high selectivity of 94.4 % for the photoreduction of CO2 to formate, with a formate yield of 15.8 mmol/g, which is approximately four times higher than that using the pristine COF‐366‐Co. By contrast, in CH3CN/H2O (v : v=4 : 1), the main product for the photocatalytic CO2 reduction over GO‐COF‐366‐Co is CO (96.1 %), with a CO yield as high as 52.2 mmol/g, which is also approximately four times higher than that using the pristine COF‐366‐Co. Photoelectrochemical experiments demonstrate the covalent bonding of COF‐366‐Co and GO to form the GO‐COF‐366‐Co composite facilitates charge separation and transfer significantly, thereby accounting for the enhanced catalytic activity. In addition, theoretical calculations and in situ Fourier transform infrared spectroscopy reveal H2O can stabilize the *COOH intermediate to further form a *CO intermediate via O−H(aq)⋅⋅⋅O(*COOH) hydrogen bonding, thus explaining the regulated photocatalytic performance. [ABSTRACT FROM AUTHOR]

The aim of this study was to synthesize and characterize Cellulose Acetate (CA) porous scaffolds using the electrospinning technique associated with Hydroxyapatite (HA) and different concentrations of graphene oxide (GO), for advanced regenerative therapies application. The scaffolds were categorized into four distinct groups based on their composition: (1) Pure CA scaffolds; (2) CAHA scaffolds; (3) CAHAGO 1.0% scaffolds; (4) CAHAGO 1.5% scaffolds. Transmission Electron Microscopy (TEM) was used for the characterization of the nanocomposite. The scaffolds were analyzed by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS), and in vitro cell viability assays (WST). For the biological test analysis of Variance (two-way) was used, followed by Tukey's post-test (α = 0.05). The TEM analysis allowed for the visualization of the deposition of HA on the graphene sheets, confirming the synthesis of the nanocomposite. XRD revealed the predominant presence of CaP phases in the CAHA, CAHAGO 1.0%, and CAHAGO 1.5% groups, underscoring the inherent mineral composition of the scaffolds. FTIR demonstrated cellulose characteristics and PO4 bands in the groups containing HA, confirming the effective incorporation of this material. Raman spectroscopy revealed distinct peaks in the GO groups, conclusively verifying the successful integration of graphene into the scaffold matrix. The micrographs showcased irregular pores filling the entire surface, arising from the intricate overlapping of fibers during scaffold formation. Importantly, all scaffolds exhibited excellent cell viability in the conducted assays. A proliferation process was observed in CAHA and CAHAGO 1.5% groups after 48 h (p < 0.05). In conclusion, the scaffolds synthesized hold significant promise in the realm of tissue engineering and provide a fresh perspective on the possibilities for regenerative therapies. [ABSTRACT FROM AUTHOR]

Waterborne epoxy (WEP) coatings with enhanced corrosion resistance were prepared using graphene oxide (GO) that was obtained from kish graphite, and amino-functionalized graphene oxide (AGO) was modified by 2-aminomalonamide. The structural characteristics of the GO and AGO were analyzed using X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). And the anti-corrosive performance of waterborne epoxy-cased composite coatings with different addition amounts of AGO was investigated using electrochemical measurements, pull-off adhesion tests, and salt spray tests. The results indicate that AGO15/WEP with 0.15 wt.% of AGO has the best anti-corrosive performance, and the lowest frequency impedance modulus increased from 1.03 × 108 to 1.63 × 1010 ohm·cm−2 compared to that of WEP. Furthermore, AGO15/WEP also demonstrates the minimal corrosion products or bubbles in the salt spray test for 200 h, affirming its exceptional long-term corrosion protection capability. [ABSTRACT FROM AUTHOR]

The toxic and the hazardous ramifications that affect both the environment and human beings due to the existence of uranium in wastewater are a huge challenge towards a sustainable environment. Uranium removal from wastewater is a big difficulty that is becoming more severe as the world's population grows and energy demand rises. A hydrothermal and freeze-drying process is used to create a chitosan/graphene oxide/poly (vinyl alcohol) aerogel (CH/GO/PVA) for a very effective and selective uranium removal. Batch experiments were used to examine hexavalent uranium (VI) sorption from wastewater. The efficiency of U (VI) removal was investigated for time of contact, various pH, dosage of sorbent, initial concentration of U (VI), and temperature values. Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, Energy Dispersive Spectroscopy, X-ray diffraction, and Brunauer-Emmett-Teller are utilized to describe the composition, morphology, polymer formation and nanocomposites. Kinetic and Freundlich equations, and the pseudo-second-order are used to illustrate the adsorption process. The adsorption capacity of U (VI) reaches its maximum of 1247 mg g–1 when an initial uranium concentration is 380 mg L–1, and the highest uranium removal efficiency is 98.44%. Thermodynamic study reveals an endothermic and spontaneous adsorption mechanism. Furthermore, the as-synthesized GO/CS/PVA aerogel has good mechanical as well as thermal stability, and can be utilized six times before losing a substantial portion of its original removing effectiveness. [ABSTRACT FROM AUTHOR]