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Full-Text Articles in Physical Sciences and Mathematics
Quantitative Analysis Of Structure And Bandgap Changes In Graphene Oxide Nanoribbons During Thermal Annealing, Yu Zhu, Xianyu Li, Qinjia Cai, Zhengzong Sun, Gilberto Casillas, Miguel Jose-Yacaman, Rafael Verduzco, James Tour
Quantitative Analysis Of Structure And Bandgap Changes In Graphene Oxide Nanoribbons During Thermal Annealing, Yu Zhu, Xianyu Li, Qinjia Cai, Zhengzong Sun, Gilberto Casillas, Miguel Jose-Yacaman, Rafael Verduzco, James Tour
Yu Zhu
Graphene oxide nanoribbons (GONRs) are wide bandgap semiconductors that can be reduced to metallic graphene nanoribbons. The transformation of GONRs from their semiconductive to the metallic state by annealing has attracted significant interest due to its simplicity. However, the detailed process by which GONRs transform from widebandgap semiconductors to semimetals with a near zero bandgap is unclear. As a result, precise control of the bandgap between these two states is not currently achievable. Here, we quantitatively examine the removal of oxygen-containing groups and changes in the bandgap during thermal annealing of GONRs. X-ray photoelectron spectroscopy measurements show the progressive removal …
Aqueous Dispersions Of Reduced Graphene Oxide And Multi Wall Carbon Nanotubes For Enhanced Glucose Oxidase Bioelectrode Performance, Willo Grosse, Joffrey Champavert, Sanjeev Gambhir, Gordon G. Wallace, Simon E. Moulton
Aqueous Dispersions Of Reduced Graphene Oxide And Multi Wall Carbon Nanotubes For Enhanced Glucose Oxidase Bioelectrode Performance, Willo Grosse, Joffrey Champavert, Sanjeev Gambhir, Gordon G. Wallace, Simon E. Moulton
Gordon Wallace
Aqueous dispersions of reduced graphene oxide (rGO) and multi walled carbon nanotubes (MWCNT) were fabricated through a modified chemical reduction method. The significant advantage of the method developed here is the omission of any stabilising compound or organic solvent to obtain stable rGO-MWCNT dispersions. Significantly biological entities, in this case the enzyme glucose oxidase (GOx), can be successfully incorporated into the dispersion. These dispersions were characterised using XPS, SEM, zeta potential and particle size measurements which showed that the dispersion stability is not sacrificed with the addition of GOx, and significantly, the electrical properties of the rGO and MWCNTs are …
Facile Synthesis Of Reduced Graphene Oxide/Mwnts Nanocomposite Supercapacitor Materials Tested As Electrophoretically Deposited Films On Glassy Carbon Electrodes, Widsanusan Chartarrayawadee, Simon E. Moulton, Chee O. Too, Byung C. Kim, Rao Yepuri, Anthony C. Romeo, Gordon G. Wallace
Facile Synthesis Of Reduced Graphene Oxide/Mwnts Nanocomposite Supercapacitor Materials Tested As Electrophoretically Deposited Films On Glassy Carbon Electrodes, Widsanusan Chartarrayawadee, Simon E. Moulton, Chee O. Too, Byung C. Kim, Rao Yepuri, Anthony C. Romeo, Gordon G. Wallace
Gordon Wallace
This paper reports on a facile synthesis method for reduced graphene oxide (rGO)/multi-walled carbon nanotubes (MWNTs) nanocomposites. The initial step involves the use of graphene oxide to disperse the MWNTs, with subsequent reduction of the resultant graphene oxide/MWNTs composites using l-ascorbic acid (LAA) as a mild reductant. Reduction by LAA preserves the interaction between the rGO sheets and MWNTs. The dispersion-containing rGO/MWNTs composites was characterized and electrophoretically deposited anodically onto glassy carbon electrodes to form high surface area films for capacitance testing. Pseudo capacitance peaks were observed in the rGO/MWNTs composite electrodes, resulting in superior performance with capacitance values up …
Scalable One-Step Wet-Spinning Of Graphene Fibers And Yarns From Liquid Crystalline Dispersions Of Graphene Oxide: Towards Multifunctional Textiles, Rouhollah Jalili, Seyed Hamed Aboutalebi, Dorna Esrafilzadeh, Roderick L. Shepherd, Jun Chen, Sima Aminorroaya-Yamini, Konstantin Konstantinov, Andrew I. Minett, Joselito M. Razal, Gordon G. Wallace
Scalable One-Step Wet-Spinning Of Graphene Fibers And Yarns From Liquid Crystalline Dispersions Of Graphene Oxide: Towards Multifunctional Textiles, Rouhollah Jalili, Seyed Hamed Aboutalebi, Dorna Esrafilzadeh, Roderick L. Shepherd, Jun Chen, Sima Aminorroaya-Yamini, Konstantin Konstantinov, Andrew I. Minett, Joselito M. Razal, Gordon G. Wallace
Gordon Wallace
Key points in the formation of liquid crystalline (LC) dispersions of graphene oxide (GO) and their processability via wet-spinning to produce long lengths of micrometer-dimensional fibers and yarns are addressed. Based on rheological and polarized optical microscopy investigations, a rational relation between GO sheet size and polydispersity, concentration, liquid crystallinity, and spinnability is proposed, leading to an understanding of lyotropic LC behavior and fiber spinnability. The knowledge gained from the straightforward formulation of LC GO "inks" in a range of processable concentrations enables the spinning of continuous conducting, strong, and robust fibers at concentrations as low as 0.075 wt%, eliminating …
Carbon Nanotube-Reduced Graphene Oxide Composites For Thermal Energy Harvesting Applications, Mark S. Romano, Na Li, Dennis Antiohos, Joselito M. Razal, Andrew Nattestad, Stephen Beirne, Shaoli Fang, Yongsheng Chen, Rouhollah Jalili, Gordon G. Wallace, Ray Baughman, Jun Chen
Carbon Nanotube-Reduced Graphene Oxide Composites For Thermal Energy Harvesting Applications, Mark S. Romano, Na Li, Dennis Antiohos, Joselito M. Razal, Andrew Nattestad, Stephen Beirne, Shaoli Fang, Yongsheng Chen, Rouhollah Jalili, Gordon G. Wallace, Ray Baughman, Jun Chen
Gordon Wallace
By controlling the SWNT-rGO electrode composition and thickness to attain the appropriate porosity and tortuosity, the electroactive surface area is maximized while rapid diffusion of the electrolyte through the electrode is maintained. This leads to an increase in exchange current density between the electrode and electrolyte which results in enhanced thermocell performance.
Organic Solvent-Based Graphene Oxide Liquid Crystals: A Facile Route Toward The Next Generation Of Self-Assembled Layer-By-Layer Multifunctional 3d Architectures, Rouhollah Jalili, Seyed Hamed Aboutalebi, Dorna Esrafilzadeh, Konstantin Konstantinov, Simon E. Moulton, Joselito M. Razal, Gordon G. Wallace
Organic Solvent-Based Graphene Oxide Liquid Crystals: A Facile Route Toward The Next Generation Of Self-Assembled Layer-By-Layer Multifunctional 3d Architectures, Rouhollah Jalili, Seyed Hamed Aboutalebi, Dorna Esrafilzadeh, Konstantin Konstantinov, Simon E. Moulton, Joselito M. Razal, Gordon G. Wallace
Gordon Wallace
We introduce soft self-assembly of ultralarge liquid crystalline (LC) graphene oxide (GO) sheets in a wide range of organic solvents overcoming the practical limitations imposed on LC GO processing in water. This expands the number of known solvents which can support amphiphilic self-assembly to ethanol, acetone, tetrahydrofuran, N-dimethylformamide, N-cyclohexyl-2-pyrrolidone, and a number of other organic solvents, many of which were not known to afford solvophobic self-assembly prior to this report. The LC behavior of the as-prepared GO sheets in organic solvents has enabled us to disperse and organize substantial amounts of aggregate-free single-walled carbon nanotubes (SWNTs, up to 10 wt …
Manganosite-Microwave Exfoliated Graphene Oxide Composites For Asymmetric Supercapacitor Device Applications, Dennis Antiohos, Kanlaya Pingmuang, Mark Romano, Stephen Beirne, Tony C. Romeo, Phil Aitchison, Andrew I. Minett, Gordon G. Wallace, Sukon Phanichphant, Jun Chen
Manganosite-Microwave Exfoliated Graphene Oxide Composites For Asymmetric Supercapacitor Device Applications, Dennis Antiohos, Kanlaya Pingmuang, Mark Romano, Stephen Beirne, Tony C. Romeo, Phil Aitchison, Andrew I. Minett, Gordon G. Wallace, Sukon Phanichphant, Jun Chen
Gordon Wallace
Graphene based materials coupled with transition metal oxides are promising electrode materials in asymmetric supercapacitors owing to their unique properties which include high surface area, good chemical stability, electrical conductivity, abundance, and lower cost profile over time. In this paper a composite material consisting of graphene oxide exfoliated with microwave radiation (mw rGO), and manganosite (MnO) is synthesised in order to explore their potential as an electrode material. The composite material was characterised by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to explore …
Cation Exchange At Semiconducting Oxide Surfaces: Origin Of Light-Induced Performance Increases In Porphyrin Dye-Sensitized Solar Cells, Matthew J. Griffith, Kenji Sunahara, Akihiro Furube, Attila J. Mozer, David L. Officer, Pawel Wagner, Gordon G. Wallace, Shogo Mori
Cation Exchange At Semiconducting Oxide Surfaces: Origin Of Light-Induced Performance Increases In Porphyrin Dye-Sensitized Solar Cells, Matthew J. Griffith, Kenji Sunahara, Akihiro Furube, Attila J. Mozer, David L. Officer, Pawel Wagner, Gordon G. Wallace, Shogo Mori
Gordon Wallace
The origin of simultaneous improvements in the short-circuit current density (Jsc) and open-circuit voltage (Voc) of porphyrin dye-sensitized TiO2 solar cells following white light illumination was studied by systematic variation of several different device parameters. Reduction of the dye surface loading resulted in greater relative performance enhancements, suggesting open space at the TiO2 surface expedites the process. Variation of the electrolyte composition and subsequent analysis of the conduction band potential shifts suggested that a light-induced replacement of surface-adsorbed lithium (Li+) ions with dimethylpropylimidazolium (DMPIm+) ions was responsible for an increased electron lifetime by decreasing the recombination with the redox mediator. …
Reduced Graphene Oxide With Superior Cycling Stability And Rate Capability For Sodium Storage, Yunxiao Wang, Shulei Chou, Hua-Kun Liu, S X. Dou
Reduced Graphene Oxide With Superior Cycling Stability And Rate Capability For Sodium Storage, Yunxiao Wang, Shulei Chou, Hua-Kun Liu, S X. Dou
Shi Xue Dou
Sodium ion battery is a promising electrical energy storage system for sustainable energy storage applications due to the abundance of sodium resources and their low cost. In this communication, the electrochemical properties of sodium ion storage in reduced graphene oxide (RGO) were studied in an electrolyte consisting of 1 M NaClO4 in propylene carbonate (PC). The experimental results show that the RGO anode allowed significant sodium ion insertion, leading to higher capacity at high current density compared to the previously reported results for carbon materials. This is due to the fact that RGO possesses higher electrical conductivity and is a …
A Facile Route To Synthesize Transition Metal Oxide/Reduced Graphene Oxide Composites And Their Lithium Storage Performance, Chongjun Zhao, Shulei Chou, Yunxiao Wang, Cuifeng Zhou, Hua-Kun Liu, S X. Dou
A Facile Route To Synthesize Transition Metal Oxide/Reduced Graphene Oxide Composites And Their Lithium Storage Performance, Chongjun Zhao, Shulei Chou, Yunxiao Wang, Cuifeng Zhou, Hua-Kun Liu, S X. Dou
Shi Xue Dou
Transition metal oxide (Mn3O4, Fe2O3, Co3O4, and ZnO) and reduced graphene oxide (RGO) composites were successfully synthesized via a hydrothermal method using the direct reaction between the corresponding metal powder and graphene oxide (GO). In this process, the GO can be reduced by transition metal powder in water, and the nanosized metal oxide can be obtained, and homogeneously mixed with and wrapped by RGO to form a metal oxide/RGO composite at the same time. X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning and transmission electron microscopy were used to characterize the as-prepared materials. The different experimental parameters, including reactants, …
The Electrochemical Properties Of High-Capacity Sulfur/Reduced Graphene Oxide With Different Electrolyte Systems, Yunxiao Wang, Shulei Chou, Hua-Kun Liu, S X. Dou
The Electrochemical Properties Of High-Capacity Sulfur/Reduced Graphene Oxide With Different Electrolyte Systems, Yunxiao Wang, Shulei Chou, Hua-Kun Liu, S X. Dou
Shi Xue Dou
The lithium/sulfur battery is a promising electrochemical system with high capacity, which is well-known to undergo a complex multistep reaction during the discharge process. Two types of electrolytes including poly (ethylene glycol) dimethyl ether (PEGDME)-based and 1.3 - dioxolane (DOL)/ dimethoxyethane (DME)-based electrolytes were investigated here. Furthermore, LiNO3 additive was introduced into the electrolyte in order to effectively eliminate the overcharge effect. The lithium sulfur battery with 1.0 M LiN(CF3SO2)2 in PEGME with 0.1 M LiNo3 shows highly stable reversible capacity of 624.8 mAh g-1 after 200 cycles and improved average coulombic efficiency of 98 percent.