Graphene Oxide Aerogel Research Articles

Vacancy-Rich MoSSe with Sulfiphilicity-Lithiophilicity Dual Function for Kinetics-Enhanced and Dendrite-Free Li-S Batteries.

The sluggish redox kinetics of sulfur and the uncontrollable growth of lithium dendrites are two main challenges that impede the practical applications of lithium-sulfur (Li-S) batteries. In this study, a multifunctional host with vacancy-rich MoSSe vertically grown on reduced graphene oxide aerogels (MoSSe/rGO) is designed as the host material for both sulfur and lithium. The embedding of Se into a MoS2 lattice is introduced to improve the inherent conductivity and generate abundant anion vacancies to endow the 3D conductive graphene based aerogels with specific sulfiphilicity-lithiophilicity. As a result, the assembled Li-S batteries based on MoSSe/rGO exhibit greatly improved capacity and cycling stability and can be operated under a lean electrolyte (4.8 μL mg-1) and a high sulfur loading (6.5 mg cm-2), achieving a high energy density. This study presents a unique method to unlock the catalysis capability and improve the inherent lithiophilicity by heteroatom doping and defect chemistry for kinetics-enhanced and dendrite-free Li-S batteries.

Ultralight, tunable monolithic SiC aerogel for electromagnetic absorption with broad absorption band

SiC aerogel is a novel candidate for electromagnetic absorption (EMA) materials in extreme environments because of its ceramic nature and aerogel morphology. In this study, graphene oxide (GO), which having has been generally serving served as a “brick” in the material community, was used as a building block to prepare SiC aerogel precursors and further develop a novel and designable route for preparing SiC aerogel for EMA. The experimental results suggested that the GO aerogel was well converted into a SiC aerogel with ultra-low density (<4 mg cm−3). The synthesized SiC aerogel inherited the precursor well in structure while having a wide absorption band (approximately 5.5GHz) and a high absorption frequency-to-thickness correlation different from traditional SiC aerogels. The above idea for designing and assembling SiC aerogels will significantly broaden the practical applications of GO and SiC in EMA, supercapacitors and sensors.

Montmorillonite-reduced graphene oxide composite aerogel (M−rGO): A green adsorbent for the dynamic removal of cadmium and methylene blue from wastewater

In this study, a type of montmorillonite-reduced graphene oxide aerogel (M−rGO) was successfully prepared by the sol–gel method and used for the effective removal of heavy metals (cadmium, Cd) and cationic dyes (methylene blue, MB) in wastewater. The chemical composition and micromorphology of the resulting M−rGO were characterized utilizing scanning electron microscopy and energy dispersive spectrometry, Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy, and X-ray diffraction. Furthermore, the effects of the initial concentration, adsorption time, and temperature on the static adsorption process were systematically studied. Equally important, the effects of the concentration, pH, ionic strength (IS), and pumping flow rate of contaminated solution on the dynamic removal of Cd and MB by M−rGO were investigated by a fixed-bed column experiment. The kinetics, isothermals, and thermodynamic adsorption experiment results showed that the Langmuir and pseudosecond-order models best suited the adsorption process in which physical adsorption and chemical adsorption act together. Functional groups containing O and C were involved in the adsorption of Cd and MB, and the hydrogen bonds, π-π, n-π interaction, and hydrophobic interaction between M−rGO and MB made important contributions to adsorption. The lower initial concentration, higher pH value, and slower pumping flow rate of the contaminated solution can effectively increase the dynamic adsorption capacity of Cd and MB on M−rGO. Contrary to that of Cd, the adsorption capacity of MB on M−rGO increased with IS. Both static adsorption and dynamic column experiments confirmed that the presence of Cd promoted the adsorption of MB, and MB inhibited the adsorption of Cd by M−rGO. In addition, the Cd/MB combined pollution wastewater experiment and the regeneration study showed that M−rGO could be a cost-effective and promising sorbent for Cd and MB wastewater treatment due to its high efficiency and excellent reusability.

Carbon hybrid aerogel-based phase change material with reinforced energy storage and electro-thermal conversion performance for battery thermal management

Driven by the growing of electric vehicle, there is an unmet need to develop wide-range temperate management of Li-ion battery. Promising phase change materials (PCMs) with reinforced energy storage and conversion performance can cool battery by heat storage and heat battery by electro-thermal conversion. Herein, carbon hybrid aerogel by integrating MOF-derived carbon (MOFC) and graphene oxide (GO) aerogel was fabricated to encapsulate lauric acid as LA@MOF-C/GO PCM composite. Densely network of the hybrid aerogel works to enhance electrical/thermal conductivities while synergistic effect between MOF-C and GO helps to improve PCM loading capacity. Consequently, the PCM composite exhibited enhanced heat storage and electro-thermal conversion performances including low input voltage (2.2 V), high electro-thermal efficiency (90%), and enhanced enthalpy (140 J/g), thermal conductivity (1.35 W/mK) and shape-stability (10 °C above m.p.). The LA@MOF-C/GO composite worked efficiently to improve battery performance under environment temperature ranging from 45 °C to −20 °C, which shows great potential in thermal management of electric vehicle battery.

Controlling surface porosity of graphene-based printed aerogels

The surface porosity of graphene-based aerogels strongly influences their performance in applications involving mass transfer. However, the factors determining the surface porosities are not well-understood, hindering their application-specific optimisation. Here, through experiments and hydrodynamic simulations, we show that the high shear stress during the graphene-based aerogel fabrication process via 3D printing leads to a non-porous surface. Conversely, crosslinking of the sheets hinders flake alignment caused by shearing, resulting in a porous surface. Our findings enable fine control of surface porosity of printed graphene-oxide aerogels (GOA) through regulation of the crosslinking agents and shear stress. Using this strategy, we demonstrate the performance advantages of GOA with porous surface over their non-porous counterpart in dye adsorption, underscoring the importance of surface porosity in certain application scenarios.

Integration of 3D macroscopic reduced graphene oxide aerogel with DUT-67 for selective CO2 photoreduction to CO in Gas-Solid reaction

Herein, DUT-67/RGO aerogel photocatalysts with three-dimensional (3D) macroscopic morphology were first prepared by a facile hydrothermal and freeze-drying process. It was observed that DUT-67 endowed aerogels with strong adsorption/activation capacity for CO2 molecules. Besides, RGO not only dispersed DUT-67 as a macroscopic carrier, but also improved the utilization rate of light energy. The high conductivity of RGO and the strong interaction with DUT-67 enhanced the electron coupling effect, which was conducive to the separation of carriers. 15D/R achieved near 99.6% selectivity at the gas–solid interface for UV–Vis light-driven CO2 reduction to CO, with a rate of 42.41 μmol·g−1. The adsorption behavior of products at the interface and formation process of intermediates were monitored based on CO-TPD and in situ Fourier transform infrared spectra. The extremely high selectivity for CO came from the weak adsorption of CO on the surface of 15D/R and formation of CH4 required more complex intermediates.

Metal–Organic Frameworks Derived Electrolytes Build Multiple Wetting Interfaces for Integrated Solid‐State Lithium–Oxygen Battery

AbstractSolid‐state lithium–oxygen (Li–O2) batteries are considered as the next‐generation solution for high‐safety energy storage systems to overcome the persistent problems associated with liquid battery systems. However, the absence of stable solid‐state electrolytes (SSEs) and the design complexity of functional solid‐state cathode (SSC) remains a fundamental challenge. Here, a high‐performance solid‐state Li–O2 battery is presented with Li‐ion‐conducted UiO‐67 (UiO‐67‐Li) as SSEs and UiO‐67‐Li@reduced graphene oxide (rGO) aerogel integrated structure as SSC. The UiO‐67‐Li SSEs reveal exceptional conductivity (0.64 mS cm−1 at 25 °C) along with high chemical/electrochemical robustness. Furthermore, the prepared UiO‐67‐Li@rGO aerogel exhibits continuous and abundant Li+/e− transfer and O2 diffusion channels. Benefiting from the unique chemical properties of the UiO‐67‐Li SSEs layer, the solid‐state Li–O2 battery achieves suppression of anode dendrite formation, resistance to air‐corrosion, and presence of multiple low‐impedance wetting interfaces including anode/electrolyte and electrolyte/cathode. This ingenious arrangement endows the solid‐state Li–O2 battery with low overpotential (0.8 V), superior rate capability, and stable cycling life (up to 115 cycles). This novel design and exciting result will open up one avenue for the development of MOF‐based SSEs and cathodes for high‐performance solid‐state Li–O2 batteries and other solid‐state energy‐storage devices.

MoS2 Decorated Silver Nanowire-Reduced Graphene Oxide Aerogel Micro-Particle for Thermally Conductive Polymer Composites with Enhanced Flame Retardancy.

Multifunctional polymer composites with efficient heat dissipation and flame retardancy are highly desirable in the electronic industry. Here, by the combination of hydrothermal reaction and in situ fragmentation, molybdenum disulfide (MoS2 ) decorated silver nanowires (AgNWs) and 3D reduced graphene oxide (RGO) (AgNW-RGO@MoS2 ) aerogel micro-particles (AMPs) are successfully prepared. When the above AMP is introduced to epoxy (EP) resin by the simple blending method, a polymer composite with continuous thermally conductive pathways and flame barrier layers is achieved. With an AMP loading of 4.0vol.%, the polymer composite displays superior enhancement in thermal conductivity up to 420%. Compared to neat EP, the peak heat release rate and total heat release decreases by 61.1% and 58.8%, respectively. This work provides new insights into the design and large-scale fabrication of multifunctional polymer composites for efficient thermal management materials.

Ionic liquid modified graphene aerogel as efficient electrode material for supercapacitors based on ionic liquid electrolyte

The simultaneous enhancement of energy density (E) and power density (P) is a highly pursued but difficult task in domain of supercapacitors, which necessitates good electrode/electrolyte compatibility, high electron/ion migration rates, and wide voltage window. Herein, an ionic liquid (IL) assisted hydrothermal reduction and modification tactics is employed to prepare 1-benzyl-3-methyl imidazolium cysteine ([Bzmim][Cys]) IL-modified reduced graphene oxide aerogel material (IL-rGA). The porous texture with suitable pore sizes and IL-modified surface of IL-rGA ensures rapid infiltration and sufficient adsorption of electrolyte ions, and therefore substantially enhances the specific capacitance. The symmetric IL-rGA supercapacitor using 1-ethyl-3-methyl tetrafluoroborate IL electrolyte delivers high E values of 104–33 W h kg−1 in the P range of 944–15,860 W kg−1, these output parameters can meet the requirements in more widespread electric facilities. The current work offers a promising way to enhance and balance the E and P values of carbonaceous supercapacitors via the surface modification of electrode materials and the matching with IL electrolytes.

Construct α-FeOOH-Reduced Graphene Oxide Aerogel as a Carrier for Glucose Oxidase Electrode.

A promising α-FeOOH-reduced graphene oxide aerogel (FeOOH-GA) has been prepared for the assembly of an enzyme electrode. The α-FeOOH-reduced graphene oxide aerogel was characterized by X-ray powder diffraction, field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, Raman, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The results reveal that graphene oxide is reduced by Fe2+ ion and α-FeOOH nanorods anchored on the reduced graphene oxide sheet through the Fe-O-C bond. Analyses using scanning electron microscopy and the Brunauer–Emmett–Teller method show that FeOOH-GA displays a various and interconnected pore structure. The FeOOH-GA was used as a support material on the glass carbon electrode (GCE) for glucose oxidase (GOD). Electrochemistry properties and bioelectrocatalytic activities of Nafion/GOD/FeOOH-GA/GCE were achieved from cyclic voltammetry and electrochemical impedance spectroscopy. The results show that Nafion/GOD/FeOOH-GA/GCE maintains outstanding catalytic activity and electrochemical properties. The FeOOH-GA could immobilize GOD through the hydrophobicity of the reduced graphene oxide and hydroxide radical of α-FeOOH. Appropriate α-FeOOH and diversified pore structure are beneficial for electron transfer, enzyme electrode storage, and interfacial electron transfer rate. All results indicated that the α-FeOOH-reduced graphene oxide aerogel as a carrier could effectively immobilize the tested enzyme.

Ultralight Magnetic and Dielectric Aerogels Achieved by Metal–Organic Framework Initiated Gelation of Graphene Oxide for Enhanced Microwave Absorption

HighlightsMetal–organic frameworks (MOFs) are used to directly initiate the gelation of graphene oxide (GO), producing MOF/rGO aerogels.The ultralight magnetic and dielectric aerogels show remarkable microwave absorption performance with ultralow filling contents.The development of a convenient methodology for synthesizing the hierarchically porous aerogels comprising metal–organic frameworks (MOFs) and graphene oxide (GO) building blocks that exhibit an ultralow density and uniformly distributed MOFs on GO sheets is important for various applications. Herein, we report a facile route for synthesizing MOF/reduced GO (rGO) aerogels based on the gelation of GO, which is directly initiated using MOF crystals. Free metal ions exposed on the surface of MIL-88A nanorods act as linkers that bind GO nanosheets to a three-dimensional porous network via metal–oxygen covalent or electrostatic interactions. The MOF/rGO-derived magnetic and dielectric aerogels Fe3O4@C/rGO and Ni-doped Fe3O4@C/rGO show notable microwave absorption (MA) performance, simultaneously achieving strong absorption and broad bandwidth at low thickness of 2.5 (− 58.1 dB and 6.48 GHz) and 2.8 mm (− 46.2 dB and 7.92 GHz) with ultralow filling contents of 0.7 and 0.6 wt%, respectively. The microwave attenuation ability of the prepared aerogels is further confirmed via a radar cross-sectional simulation, which is attributed to the synergistic effects of their hierarchically porous structures and heterointerface engineering. This work provides an effective pathway for fabricating hierarchically porous MOF/rGO hybrid aerogels and offers magnetic and dielectric aerogels for ultralight MA.

Honeycomb-like rGO aerogels via oriented freeze-drying as efficient organic solvents removing absorbents

It is essential to synthesize materials that fit versatile application backgrounds in our life through structural design method. As we all know, channel design is one of the crucial factors in catalysts and absorbent materials synthesis. In this study, we have fabricated honeycomb-like structured and porous rGO (reduced graphene oxide) aerogels by oriented structural design. The synthesis process endowed the rGO aerogels with the regular capillary channels. And it was demonstrated to possess a high absorption capacity for organic solvent ranging from 251 to 396 times (chloroform) of its own mass. Moreover, owing to its high mechanical compression, it can be recycled many times by squeezing out the organic solvent from the channels. Due to its unique performance in absorption and mechanical compression, the rGO aerogel is an ideal absorbent for polluted water treatment applications.

Reduced graphene oxide based aerogels: Doped with ternary Prussian blue analogs and selective removal of Cs+ from effluent

Reduced graphene oxide aerogels doped with ternary Prussian blue analogs (RGOA/TPBAs) were developed by controlled self-assembly tactics and applied to remove radioactive cesium (Cs) from effluent. The unique three-dimensional layered structure gives RGOA/TPBAs excellent mechanical strength and high-level specific surface area, which facilitates the exposure of adsorption points and thus promotes the adsorption of Cs+. A maximum adsorption capacity of 226.98 mg g−1 (dosage = 0.25 g L−1, pH = 7, T = 298.15 K) was obtained for the composite material, which exhibited excellent adsorption performance for cesium. In addition, RGOA/TPBAs maintained an excellent Cs+ selectivity in a solution containing other ions (m V−1 = 0.25 g L−1, Mn+ = Ca2+, Mg2+, Na+, K+, [Cs+]initial = 10 mg L−1) and the removal rate is more than 90%. The proposed secondary kinetic model (R2 = 0.9982) and fitted the adsorption process well, as does the Langmuir isotherm model (R2 = 0.9929), making it clear that the adsorption is homogeneous monolayer chemisorption. The coexisting ion adsorption experiments illustrate that the good selectivity of the composite.

Multifunctional electromagnetic interference shielding 3D reduced graphene oxide/vertical edge-rich graphene/epoxy nanocomposites with remarkable thermal management performance

Owing to the growing electromagnetic interference (EMI) shielding and heat removal issues in modern electronics, polymer composites with remarkable EMI shielding performance and thermal management capability have attached much attention. In this work, vertical edge-rich graphene (ERG) were in-situ grown on the reduced graphene oxide (rGO) aerogel skeleton, constructing a unique 3D hybridized carbon nanostructures with covalent bonding, which were applied to modify epoxy resin for EMI shielding and thermal management. Impressively, the obtained rGO-ERG/epoxy nanocomposites possessed an improved EMI shielding performance of 45.9 dB in the X-band, which mainly attributes to the structural defects and strong charge polarization ability of ERG. Furthermore, theoretical models qualitatively prove that the construction of phonon-matching 3D rGO-ERG networks results in efficient phonon transport, providing an enhanced thermal conductivity of 1.96 W m−1 K−1. Meanwhile, the 3D hybrid structure from total 2D ingredients which exhibits a remarkable thermal management capability is further corroborated. More importantly, this strategy endows rGO-ERG/epoxy nanocomposites comprehensive functions, providing a bright application prospect for next-generation electronic packing.

A hierarchically combined reduced graphene oxide/Nickel oxide hybrid supercapacitor device demonstrating compliable flexibility and high energy density

This work demonstrates a hierarchical structure design with mixed holey graphene oxide (HGO) and Ni(OH)2 active material layer made by one-pot hydrothermal reaction clinging to Nickel foam as backbone and ice-template oriented graphene oxide (GO) aerogel as filling, aiming to create an asymmetric solid supercapacitor (ASC) device with compliable flexibility and high electrochemical performance. The effects of hydrothermal treatment and ice-template freezing parameters on electrochemical stability under repeated exterior deformation are discussed, the optimal parameters result in a high areal capacitance of 479.8 mF/cm2 in asymmetric supercapacitor device setup. The use of porous HGO and oriented GO aerogel synergistically contribute to the high energy and power density up to 1.69 Wh/m2 and 9 W/m2 as well as excellent electrochemical performance retention under repeated curving deformation which reaches 102% thanks to a novel activation process. The electrode assembly including metal foam and the buffering GO aerogel should be instructive for future supercapacitor design.

Arginine containing chitosan-graphene oxide aerogels for highly efficient carbon capture and fixation

Carbon dioxide (CO2) gas is the main greenhouse gas and is primarily responsible for global warming and climate change. The greatest challenge in contemporary environmental research is reducing anthropogenic CO2 gas in the atmosphere by developing effective and efficient materials and control methods. We propose chitosan–graphene oxide and arginine-based aerogels for CO2 capture and fixation characterized using Fourier transform infrared spectroscopy, X-ray diffraction analysis, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, Brunauer–Emmett–Teller analysis, and thermogravimetric analysis (TGA). The chitosan-based aerogel was used as a CO2 adsorbent and its CO2 gas adsorption capacity was measured using the TGA method on its solid surface. The CO2 gas adsorption was equal to 24.15 wt% (5.48 mmolg-1) at 35 °C for 35 min. Chitosan–graphene oxide and arginine-based aerogels exhibited a much higher CO2 capture capacity than that of pure chitosan. Chitosan–graphene oxide and arginine-based aerogels were used as catalysts for the insertion of CO2 into organic molecules leading to the formation of new organic molecules with the help of a cocatalyst. The fixation of CO2 with epoxide was observed using gas chromatography-mass spectrometry. Thus, our findings can aid in reducing anthropogenic CO2 gas from the atmosphere by synthesizing new organic compounds using anthropogenic CO2.

Superhydrophilic Modified Elastomeric RGO Aerogel Based Hydrated Salt Phase Change Materials for Effective Solar Thermal Conversion and Storage

As a typical phase-change material (PCM) with high heat storage capacity and wide distribution, hydrated salts play broad and critical roles in solar energy utilization in recent years. However, the leakage and supercooling problems of hydrated salts have been a constraint to their further practical applications. In the current work, the super-hydrophilic reduced graphene oxide (RGO) aerogels modified by konjac glucomannan (KGM) as supporting structural materials are prepared by the hydrothermal reaction-freeze-drying, which can effectively absorb and convert visible sunlight energy into thermal energy. In addition, the super-hydrophilic aerogels compounded with PCMs can ameliorate the shortcoming of leakage and suppress the supercooling temperature as low about 0.2-1.5 °C in the freezing process. Under 1 sun irradiation, the prepared sodium acetate trihydrate/KGM-modified graphene oxide aerogel (SAT/KRGO) composite PCM achieves a high photothermal conversion efficiency (86.3%) due to its good light absorption property. The number of cycles has no apparent effect on the supercooling of the composite materials, suggesting their stable thermal cycles and thermal storage.

The Effect of the 3D Nanoarchitecture and Ni‐Promotion on the Hydrogen Evolution Reaction in MoS2/Reduced GO Aerogel Hybrid Microspheres Produced by a Simple One‐Pot Electrospraying Procedure

The transition toward renewable energy sources requires low-cost, efficient, and durable electrocatalysts for green H2 production. Herein, an easy and highly scalable method to prepare MoS2 nanoparticles embedded in 3D partially reduced (pr) graphene oxide (GO) aerogel microspheres (MoS2 /prGOAMs) with controlled morphology and composition is described. Given their peculiar center-diverging mesoporous structure, which allows easy access to the active sites and optimal mass transport, and their efficient electron transfer facilitated by the intimate contact between the MoS2 and the 3D connected highly conductive pr-GO sheets, these materials exhibit a remarkable electrocatalytic activity in the hydrogen evolution reaction (HER). Ni atoms, either as single Ni atoms or NiO aggregates are then introduced in the MoS2 /prGOAMs hybrids, to facilitate water dissociation, which is the slowest step in alkaline HER, producing a bifunctional catalyst. After optimization, Ni-promoted MoS2 /prGOAMs obtained at 500°C reach a remarkable η10 (overpotential at 10mA cm-2 ) of 160mV in 1 m KOH and 174mV in 0.5 m H2 SO4 . Moreover, after chronopotentiometry tests (15 h) at a current density of 10mA cm-2 , the η10 value improves to 147mV in alkaline conditions, indicating an exceptional stability.

Multilayer structured CNF/rGO aerogels and rGO film composites for efficient electromagnetic interference shielding

The development of efficient electromagnetic interference (EMI) shielding materials with high electromagnetic waves (EMWs) absorption capacity is of great significance to alleviate secondary EMWs pollution. Herein, multilayered composites were prepared by stacking cellulose nanofibril (CNF)/reduced graphene oxide (rGO) aerogels and rGO film together. The porous aerogels and the dense film serve as the EMWs absorbing layer and reflecting layer, respectively. When the EMWs enter the multilayer composites, they go through the process of absorption-reflection-reabsorption, resulting in a high EMI shielding effectiveness (SE) of ~32 dB. Furthermore, both experimental and theoretical analyses were adopted to explore the effect of arrangement order of CNF/rGO aerogels on EMI shielding performance. The results indicate that composites with progressively higher graphene content exhibit a higher EMWs absorption capacity at the same total EMI SE. This work offers a feasible design for improving EMWs absorption without affecting the overall EMI shielding performance of the material.

Graphene Oxide Aerogel Foam Constructed All-Solid Electrolyte Membranes for Lithium Batteries.

With the development of electric vehicles and products, lithium metal batteries with solid-state electrolytes have shown a broad application prospect. However, the uneven deposition of lithium, low ion conductivity, narrow electrochemical window, and high interfacial impedance limit the safety and performance of the solid-state batteries. Herein, we develop a non-ceramic solid electrolyte based on the graphene oxide aerogel frame filling with polyethylene oxide (GSPE). The resulting uniform and resilient framework structure form a continuous Li-ion adsorption zone, which ensures uniform ion-current distribution at the interface while obtaining the relatively high ionic conductivity, effectively preventing the uneven deposition of lithium, and thus greatly improving the battery stability. Comprehensive electrochemical analysis showed that GSPE achieved an ionic conductivity of 4.12 × 10-4 S cm-1 at 50 °C. The assembled LiFePO4(LFP) |GSPE| Li full battery can stably cycle for more than 100 cycles at 0.1 C, and the lithium symmetrical battery can continuously be plating-peeling for more than 600 h at 0.1 mA cm-2. The method of using the carbon aerogel structure to achieve the uniform deposition of lithium ions has explored a new possible research direction for all-solid-state batteries.