Three-dimensional Graphene Oxide Research Articles

Three-Dimensional Graphene Oxide Skeleton Guided Poly(acrylic Acid) Composite Hydrogel Particles with Hierarchical Pore Structure for Hemoperfusion.

Recently, in order to increase and improve treatment efficacy of hemoperfusion, research and development of novel adsorbents have been paid much attention. Herein, three-dimensional (3D) graphene oxide (GO) skeleton guided poly(acrylic acid) (PAA) composite hydrogel particles (HPs) used for hemoperfusion were prepared by a core-shell template method. The 3D GO skeletons with millimeter-scale were first constructed with the assistance of templates, dissolvable poly(ether sulfone) hollow particles, which were prepared by a phase inversion technique; then, PAA hydrogels were formed and distributed on the surface of the 3D GO skeleton. The obtained HPs showed a special hierarchical pore microstructure, small size, and uniform spherical shape. Compared with pure PAA hydrogels, the swelling ratios of the HPs were significantly restricted, and the porosities were remarkably increased; the compressive stress and the elongation at break were improved at the same time. The hemocompatibility tests, including protein adsorption, hemolysis ratio, complement and contact activation, platelet adhesion, and clotting time, were carried out, and the results indicated that the HPs showed good hemocompatibility. The adsorption results indicated that the HPs exhibited good removal efficiency toward exogenous and endogenous toxins. In general, the suitable physical and mechanical properties and the excellent hemocompatibility and adsorption capacities made the composite hydrogel particle a promising candidate for novel hemoperfusion adsorbents.

Facile assembly of three-dimensional cylindrical egg white embedded graphene oxide composite with good reusability for aqueous adsorption of rare earth elements

A porous three-dimensional (3D) macrostructure was facilely fabricated by embedding egg white (EW) into graphene oxide (GO) (CEG) under hydrothermal condition. The microstructure, pore size distribution and surface compositions of CEG were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) method, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopy. The as-prepared 3D CEG composite was used for the aqueous adsorption of rare earth elements (REEs) including La(III), Y(III), Yb(III), Er(III) and Nd(III) from aqueous solutions. The condition parameters such as contact time, initial REEs concentration, pH values and adsorption temperature were investigated. The adsorption could achieve equilibrium within 90 min and the adsorption of REEs onto 3D CEG1:1 composite fitted well to the pseudo second-order kinetics model and the Langmuir isotherm model. Thermodynamic and kinetic studies indicated that the adsorption process was endothermic and spontaneous in nature. The maximum adsorption capacities of 3D CEG1:1 composite were 42.80, 32.16, 56.44, 51.44 and 50.16 mg g−1 toward La(III), Y(III), Yb(III), Er(III) and Nd(III), respectively. The 3D CEG1:1 composite was used to remove the La(III), Y(III), Yb(III), Er(III) and Nd(III) from Yudai river water, Xiangjiang river water, spring water and tap water with spiked recoveries in the range 62.6–99.6%. The 3D CEG1:1 composite showed a good adsorption-desorption ability, and the percentage removal of 3D CEG1:1 composite for Yb(III) remained constant of 100% at a low Yb(III) concentration even after five cycles.

Polyurethane-Supported Graphene Oxide Foam Functionalized with Carbon Dots and TiO2 Particles for Photocatalytic Degradation of Dyes

The design and optimal synthesis of functional nanomaterials can meet the requirements of energy and environmental science. As a typical photocatalyst, TiO2 can be used to degrade dyes into non-toxic substances. In this work, we demonstrated the in-situ hydrothermal synthesis of carbon quantum dots (CQDs)-modified TiO2 (CQDs/TiO2) particles, and the subsequent fabrication of three-dimensional (3D) graphene oxide (GO) foam doped with CQDs/TiO2 via a facile strategy. By making full use of the up-conversion characteristics of CQDs, the synthesized CQDs/TiO2 exhibited high catalytic activity under visible light. In order to recover the photocatalyst conveniently, CQDs/TiO2 and GO were mixed by ultrasound and loaded on 3D polyurethane foam (PUF) by the multiple impregnation method. It was found that GO, CQDs/TiO2, and PUF reveal synergistic effects on the dye adsorption and photocatalytic degradation processes. The fabricated 3D CQDs/TiO2/GO foam system with a stable structure can maintain a high photocatalytic degradation efficiency after using at least five times. It is expected that the fabricated 3D materials will have potential applications in the fields of oil water separation, the removal of oils, and the photothermal desalination of seawater.

Three-dimensional nitrogen-doped holey graphene and transition metal oxide composites for sodium-ion batteries

The unique macroporous architecture in combination with the presence of nanopores in graphene sheets facilitate ion transport during charge/discharge.

One-Pot Transformation of Waste Toner Powder into 3D Graphene Oxide Hydrogel

Waste toner powder is considered not only a recyclable resource but also a hazardous material, because it has a unique microstructure and complex compositions, so it should be properly and effectively disposed of. Herein, we selected waste toner powder as a precursor to synthesize a three-dimensional (3D) porous graphene oxide (GO) hydrogel by a one-pot transformation based on the improved Hummers’ method. A series of detection equipment such as a scanning electron microscope and a Raman spectrometer can be employed to probe the microstructure and formation mechanism of the 3D GO hydrogel. Our experimental results show that a 3D porous GO hydrogel with its excellent microstructure can be prepared by using waste toner powder as the precursor. It provides an effective way to dispose of waste toner powder for functional applications.

Facile synthesis of a novel flower-like BiFeO3 microspheres/graphene with superior electromagnetic wave absorption performances

In recent years, porous or layered magnetic materials have received increasing attention due to their low density and lightweight. In this work, porous BiFeO3 microspheres and three-dimensional porous BiFeO3 microsphere-reduced graphene oxide (RGO) composite (3D porous BiFeO3/RGO) were prepared by one-step etching processing using pure BiFeO3 particles as precursors. The precursor undergoes dissolution-recrystallization/reduction process, resulting in large amount of BiFeO3 fragments and graphene hybrid product, which forms 3D porous BiFeO3/RGO composite. Electromagnetic (EM) absorption performance measurements exhibit that at low thickness of 1.8 mm, porous BiFeO3/RGO composite can achieve reflection loss (RL) value up to −46.7 dB and absorption bandwidth (defined by RL <−10 dB) exceeding 4.7 GHz (from 12.0 to 16.7 GHz), testifying outstanding microwave absorbing performance. Compared with pure porous BiFeO3, improved EM wave absorption ability of as-prepared porous BiFeO3/RGO composite is attributed to interfacial polarization, multiple reflections, scattering, and appropriate impedance matching.

Electrochemiluminescent aptasensor for thrombin using nitrogen-doped graphene quantum dots.

An electrochemiluminescent (ECL) aptamer based method is described for the determination of thrombin. Three-dimensional nitrogen-doped graphene oxide (3D-NGO) was placed on a glassy carbon electrode (GCE) to provide an electrode surface that displays excellent electrical conductivity and acts as a strong emitter of ECL. The modified electrode was further coated with chitosan via electrodeposition. Finally, the amino-modified aptamer was immobilized on the modified GCE. The interaction between thrombin and aptamer results in a decrease in ECL. The assay has a linear response in the 1 fM to 1nM thrombin concentration range and a 0.25 fM lower detection limit (at an S/N ratio of 3). The method was applied to the determination of thrombin in spiked human plasma samples, and recoveries ranged between 94 and 105% (with RSDs of <3.6%).The calibration plot was recorded at potential and wavelength of fluorescence emission (wavelength: 445nm; potential: 0 to -2V). Graphical abstract A bare glassy carbon electrode (GCE) does not display electrochemiluminescence (ECL). If, however, nitrogen-doped graphene quantum dots,chitosan, andthree-dimensional nitrogen-doped graphene oxide (NGQD-chitosan/3D-NGO) are electrodeposited on the GCE, strongECL can be observed. The ECL intensity decreased after aptamer and bovine serum albumin (BSA) were dropped onto the electrode (curve a). However, the ECL further decreases after addition of thrombin (TB;curve b).

Three-dimensional graphene oxide foams loaded with AuPd alloy: a sensitive electrochemical sensor for dopamine.

The authors describe a chemical sensor for dopamine (DA). It is based on the use of three-dimensional graphene oxide (3D rGO) loaded with varying amounts of AuPd bimetallic nanoparticles (3D rGO/AuPd NPs). The 3D rGO acts as an effective substrate providing a large surface area and allowing fast electron transfer. The interaction between 3D rGO and surface AuPd NPs increases the activity of the sensing material. These composites were fabricated as the active layer on an indium tin oxide for DA determination. The electrode showed the best performance at a working potential of 0.25V (vs. the saturated calomel reference electrode) and a scan rate of 100mVs-1. The best electrode exhibits good sensitivity (4670μA·mM-1·cm-2), a wide linear response (0.5μM to 135μM), and a low detection limit (0.2μM). It is also selective, easily reproducible, and stable. It was applied to the determination of DA in spiked human serum and in clinical DA hydrochloride injections. The excellent performance of this electrode is attributed to the efficient electron transfer and large specific surface area of 3D rGO and to the high electrocatalytic activity of AuPd NPs due to the synergistic effect between the 3D rGO substrate and the AuPd alloy NPs. Graphical abstract An three-dimensional reduced graphene oxide (3D rGO) foam was loaded with AuPd bimetallic nanoparticles and applied to dopamine (DA) detection in human serum and an injection fluid.

Cross-linking modification with diamine monomers to enhance desalination performance of graphene oxide membranes

Two kinds of diamine molecules, including 1, 4-cyclohyxanediamine (CDA) and p-phenylenediamine (pPDA), were used as cross-linking for modification of graphene oxide (GO) nanosheets to prepare three-dimensional graphene oxide framework (GOF). Thereafter, graphene oxide composite membranes (GOCMs) were prepared on the polydopamine (PDA) modified α-Al2O3 tubes via vacuum filtration of GOF suspension. The separation performance of the GOCMs was tested for seawater desalination by pervaporation. The cross-linking modification, membrane thickness, operation temperature, feed concentration and PDA modification of α-Al2O3 tube have great effect on the separation performance of the GOCMs. Attributing to the enhancement of d-spacing and surface hydrophilicity after CDA modification, the CDA-based GOCM (CDA-GOCM) shows a higher water flux (20.1 kg m−2 h−1 with ion rejection of 99.9%) for desalination of 3.5 wt% seawater at 90 °C, which is higher than that of GO membrane (11.4 kg m−2 h−1 with ion rejection of 99.9%). However, since the hydrophilicity of the GO markedly decreases after pPDA modification, the pPDA-based GOCM (pPDA-GOCM) show a lower water flux (10.7 kg m−2 h−1 with ion rejection of 99.8%) at 90 °C. Further, the CDA-GOCM prepared on the PDA-modified α-Al2O3 tubes displays high stability for desalination of 3.5 wt% seawater.

Self-Assembly of Flexible Free-Standing Three-Dimensional Porous MoS2-Reduced Graphene Oxide Film for High-Performance Lithium-Ion Batteries

Free-standing and flexible battery electrodes are highly pursued due to its good electrochemical performance and transformation ability. Two-dimensional materials such as transition metal dichalcogenides (TMDs) and graphene with large surface area and good mechanical properties provide a good solution for this problem. The high lithium storage of MoS2 is attractive for achieving high capacity while the high conductivity of graphene is of favorable for good rate capability. The excellent mechanical properties of graphene are able to form a stable structure contributing to long cycle life, flexibility and get rid of substrates [1, 2]. A self-assembly process was developed to produce MoS2/ reduced graphene oxide (MG) hydrogel films in this work. Making use of the ordered structure existed in liquid crystalline graphene oxide (LCGO) dispersion [3], a layer structure with small MoS2 nanosheets sandwiched between large LCGO nanosheets could be easily obtained by simply mixing their dispersion together. A heating process at 70 ℃ was used to accelerate the self-assembly process. The unique layer structure turned into a three-dimensional porous structure during the self-assembly process and preserved after freeze-drying, which could effectively increase the surface area of active materials for high performance. This work develops a simple, straightforward and cost-effective method to fabricate self-assembled, layer-by-layer, free-standing porous MG hydrogel films. The structure displayed excellent electrochemical properties as a lithium-ion battery electrode [4]: a high discharge capacity of 800 mAh g-1 at a current density of 100 mA g-1; and an excellent cycling stability with slightly increased capacity (112.5%) after 500 cycles at a current density of 400 mA g-1. Such enhancement can be ascribed to the synergistic effect between these two components and gradual perfection of the ordered structure. This approach enables the exploitation of the LC order of GO sheets to organize and align 2D MoS2 in-between GO sheets, which may provide a new avenue for the development of 3D porous flexible composite electrode materials with high performance using the unique LCGO.

Tunable assembly of porous three-dimensional graphene oxide-corn zein composites with strong mechanical properties for adsorption of rare earth elements

Abstract Three-dimensional (3D) graphene oxide (GO)-based porous composites with strong compressive mechanical properties were prepared by self-assembly of corn zein (CZ) and GO through a facile hydrothermal process, which were used for the adsorption of rare earth elements (REEs) from aqueous solutions. The adsorption equilibrium for REEs by GO CZ composites could be achieved within 200 min. And the maximum adsorption capacities of GO CZ9:1 for yttrium (Y), lanthanum (La), erbium (Er), ytterbium (Yb) and neodymium (Nd) were 14.2, 17.29, 11.72, 10.08 and 9.68 mg g−1, respectively. The relatively high desorption rate (85–95%) of 3D GO CZ9:1 composite represents a higher reproducibility. Moreover, the 3D GO CZ composites obtained with a mass ratio of 3:1, 5:1 and 9:1 for GO and CZ could be compressed to 60% of their original volumes and gradually restored to their original morphologies under the corresponding stresses of 18, 16 and 11 KPa, respectively. The adsorption mechanism was also proposed.

Fabrication of a Highly Tunable Graphene Oxide Composite through Layer-by-Layer Assembly of Highly Crystalline Polyaniline Nanofibers and Green Corrosion Inhibitors: Complementary Experimental and First-Principles Quantum-Mechanics Modeling Approaches

Three-dimensional graphene oxide (GO) nanosheets were utilized as a unique versatile platform for the fabrication of an effective anticorrosion system through a layer-by-layer (L-b-L) assembly technique. In this way, the highly ordered crystalline polyaniline (Pani) nanofibers and green corrosion inhibitors (GIs) were synthesized. Sustainable corrosion inhibitors were obtained from the extract of Urtica Dioica leaves. The GO-Pani-GI nanosheets were characterized by Fourier transform infrared spectroscopy, high resolution–transmission electron microscopy, field-emission scanning electron microscopy, UV–visible spectroscopy, and thermal gravimetric analysis. In addition, the adsorption features of Pani onto GO sheets and its binding propensity against GIs were assessed by applying first-principles quantum-mechanics (QM) modeling approaches. The anticorrosion properties of the GO-Pani-GI were then examined using electrochemical impedance spectroscopy and polarization test. The results achieved from QM modeli...

Three-dimensional graphene oxide and polyvinyl alcohol composites as structured activated carbons for capacitive desalination

Membrane capacitive deionization (MCDI) is a technique that is derived from conventional capacitive deionization (CDI). Additional ion-exchange membranes are included in the MCDI cell to prevent ion-expulsion and improve cyclability. As it stands, MCDI represents the most feasible option for large scale desalination to take place. In this work, we investigate the desalination performance of a novel structured activated carbon material synthesized from the assembly of polyvinyl alcohol (PVA) on graphene oxide (GO). A hydrothermal treatment causes self-assembly of the PVA covered GO sheets and the product is a polymeric framework supported by reduced GO sheets. A further activation process by KOH produces the structured activated carbon (AC). These new structured ACs possess unique morphologies and exhibit high adsorption capacities (>30mgg−1) which far surpass traditional ACs.

Efficient hydrolysis of alkaline sodium borohydride catalyzed by cobalt nanoparticles supported on three–dimensional graphene oxide

Highly dispersed cobalt nanoparticles supported on three-dimensional graphene oxide particles (Co@3DGO) have been successfully prepared by a chemical reduction method. Cobalt presents a dispersive morphology with an average diameter of 20nm. 3DGO exhibits a stereo lamellar structure with oxygen containing functional groups which increases effective contact area and anchors the cobalt ions. Co carried on 3DGO induces a higher hydrogen generation rate (HGR) in NaBH4 hydrolysis up to 4394mLH2min−1gcobalt−1 at 298K. As well as the reaction activation energy is 37kJmol−1. Moreover, it was found that recycling performance is inverse to the concentration of NaOH. After five consecutive cycles, the recyclability retention percentage increases from 54% to 70% when the concentration of NaOH was reduced from 0.25M to 0.05M.

Facile synthesis of Ni3S2/rGO nanosheets composite on nickel foam as efficient electrocatalyst for hydrogen evolution reaction in alkaline media

Abstract

3D graphene oxide-cobalt oxide polyhedrons for highly sensitive non-enzymatic electrochemical determination of hydrogen peroxide

Polyhedrons structured cobalt oxide (Co3O4 PHs) and three-dimensional graphene oxide encapsulated cobalt oxide polyhedrons (3D GO-Co3O4 PHs) were synthesized via facile hydrothermal synthetical route for the highly sensitive determination of hydrogen peroxide (H2O2). The morphological study clearly revealed the polyhedron shaped Co3O4 and additionally elemental, diffraction, and electrochemical studies were performed to verify the structure and shape. Owing to excellent synergy between Co3O4 PHs and GO, the composite possesses good porosity, large electrochemical area, roughened surface, and excellent electrocatalytic ability. The development of highly sensitive sensor is essential for H2O2 due to its great significance in physiological, biochemical, pharmaceutical and medicinal applications. A rapid, sensitive, selective, reproducible, and durable non-enzymatic H2O2 assay, by employing 3D GO-Co3O4 PHs modified electrode was described. The sensor offered excellent sensitivity with detection limit of 15nM, which is superior to those of previously reported sensors. A real-time analysis was demonstrated in commercially acquired contact lens and disinfectant cleaning solutions without pre-treatment.

Monolayer polymerization of polyhedral oligomeric silsesquioxane on graphene oxide for highly efficient adsorption of β-lactoglobulin

We report the self-assembly of monolayer polyhedral oligomeric silsesquioxane (POSS) on graphene oxide (GO), where GO acts as a directing template along with the assembly of POSS into a three-dimensional porous framework structure, shortly termed as PPG. The PPG framework contains ultrathin nanopetals with a thickness of ca. 1.95 nm, giving rise to reduced restacking and high surface area. The PPG framework exhibits a high adsorption capacity of up to 1570.3 mg g−1 towards β-lactoglobulin, in addition to a favorable selectivity against other protein species with similar isoelectric points to that of β-lactoglobulin. This might be attributed to the specific hydrogen-bonding donor-acceptor interaction between the calyx structure of β-lactoglobulin and the PPG framework. Satisfactory separation performance of PPG is confirmed by the selective discrimination and isolation of β-lactoglobulin from complex biological sample matrixes, e.g., milk whey. This observation provides a promising approach for the construction of monolayer polymer-modified three-dimensional graphene oxide composites with specific biological application potentials.

Self-assembled 3D mesoporous graphene oxides (MEGOs) as adsorbents and recyclable solids for CO2 and CH4 capture

Various graphene derivatives have been extensively synthesized and used in several research areas. Currently, however, very few examples of graphene derivatives that exhibit mesoporosity have been reported. In this work, we describe a facile method based on a self-assembly process of two-dimensional (2D) graphene oxides in aqueous solutions to produce three-dimensional (3D) mesoporous graphene oxide (MEGO) solids. The resulting MEGO solids exhibit exceptionally narrow mesopore distributions (2.4nm), high surface areas, large pore volumes and high thermal stabilities (>450°C). The MEGOs were used as adsorbents for CO2 and CH4; they showed good adsorption performance, particularly for CO2 at high pressures and remarkable recyclability, suggesting this material is a potential candidate to be used as adsorbent in precombustion process.

The effect of titanium nickel nitride decorated carbon nanotubes-reduced graphene oxide hybrid support for methanol oxidation

Titanium nickel nitride (TiNiN) decorated three-dimensional (3D) carbon nanotubes-reduced graphene oxide (CNT-rGO), a fancy 3D platinum (Pt)-based catalyst hybrid support, is prepared by a solvothermal process followed by a nitriding process, which is tested as anodic catalyst support for the methanol oxidation reaction (MOR). The structure, morphology and composition of the synthesized TiNiN/CNT-rGO exhibits a uniform particle dispersion with high purity and interpenetrating 3D network structure. Notably, Pt/TiNiN/CNT-rGO catalyst exhibits significantly improved catalytic activity and durability for methanol oxidation in comparison with Pt/CNT-rGO and conventional Pt/C (JM). The outstanding electrochemical performance was attributed to structure and properties. That is, the 3D CNT-rGO provided a fast transport network for charge-transfer and mass-transfer as well as TiNiN NPs with good synergistic effect and the strong electronic coupling between different domains in TiNiN/CNT-rGO, thus the catalytic activity of the novel catalyst is greatly improved. These results evidences 3D TiNiN/CNT-rGO as a promising catalyst support for a wide range of applications in fuel cells.

High-Performance Three-Dimensional Mesoporous Graphene Electrode for Supercapacitors using Lyophilization and Plasma Reduction.

In this study, a three-dimensional (3D) mesoporous plasma-reduced graphene oxide web (mPrGO web) was fabricated via lyophilization of graphene oxide (GO) solution and subsequent plasma reduction. The lyophilized graphene oxide web (GO web) was successfully reduced by a short plasma treatment (<2 s) using a commercially available plasma apparatus. The degree of reduction of the mPrGO web was determined by the applied plasma power (W) of the apparatus; the optimum power level for effective reduction was identified. The as-synthesized mPrGO web showed a high degree of reduction and robust graphitic characteristics, with a unique crack-like mesoporous structure created on corrugated graphene sheets. In addition to the above characteristics, the mPrGO web possessed a 3D web-like architecture that provided enhanced surface area along with ion-transportable channels derived from lyophilization. Owing to the synergistic effect of lyophilization and plasma reduction, the mPrGO web exhibited high electrical conductivity (87 S cm-1) and increased surface area (642 m2 g-1). Accordingly, the mPrGO web showed outstanding specific capacitance of 253.8 F g-1 at 0.2 A g-1 along with the excellent rate capability (76% capacitance retention at 5 A g-1). Furthermore, the assembled all-solid-state symmetric supercapacitor also exhibited remarkable electrochemical performances, demonstrating the potential applicability of the mPrGO web as an effective supercapacitor electrode material.