Graphene Oxide Composite Electrode Research Articles

Determination of some neurotransmitters at cyclodextrin/ionic liquid crystal/graphene composite electrode

A novel reduced graphene oxide (RGO) composite glassy carbon electrode modified with ionic liquid crystal (ILC), 1-Butyl-1-methylpiperidinium hexa-fluoro-phosphate and cyclodextrin (CD/ILC/RGO/ILC/GC) was fabricated via mechanical casting of each layer. The modified electrode was used for the determination of some neurotransmitters such as dopamine (DA), epinephrine (EP), norepinephrine (NEP), levodopa (L-DOPA), 3,4-dihydroxy-phenyl acetic acid (DOPAC) and serotonin (ST). This electrode anticipated the good electron mobility and large surface area of graphene, high ionic conductivity and stability of ionic liquid crystal besides the pre-concentrating effect of CD. Optimization of the sensor performance is presented and resulted in a better current signal. The linear dynamic range of the modified electrode was from 0.8×10−7–0.1×10−4molL−1 for determination of EP with a correlation coefficient 0.998 and LOD 0.0117×10−9molL−1. The sensor was sensitive and successfully applied for direct determination of EP in human urine samples with good recovery results.

Fabrication of ultra-high energy and power asymmetric supercapacitors based on hybrid 2D MoS2/graphene oxide composite electrodes: a binder-free approach

Two-dimensional (2D) materials, graphene oxide (GO) and layered molybdenum disulfide (MoS2) nanosheets composite have been potentially investigated as novel energy storage materials due to their unique physicochemical properties.

High rate performance of a NaTi2(PO4)3/rGO composite electrode via pyro synthesis for sodium ion batteries

The present study reports a highly rate capable NASICON-structured NaTi2(PO4)3/reduced graphene oxide (NTP/rGO) composite electrode synthesized by polyol-assisted pyro synthesis for Na-ion batteries (NIBs).

Reduced graphene oxide and polypyrrole/reduced graphene oxide composite coated stretchable fabric electrodes for supercapacitor application

The advent of self-powered functional garments has given rise to a demand for stretchable energy storage devices that are amendable to integration into textile structures. The electromaterials (anode, cathode and separator) are expected to sustain a deformation of 3% to 55% associated with body movement. Here, we report a stretchable fabric supercapacitor electrode using commonly available nylon lycra fabric as the substrate and graphene oxide (GO) as a dyestuff. It was prepared via a facile dyeing approach followed by a mild chemical reduction. This reduced graphene oxide (rGO) coated fabric electrode retains conductivity at an applied strain of up to 200%. It delivers a specific capacitance of 12.3Fg−1 at a scan rate of 5mVs−1 in 1.0M lithium sulfate aqueous solution. The capacitance is significantly increased to 114Fg−1 with the addition of a chemically synthesized polypyrrole (PPy) coating. This PPy-rGO-fabric electrode demonstrates an improved cycling stability and a higher capacitance at 50% strain when compared to the performance observed with no strain.

Superior lithium storage performance using sequentially stacked MnO2/reduced graphene oxide composite electrodes.

Hybrid nanostructures based on graphene and metal oxides hold great potential for use in high-performance electrode materials for next-generation lithium-ion batteries. Herein, a new strategy to fabricate sequentially stacked α-MnO2 /reduced graphene oxide composites driven by surface-charge-induced mutual electrostatic interactions is proposed. The resultant composite anode exhibits an excellent reversible charge/discharge capacity as high as 1100 mA h g(-1) without any traceable capacity fading, even after 100 cycles, which leads to a high rate capability electrode performance for lithium ion batteries. Thus, the proposed synthetic procedures guarantee a synergistic effect of multidimensional nanoscale media between one (metal oxide nanowire) and two dimensions (graphene sheet) for superior energy-storage electrodes.

Electrodeposition of palladium and reduced graphene oxide nanocomposites on foam-nickel electrode for electrocatalytic hydrodechlorination of 4-chlorophenol

A high-performance palladium (Pd) and reduced graphene oxide (RGO) composite electrode was prepared on foam-nickel (foam-Ni) via two-step electrodeposition processes. The scanning electron microscopic (SEM) observation showed that the obtained Pd/RGO/foam-Ni composite electrode displayed a uniform and compact morphology. The X-ray diffraction (XRD) and X-ray photoelectron spectroscopic (XPS) analysis confirmed the successful deposition of Pd and RGO on nickel substrate. The cyclic voltammetric (CV) measurements indicated that the presence of RGO greatly enhanced the active surface area of Pd particles deposited on foam-Ni. The as-deposited Pd/RGO/foam-Ni electrode was applied to electrocatalytic hydrodechlorination (ECH) of 4-chlorophenol (4-CP). Various factors influencing the dechlorination of 4-CP such as dechlorination current, initial concentration of 4-CP, Na2SO4 concentration and initial pH were systematically investigated. The thermodynamic analysis showed that the dechlorination reaction of 4-CP at different temperatures followed the first-order kinetics and the activation energy for 4-CP dechlorination on Pd/RGO/foam-Ni electrode was calculated to be 51.96kJmol−1. Under the optimum conditions, the dechlorination efficiency of 4-CP could reach 100% after 60-min ECH treatment. Moreover, the prepared Pd/RGO/foam-Ni composite electrode showed good stability for recycling utilization in ECH of 4-CP.

An Alumina-Coated Fe3O4-Reduced Graphene Oxide Composite Electrode as a Stable Anode for Lithium-ion Battery

Fe3O4-reduced graphene oxide (rGO) composites have been synthesized via an ethylene glycol-mediated solvothermal-polyol method. The electrochemical performances of the as-prepared Fe3O4-rGO electrode and alumina (Al2O3) film coated Fe3O4-rGO electrode using atomic layer deposition (ALD) were investigated. The results indicated that the ALD coating of Al2O3 greatly improved the electrochemical properties (especially cycling stability) of Fe3O4-rGO composite electrode as an anode for lithium-ion battery (LIB), resulting in the increase of reversible capacity from 94.1mAhg−1 to 717.4mAhg−1 after 200 cycles. The Al2O3 films retain sufficiently integral to limit the excessive growth of the interfacial layer between Fe3O4 and electrolyte, which in turn improves the electrochemical kinetics at the electrode/electrolyte interface and maintains a relatively stable interfacial resistance during whole discharge/charge cycles. The results presented in this study pave a new way to improve the stability of nanostructured anodes for LIBs.

Synthesis and electrochemical performance of Co3O4/graphene

Co3O4/reduced graphene oxide composites were synthesized via a simple electrochemical method from graphene oxide and Co(NO3)2·6H2O as raw materials. Co3O4 nanoparticles with sizes of around 30–50 nm were distributed on the surface of graphene nanosheets confirmed by scanning electron microscopy and transmission electron microscopy. Electrochemical properties of Co3O4/graphene composite were tested by cyclic voltammetry, galvano-static charge-discharge, and electrochemical impedance spectroscopy. The Co3O4/reduced graphene oxide composite was used as the pseudocapacitor electrode in the 2 mol/L NaOH aqueous electrolyte solution. The Co3O4/reduced graphene oxide composite electrode exhibited a specific capacitance of 357 F/g at a current density of 0.5 A/g in a three-electrode system. 72% of capacitance was retained when the current density increased to 3 A/g. The Co3O4/reduced graphene oxide composite prepared electrodes show a high rate capability and excellent long-term stability. After 1000 cycles of charge and discharge, the capacitance is still maintained 87% at a current density of 1 A/g, indicating that the composite is a promising alternative electrode material used for supercapacitors.

Performance enhancement of single-walled nanotube–microwave exfoliated graphene oxide composite electrodes using a stacked electrode configuration

Optimised SWNTs/MW-rGO supercapacitor in a stacked electrode configuration, leading to an enhancement of energy density.

MoO2/Reduced Graphene Oxide Composite Electrode with Improved Cycling Performance and High Capacitance for Supercapacitors

MoO₂/Reduced Graphene Oxide Composite Electrode with Improved Cycling Performance and High Capacitance for Supercapacitors

Efficiency Characteristics of Dye-Sensitized Solar Cells (DSSCs) by Incorporation of TiO2-Reduced Graphene Oxide Composite Electrodes

We successfully fabricated the TiO2-based photoelectrode doped with reduced graphene oxide (rGO) to improve the power conversion efficiency of dye-sensitized solar cells (DSSCs). The ratio of rGO was 0.3∼1.5 wt%. The DSSCs with the TiO2 photoanode incorporated 0.3 wt% rGO showed a maximum power conversion efficiency of 6.26% which is 44% higher than the pristine TiO2 photoelectrode. We concluded the introduction of rGO doped at 0.3 wt% ratio contributed to reducing the resistance of the surface and the interface of the photoelectrode from the observation of electrochemical impedance spectroscopy(EIS).