Reduced Graphene Oxide Hybrid Research Articles

Facile synthesis of Co0.5Zn0.5Fe2O4 nanoparticles decorated reduced graphene oxide hybrid nanocomposites with enhanced electromagnetic wave absorption properties

Herein, reduced graphene oxide/cobalt-zinc ferrite (RGO/Co0.5Zn0.5Fe2O4) hybrid nanocomposites were fabricated by a facile hydrothermal strategy. Results revealed that the contents of RGO could affect the micromorphology, electromagnetic parameters and electromagnetic wave absorption properties. As the contents of RGO increased in the as-synthesized hybrid nanocomposites, the dispersibility of the particles was improved. Meanwhile, numerously ferromagnetic Co0.5Zn0.5Fe2O4 particles were evenly anchored on the wrinkled surfaces of flaky RGO. Besides, the obtained hybrid nanocomposites exhibited superior electromagnetic absorption in both X and Ku bands, which was achieved by adjusting the RGO contents and matching thicknesses. Significantly, when the content of RGO was 7.4 wt%, the binary nanocomposites showed the optimal reflection loss of -73.9 dB at a thickness of 2.2 mm and broadest effective absorption bandwidth of 6.0 GHz (12.0–18.0 GHz) at a thin thickness of merely 2.0 mm. The enhanced electromagnetic absorption performance was primarily attributed to the multiple polarization effects, improved conduction loss caused by electron migration, and magnetic loss derived from ferromagnetic Co0.5Zn0.5Fe2O4 nanoparticles. Our results could provide inspiration for manufacturing graphene-based hybrid nanocomposites as high-efficient electromagnetic wave absorbers.

Hybrid Reduced Graphene Oxide with Special Magnetoresistance for Wireless Magnetic Field Sensor

HighlightsCost-effective and time-efficient process for hybrid reduced graphene oxide (rGO) nanosheets with special magnetoresistance properties was fabricated.The prepared hybrid rGO nanosheets have large magnetoresistance at low magnetic field at room temperature and used in wireless magnetic field sensors for quick detection of low electromagnetic radiation.

3D reduced graphene oxide hybrid nano-copper scaffolds with a high antibacterial performance

Three-dimensional (3D) graphene/nano-copper scaffolds (rGCSs) was fabricated using a one-step chemical deposition on 3D reduced graphene oxide architecture (rGOA). The nano-copper was conformably grown on the rGOA substrate with a uniform morphology. Due to combined effects between the graphene skeleton and the nano-copper, the rGCSs demonstrated excellent antibacterial properties in the colony counting experiments. In addition, an rGCSs device was designed to further investigate the antibacterial performance for sewage management. The antibacterial killing rate was up to 100% for Escherichia coli and Staphylococcus aureus, and the nano-copper deposits were immobilized on the reduced graphene oxide sheets during the circulation process. This suggests that rGCSs is a highly-efficient antibacterial candidate for practical applications in sewage systems.

Branched Alkylamine-Reduced Graphene Oxide Hybrids as a Dual Proton-Electron Conductor and Organic-Only Water-Splitting Photocatalyst.

We report multifunctionalities including the solid electrolytic property, electron conductivity (EnC), and photocatalytic water splitting (PWS) ability of organic-only hybrids obtained by intercalating short and branched-chain alkylamines including methylamine (MA), butylamine (BA), pentylamine (PA), and isomethylbytylamine (IMBA) in reduced graphene oxide (rGO). The alkylamine-rGO hybrids were synthesized by a facile solid-state reduction process. Within the series, IMBA-rGO exhibited high proton conductivity (PrC), EnC, and optimized PWS capacity. The PrC of IMBA-rGO was from 10-4 to 10-3 S cm-1, which is only half an order less than that for pristine GO. The EnC was 1.25 μA/V. Though the PWS performances of MA-rGO, BA-rGO, and PA-rGO were comparatively lower, IMBA-rGO could generate about 1.5 times H2 compared with that for R-TiO2. The IR spectra indicate the association of IMBA and GO by chemical bonds. The Raman spectra show the transformation of GO's nonconductive sp3 carbon sites into electron-conductive sp2 carbon centers. The thermogravimetric analysis show improved water adsorbing capacity of IMBA-rGO, which resulted in higher PrC. Doping of the nitrogen atom at the graphitic sp2 system was confirmed from the presence of pyrrolic N in X-ray photoelectron spectroscopy spectra. The resultant N-type semiconducting behavior is majorly responsible for the PWS process. The powder X-ray diffraction analysis indicates a more flexible interlayer space in IMBA-rGO, which facilitates both the reformation of hydrogen bonds during proton conduction and water dynamics during photocatalysis. The material indicates the possibility of devising graphene-based organic-only multifunctional hybrids.

Ultrasensitive Non-Enzymatic Glucose Sensors Based on Hybrid Reduced Graphene Oxide and Carbonized Silk Fabric Electrodes Decorated with Cu Nanoflowers

The preparation of substrate with high specific surface area and conductivity is very important in the development of non-enzymatic glucose sensors. This study presents a non-enzymatic glucose sensor electrode based on a hybrid reduced graphene oxide (rGO) and carbonized silk fabric (CSF) substrate obtained by immersing silk fabric in a graphene oxide solution and carbonizing at 950 °C in an Ar atmosphere, and then decorating the rGO/CSF surface with Cu nanoflowers by electrodeposition. The optimum Cu-rGO/CSF sensor electrode exhibits high glucose sensitivities of 6613.3 μA mM−1 cm−2 and 1541.7 μA mM−1 cm−2 with linear responses over separate glucose concentration ranges of 0.05–4.0 mM and 4.0–7.0 mM due to the rGO/CSF substrate has high specific surface area, good conductivity and the Cu nanoflowers have high catalytic activity. The electrode also provides a lower limit of detection of 2.27 μM at a signal-to-noise ratio of 3 and high stability in the air. These results demonstrate that the proposed electrode material facilitates the development of simple and accurate non-enzymatic glucose sensors.

Hollow cobalt oxide nanoparticles embedded porous reduced graphene oxide anode for high performance lithium ion batteries

Hollow cobalt oxide nanoparticles embedded porous reduced graphene oxide hybrids are constructed by means of a facile etching strategy and the Kirkendall effect. When examined as an anode for lithium-ion batteries, this unique structured composite exhibits remarkable lithium storage capability such as excellent rate capability, superior reversible specific capacity together with good cycling durability, highlighting the importance of embedding active materials on graphene sheets for maximum utilization of hollow structured cobalt oxide and porous reduced graphene oxide for energy devices.

An ultrasmall Ru2P nanoparticles–reduced graphene oxide hybrid: an efficient electrocatalyst for NH3 synthesis under ambient conditions

A Ru2P–reduced graphene oxide hybrid acts as a superior catalyst for electrochemical N2 fixation in 0.1 M HCl, achieving a large NH3 yield of 32.8 μg h−1mgcat.−1 and a high faradaic efficiency of 13.04%−0.05 V vs. the reversible hydrogen electrode.

An Ag–TiO2–reduced graphene oxide hybrid film for electrochemical detection of 8-hydroxy-2′-deoxyguanosine as an oxidative DNA damage biomarker

Here, a notably sensitive and selective electrochemical sensor based on an Ag–TiO2–rGO hybrid nanomaterial modified SPE was developed for 8-OHdG detection, which is a significant DNA biomarker due to one of the main products of oxidative DNA damage.

The construction of CuCo2O4/N-doped reduced graphene oxide hybrid hollow spheres as anodes for sodium-ion batteries

Hierarchical CuCo2O4/N-doped reduced graphene oxide (CuCo2O4/N-rGO) hollow hybrid nanospheres was constructed and further applied as highly capacity anode materials for SIBs.

Removal mechanism of mitoxantrone by a green synthesized hybrid reduced graphene oxide @ iron nanoparticles.

Anti-tumor drugs, due to their non-specific toxicity will cause long-term delayed toxicity to organisms and humans when discharged into the environment. In this study, reduced graphene oxide @ iron nanoparticles (rGO@Fe NPs) were successfully prepared using green tea extract as reductant and subsequently used for mitoxantrone (MTX) removal. SEM and Raman spectroscopy showed that 30-60nm sized Fe NPs were loaded on rGO and green tea extract successfully reduced GO to rGO. The removal efficiency of MTX by the hybrid material was higher (98.5%) than either rGO (77.5%) or Fe NPs (53.1%) alone. In addition, the removal efficiency of MTX by the hybrid material was as high as 95% within 5min, MTX adsorption followed both a pseudo-second-order kinetic model and the Langmuir isotherm, and it is a spontaneous adsorption. Recycling experiments showed that the removal efficiency of MTX decreased from 99.9 to 76.8% after six cycles, and could be as high as 99% in both municipal and medical wastewater. Scanning electron microscopy (SEM), Fourier transform infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and High performance liquid chromatography (HPLC) were all used to characterize and analyze the hybrid material, and possible adsorption mechanisms which revealed that MTX adsorption probably involved a combination of π-π stacking interaction, hydrogen bonding, electrostatic interaction and pore-filling.

Pd/MXene(Ti3C2Tx)/reduced graphene oxide hybrid catalyst for methanol electrooxidation

A key challenge in developing direct methanol fuel cells is the fabrication of electrocatalysts with high activity and long durability. Herein, we report a performance enhanced electrocatalyst of nanoscale Pd on MXene (Ti3C2Tx) and reduced graphene oxide (rGO). The mass activity of Pd/Ti3C2Tx-rGO (1: 1) hybrid toward methanol oxidation reaction is 753 mA mg−1, which is 1.7 times than that of Pd/C (446 mA mg−1). Additionally, the current density of Pd/Ti3C2Tx-rGO (1:1) catalyst contains 212 mAmg−1 which is nine times higher than that of Pd/C (23 mA mg−1) after 7200 s. The Pd/Ti3C2Tx-rGO (1:1) catalyst exhibits excellent cycling stability and long-term life. These remarkable catalytic performances are attributed to the role of Ti3C2Tx and rGO in enhancing the catalytic activity surface area and rapid mass/charge transfer due to the synergistic effect between Pd and Ti3C2Tx/rGO.

Directed Molecular Stacking for Engineered Fluorescent Three-Dimensional Reduced Graphene Oxide and Coronene Frameworks.

Three‐dimensional fluorescent graphene frameworks with controlled porous morphologies are of significant importance for practical applications reliant on controlled structural and electronic properties, such as organic electronics and photochemistry. Here we report a synthetically accessible approach concerning directed aromatic stacking interactions to give rise to new fluorogenic 3D frameworks with tuneable porosities achieved through molecular variations. The binding interactions between the graphene‐like domains present in the in situ‐formed reduced graphene oxide (rGO) with functional porphyrin molecules lead to new hybrids via an unprecedented solvothermal reaction. Functional free‐base porphyrins featuring perfluorinated aryl groups or hexyl chains at their meso‐ and β‐positions were employed in turn to act as directing entities for the assembly of new graphene‐based and foam‐like frameworks and of their corresponding coronene‐based hybrids. Investigations in the dispersed phase and in thin‐film by XPS, SEM and FLIM shed light onto the nature of the aromatic stacking within functional rGO frameworks (denoted rGOFs) which was then modelled semi‐empirically and by DFT calculations. The pore sizes of the new emerging reduced graphene oxide hybrids are tuneable at the molecular level and mediated by the bonding forces with the functional porphyrins acting as the “molecular glue”. Single crystal X‐ray crystallography described the stacking of a perfluorinated porphyrin with coronene, which can be employed as a molecular model for understanding the local aromatic stacking order and charge transfer interactions within these rGOFs for the first time. This opens up a new route to controllable 3D framework morphologies and pore size from the Ångstrom to the micrometre scale. Theoretical modelling showed that the porosity of these materials is mainly due to the controlled inter‐planar distance between the rGO, coronene or graphene sheets. The host‐guest chemistry involves the porphyrins acting as guests held through π‐π stacking, as demonstrated by XPS. The objective of this study is also to shed light into the fundamental localised electronic and energy transfer properties in these new molecularly engineered porous and fluorogenic architectures, aiming in turn to understand how functional porphyrins may exert stacking control over the notoriously disordered local structure present in porous reduced graphene oxide fragments. By tuning the porosity and the distance between the graphene sheets using aromatic stacking with porphyrins, it is also possible to tune the electronic structure of the final nanohybrid material, as indicated by FLIM experiments on thin films. Such nanohybrids with highly controlled pores dimensions and morphologies open the way to new design and assembly of storage devices and applications incorporating π‐conjugated molecules and materials and their π‐stacks may be relevant towards selective separation membranes, water purification and biosensing applications.

Self-assembled nickel anchored reduced graphene oxide hybrids: Synergistic performance of electro-catalyst for oxygen reduction reaction in non-aqueous medium

The recent advances in nanotechnology developing cost-effective, high efficient catalyst for oxygen reduction reaction (ORR). In this paper, we successfully prepared the self- assembled nickel anchored reduced graphene oxide (Ni@RGO) hybrids by in situ reduction method. The formation and structural analysis of the Ni@RGO were carried out by using powder x-ray diffraction (XRD) and Raman spectroscopy. Surface morphology and topography of Ni@RGO hybrids elucidated by scanning electron microscope (SEM) and transmission electron microscope (TEM) analysis. ORR is employed in a non-aqueous electrolyte by using cyclic voltammetry and rotating disk electrode (RDE) technique. The catalytic performances of the Ni@RGO hybrids investigated in non-aqueous Li-O2 cells and it’s subjected to charge-discharge cycling at several current densities. The performance of the Ni@RGO hybrids show that, it is a potential candidate for ORR and also the catalyst for multifunctional applications.

Fabrication of eco-friendly carbon microtubes @ nitrogen-doped reduced graphene oxide hybrid as an excellent carbonaceous scaffold to load MnO2 nanowall (PANI nanorod) as bifunctional material for high-performance supercapacitor and oxygen reduction reaction catalyst

Recently, with the concept of building a resource-conserving and environment-friendly society, the idea of developing green, sustainable and multifunctional materials has become increasingly urgent. So, how to explore more possible ways for efficient and sustainable utilization of biomass resources is very important. In this paper, a novel eco-friendly and sustainable 3D bifunctional carbon microtubes@nitrogen-doped reduced graphene oxide (CMT@N-RGO) hybrid based biomass material is firstly fabricated by combining dipping and chemical vapor deposition methods. Then the CMT@N-RGO hybrid is served as an excellent carbonaceous scaffold for constructing hierarchical hybrid with high-performance in energy storage and electrocatalysis. Finally, we have successfully prepared CMT@N-RGO/MnO2 and CMT@N-RGO/PANI hybrid with good supercapacitive and excellent oxygen reduction reaction (ORR). In short, the as-fabricated hybrid served as electrodes of supercapacitor present fast charge/discharge rate, excellent rate performance, and outstanding capacitance retention of 95% (93%) and high energy efficiency of 65–77% (61–72%) for both. In addition, the hybrid acted as an efficient electrocatalyst in the oxygen reduction reaction shows a larger positive onset potential of −0.12 V and half-wave potential of −0.21 V, which can be comparable to that of commercial Pt/C electrode. The improved capacitive and electrocatalytic properties are mainly attributed to the synergistic effects between the CMT and N-RGO/PANI (MnO2). In a word, these attractive results demonstrate that the 3D CMT@N-RGO/PANI (MnO2) hybrid are promising high-performance bifunctional material for supercapacitors and ORR catalyst. Hopefully, it can open up a versatile way for us to devise and manufacture more various multifunctional biomass-based material with outstanding electrochemical properties, excellent oxygen reduction reaction performance and other outstanding properties.

Programmable Laser Patterning of Ag Nanoparticles and Reduced Graphene Oxide Hybrid Electrodes for Nonenzymatic Hydrogen Peroxide Detection

Graphene and noble metal hybrid electrodes are promising for electrochemical sensing. However, open problems with respect to electrode patterning and integration still restrict their practical appl...

One-step solid state synthesis of facet-dependent contact TiO2 hollow nanocubes and reduced graphene oxide hybrids with 3D/2D heterojunctions for enhanced visible photocatalytic activity

One-step solid state calcination strategy via a template-engaged topotactic transformation process has been developed to construct serials of 3D TiO2 hollow nanocubes (TiO2-HNCs) with 2D reduced graphene oxide (rGO) heterojunction hybrids with facet-dependent contact for the first time. The effect of calcination temperature and TiOF2/GO mass ratio on the morphology and photocatalytic activity of TiO2-HNCs/rGO hybrids was systematically discussed. The study indicated that 3D TiO2 hollow nanocubes were assembled by six regular nanosheets and GO can effectively reduce the solid-state calcination temperature and facilitate the topological transformation from cubic TiOF2 to TiO2-HNCs through 3D/2D heterojunctions hybridized to TiO2-HNCs, which also provided a transferring photo-induced electrons bridge to sensitize TiO2-HNCs for enhancing visible light response. The infrared spectra (IR), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopic studies revealed that rGO principally hybridized on the surface as sp2 graphitic carbon in extended p-π conjugated environments and a small percentage of rGO created carbonate structure by substituted surface Ti atoms in the TiO2-HNCs lattice. Due to the superior sensitization and charge carrier mobility of rGO, the photodegradation activity of Rhodamine B (RhB) of as-prepared T300/5rGO hybrid improved 4.6 times compared to P25 with a degradation yield of 99% within 90 min under simulated sunlight irradiation (>420 nm) and still remained over 95% after 5 recycles. The enhanced photoreactivity of TiO2-HNCs/rGO was mainly attributed to the strong hybridized interaction through chemical bonds between TiO2-HNCs and rGO, which formed 3D/2D facet-dependent contact heterojunctions and further verified by its good dispersibility and stability. The unique facet-dependent contacting rGO with {1 0 1} instead of {0 0 1} facets of TiO2-HNCs facilitated the injection and transfers of photo-induced electrons from {1 0 1} facet of TiO2-HNCs to rGO, thus retarding the recombination of electron-hole pairs, which was not only increasing the numbers of active sites, but also facilitating the adsorption of dye molecules, and improving light-harvesting ability, thereby enhancing visible photoreactivity of TiO2-HNCs/rGO hybrids.

Enhanced polarization of electron-poor/rich micro-centers over nZVCu-Cu(II)-rGO for pollutant removal with H2O2

Nanoscale zero-valent copper combined with Cu(II)-doped reduced graphene oxide hybrid (nZVC-Cu(II)-rGO) is synthesized through an annealing reduction process, and it shows very high activity and efficiency for removing refractory organic compounds with H2O2. The conversion rate for the organic pollutant in this system is ∼77 and ∼13 times higher than that in the graphene oxide (GO) and reduced graphene oxide (rGO) systems, respectively. The characterization shows that nanoscale Cu(0) and Cu(II) are generated on the rGO surface during the annealing process and they are accompanied by the COCu bonding formation between the rGO substrate and the Cu(II) species in nZVC-Cu(II)-rGO, which induces cation–π interactions on the surface, resulting in the reinforced electron-rich micro-centers formation around the nZVC-enhanced Cu(II) species and electron-poor micro-centers on rGO-aromatic rings. The generation of nanoscale Cu(0) consolidates the polarization of the dual reaction micro-centers and greatly accelerates the electron transfer of the system, thus promoting H2O2 reduction to OH in the electron-rich micro-centers. Pollutants can obviously replace H2O2 as the electron donors of the system and are efficiently oxidized and degraded in the electron-poor micro-centers, with their own electron energy being fully utilized in the nZVC-Cu(II)-rGO Fenton-like system.

Laminated microwave absorbers of A-site cation deficiency perovskite La0.8FeO3 doped at hybrid RGO carbon

Laminated hybrid carbon of amorphous carbon and RGO (reduced graphene oxide) perovskite composite, La0.8FeO3/C/RGO-BD, was fabricated by a simple method in one pot. The amorphous carbon was carbonized from d-glucose which also played a role as reducing agent. RGO provided a great condition for the formation of conductive loops. While A-site cation deficiency perovskite La0.8FeO3 doped at carbon nanosheets was induced to adjust the comprehensive microwave absorption properties. The phase and composition characteristics were studied by X-ray diffraction patterns (XRD), Raman and FT-IR spectrums and X-ray photoelectron spectroscopy (XPS), especially the confirmation of the existence of A-site cation deficiency and Oxygen vacancy. The morphology and microstructure of samples were visualized by a scanning electron microscope (SEM) and a transmission electron microscope (TEM). The electromagnetic microwave absorption properties were further studied, as the reflection loss of La0.8FeO3/C/RGO-BD reached −42.69 dB at 8.08 GHz with an effective band 2.72 GHz at 3.15 mm. And the excellent microwave absorption properties were confirmed by impedance matching, one quarter-wavelength theory, Debye relaxation polarization theory and eddy current loss.

Self-aligned TiO2 - Photo reduced graphene oxide hybrid surface for smart bandage application

Abstract A novel hybrid interface of photo-reduced graphene oxide on TiO2 nanotube (TiNT) matrix was developed as a sensing electrode for L-Tyrosine detection towards the development of smart bandage for wound monitoring application, specifically for diabetic foot ulcer (DFUs) patients. The TiNT matrix was developed on titanium (Ti) foil using electrochemical anodization, further; graphene oxide (GO) thin film was electrodeposited on it. This hybrid nanostructure was then photo-reduced using UV light (λ = −290 nm) for 4 min, leading to the conversion of GO to reduced graphene oxide (rGO). The TiNT-rGO hybrid electrode thus formed was further modified with Tyrosinase enzyme for selective detection of tyrosine, which is a bio-marker for DFUs. The sensitivity and limit of detection (LoD) of the developed sensor was found to be 0.106 Ω/nM/cm2 and 0.35 nM respectively, with response time of

Ultrasound-assisted synthesis of α-MnS (alabandite) nanoparticles decorated reduced graphene oxide hybrids: Enhanced electrocatalyst for electrochemical detection of Parkinson's disease biomarker

Herein, novel manganese sulfide nanoparticles (MnS NPs) decorated reduced graphene oxide (rGOS) nanocomposite have been designed through a facile ultrasound-assisted method and followed by a sonication process. After then, as-synthesized α-MnS@rGOS was characterized by HRTEM, FESEM, XPS, XRD and EIS. Furthermore, the α-MnS@rGOS nanocomposite modified SPCE (screen-printed carbon electrode) shows excellent electrochemical sensing performance towards Parkinson’s disease biomarker of dopamine (DA). Moreover, the fabricated sensor showed a wide linear range for dopamine between 0.02 and 438.6 µM and nanomolar detection limit (3.5 nM). In addition, the α-MnS@rGOS modified SPCE showed selectivity towards the detection of dopamine in presence of a 10-fold higher concentration of other important biomolecules. The nanocomposite film modified SPCE sensor was good stable and reproducible towards the detection of Parkinson's disease biomarker. Furthermore, the as-synthesized α-MnS@rGOS nanocomposite modified SPCE has been applied to the determination of dopamine in human serum, rat serum and pharmaceutical samples with acceptable recoveries.