Designing an epoxy composite coating having dual-barrier-active self-healing anti-corrosion functions using a multi-functional GO/PDA/MO nano-hybrid

The graphene oxide, functionalized with polydopamine (PDA) bio-polymers and molybdate (MO) ions, was incorporated into the epoxy coating. The FT-IR, Raman, UV-visible, XRD, and FE-SEM/EDS analyses were utilized for the GO/PDA/MO nanoparticle characterization. The sequence of inhibitors' release from the nano-hybrid and their effect on the electrochemical behavior of the steel sample was explored by the OCP, polarization, and, EIS analyses in the aquatic saline media. EIS analyses revealed inhibition efficiency of 88% for the sample immersed in the GO/PDA/MO-contained solution after 48 h immersion. The polarization results showed a 91% corrosion mitigation index for the sample submerged in the GO/PDA/MO extract-containing solution after 48 h immersion. An increase of the scratched coating Nyquist diameter, the lower corrosion product, and coating blister formation after exposure to the salt spray chamber, as well as the lower adhesion loss in the pull-off test (26%), revealed that the epoxy coating reinforced with GO/PDA/MO nano-hybrids could mitigate the mild steel corrosion by improving the barrier performance and active corrosion protection (self-healing mechanism) behavior.     

EMI shielding performance of electroless coated iron nanoparticles on graphite in low-density polyethylene composite for X-band applications

In the proposed work, an investigation of shielding effectiveness (SE) for varying compositions of Graphene, Multiwall carbon nanotubes (MWCNT), and Iron nanoparticles coated on Graphite (Fe@Graphite) was conducted in X-band (8.2 GHz–12.4 GHz). All these are mixed in an LDPE matrix. The nanomaterial was subjected to chemical characterization, i.e., Scanning electron microscopy (SEM), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM). The shielding observed is dominantly due to absorption. The lattice structure which facilitates the shielding due to absorption was the hexagonal graphite structure on whose surface iron nanoparticles were embedded and used as the magnetic filler. At the same time, Graphene and MWCNT act as electrically conducting fillers. The Total shielding effectiveness(SE_T) was maximum for LDPE, MWCNT, Graphene, and Fe@Graphite, in the ratio of 50: 5: 25: 20 by weight %, and is 49 dB at 9.65 GHz for a sample thickness of 3 mm.     

Inlaying Bismuth Nanoparticles on Graphene Nanosheets by Chemical Bond for Ultralong-Lifespan Aqueous Sodium Storage

Rechargeable aqueous sodium ion batteries (ASIBs) are rising as an important alternative to lithium ion batteries, owing to their safety and low cost. Metal anodes show a high theoretical capacity and nonselective hydrated ion insertion for ASIBs, yet their large volume expansion and sluggish reaction kinetics resulted in poor electrochemical stability. Herein, we demonstrate an electrode cyclability enhancement mechanism by inlaying bismuth (Bi) nanoparticles on graphene nanosheets through chemical bond, which is achieved by a unique laser induced compounding method. This anchored metal-graphene heterostructure can effectively mitigate volume variation, and accelerate the kinetic capability as the active Bi can be exposed to the electrolyte. Our method can achieve a reversible capacity of 122 mAh g⁻¹ at a large current density of 4 A g⁻¹ for over 9500 cycles. This finding offers a desirable structural design of other metal anodes for aqueous energy storage systems.     

One-pot synthesis of CoO–ZnO/rGO supported on Ni foam for high-performance hybrid supercapacitor with greatly enhanced cycling stability

The high specific capacitance along with good cycling stability are crucial for practical applications of supercapacitors,which always demands high-performance and stable electrode materials.In this work,we report a series of ternary composites of CoO-ZnO with different fractions of reduced graphene oxide(rGO) synthesized by in-situ growth on nickel foam,named as CZG-1,2 and 3,respectively.This sort of binder-free electrodes presents excellent electrochemical properties as well as large capacitance due to their low electrical resistance and high oxygen vacancies.Particularly,the sample of CZG-2(CoO-ZnO/rGO 20 mg) in a nanoreticular structure shows the best electrochemical performance with a maximum specific capacitance of 1951.8 F/g(216.9 mAh/g) at a current intensity of 1 A/g.The CZG-2-based hybrid supercapacitor delivers a high energy density up to 45.9 Wh/kg at a high power density of 800 W/kg,and kept the capacitance retention of 90.1% over 5000 charge-discharge cycles.     

Preparation of quaternarized N-halamine-grafted graphene oxide nanocomposites and synergetic antibacterial properties

At present, frequent outbreaks of bacteria and viruses have seriously affected people's normal lives. Therefore, the study of broad-spectrum antibacterial nanocomposites is very promising. However, most antibacterial materials have some disadvantages, such as single bactericidal mechanisms and unrepeatable use. Based on the current situation, a kind of nanocomposite with three structures of graphene oxide (GO), quaternary ammonium salt (QAs) and N-halamine was prepared, which showed synergistic effect to improve antibacterial activity and combined with a variety of sterilization mechanisms. Meanwhile, GO can provide richer ways of sterilization and high specific surface area, which is conducive to the grafting of quaternarized N-halamine. The advantages of physical sterilization of GO, charge adsorption of QAs, reuse of N-halamine and efficient sterilization are fully utilized. The results showed that the quaternarized N-halamine-grafted GO was obtained successfully. GO grafted with quaternarized N-halamine polymer showed strong speedy bactericidal activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) (99%). It had good storage and regeneration properties.     

Surface oxidized iron-nickel nanorods anchoring on graphene architectures for oxygen evolution reaction

Surface oxidized iron-nickel nanorods coupling with reduced graphene architectures (FeNi-O-rGA) are successfully constructed via hydrothermal, freeze-drying, and thermal activation approaches. The hierarchical structure can provide lots of pathways for fast ion diffusion and charge transfer, and expose abundant catalytic sites. Meanwhile, the activity of FeNi-O-rGA is boosted by the optimized metal-oxygen bond strength in FeNi₃ alloys. Partial oxidized FeNi nanorods are strongly coupled with rGA by the formation of metal-O-C bonds, which can impede the aggregation of FeNi₃ alloys and increase the utilization of active sites. The special structure and partially oxidized FeNi nanorods for FeNi-O-rGA can result in excellent OER activity and catalytic stability. Only 215 mV of overpotential is required to drive the current density of 10 mA/cm² as well as the Tafel slope of 50.9 mV/dec in 1 mol/L KOH. The change of surface chemistry of FeNi-O-rGA is confirmed by XPS after the OER test, which indicates the highly catalytic stability of FeNi-O-rGA due to the formation of intermediate metal oxyhydroxide.     

Recent developments in the adsorptive removal of heavy metal ions using metal-organic frameworks and graphene-based adsorbents

Clean and potable water is a growing concern around the globe. Among the different water pollutants, heavy metal ions pose a serious health concern to all living beings. The quest for new adsorbents to remove heavy metal ions received a boost with the development in the field of metal-organic framework (MOF). The advancement in synthetic strategies and designing of MOF enabled the researchers to tune the adsorption characteristics and tailor the material specific to a heavy metal ion. Similar to MOF, graphene-based two-dimensional and three-dimensional materials are also promising due to the diverse functionalization possibilities and cost-effectiveness. There had been growing interest in applying MOF and graphene-based materials for the removal of heavy metal ions in the past decade. This review summarizes these developments in detail.     

Graphene oxide-octadecylsilane incorporated monolithic nano-columns with 50 μm id and 100 μm id for small molecule and protein separation by nano-liquid chromatography

In this study, graphene oxide-octadecylsilane incorporated monolithic nano-columns were developed for protein analysis by nano liquid chromatography (nano LC). The monolithic column with 100 μm id was first prepared by an in situ polymerization using ethylene dimethacrylate (EDMA), 3-chloro-2-hydroxypropylmethacrylate (HPMA-Cl), and methacryloyl graphene oxide nanoparticles (MGONPs). MGONPs were synthesized by the treatment of 3-(trimethoxysilyl)propylmethacrylate (TMSPM) and GO. Tetrahydrofuran (THF) and dodecanol were used as the porogenic solvent. The resulting column was functionalized by dimethyloctadecylch lorosilane (DODCS) for the enhancement of hydrophobicity. The functionalization greatly improved the baseline separation of hydrophobic compounds such as polyaromatic hydrocarbons (PAHs). The optimized monolith with respect to total polymerization mixture was characterized by using Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) X-ray diffraction (XRD) and chromatographic analyses. The blank monoliths without functionalization exhibited poor separation while a good separation performance of MGONPs functionalized monoliths was achieved. The monolith with 100 μm id was evaluated in protein separation in nano LC using RNase A, Cytochrome C, Lysozyme, Trypsin, and Ca isozyme II as the test proteins. It was shown that protein separation mechanism was based on large π-system of GO and hydrophobicity of the monolithic structure. Theoretical plates number up to 57 600 plates were achieved. The nano-column with 50 μm id was also prepared using the same polymerization mixture under the same chemical conditions. These nano-columns were employed for protein separation by nano LC, and the dependence of both nano-column performance on the internal diameter was also discussed.     

Determination of Tedizolid Phosphate Using Graphene Nanocomposite Based Solid Contact Ion Selective Electrode; Green Profile Assessment by Eco-scale and GAPI Approach

Antibiotics determination plays a major role in minimizing antimicrobial resistance starting from quality control of pharmaceutical formulations to therapeutic drug monitoring. Green modified glassy carbon electrode has been developed for determination of tedizolid phosphate; new antibiotic prodrug; in presence of its active metabolite. The graphene transducer interlayer, dispersed with PVC, improved the electrode stability and standard potential reproducibility. Graphene hydrophobicity prevented the water layer formation between the sensing layers that decreased the potential drift down to 267 μV h⁻¹. Electrochemical impedance showed a low resistance value for graphene containing sensor due to its high electron transfer ability.     

Binary Metal Oxide Adsorbed Graphene Modified Glassy Carbon Electrode for Detection of Riboflavin

Tungsten oxide (W) decorated titanium oxide (T) adsorbed onto a graphene (Gr) and modified the glassy carbon electrode for the electrochemical quantification of riboflavin (RF) in edible food and pharmaceuticals. For comparison, nanocomposites are formed using graphene oxide (GO), reduced graphene oxide (rGO) and pure graphite (G) sheets to study the electrochemical activities towards riboflavin. The ternary WTGr modified GCE shows the highest electrocatalytic activity due to synergetic interactions between the metal oxide and graphene. The electrochemical observations are supported by the SEM, HRTEM, XRD, UV-Vis, Zeta potential (ζ) and size data. The sensor shows a wide linear range 20 nM–2.5 μM with a detection limit 25.24 nM and sensitivity (4.249×10⁻⁸ A/nM). The fabricated sensor is validated in real samples.