Direct Voltammetric Detection of DNA and pH Sensing on Epitaxial Graphene: An Insight into the Role of Oxygenated Defects

Lim, Cheng Xiang; Hoh, Hui Ying; Ang, Priscilla Kailian; Loh, Kian Ping

doi:10.1021/ac101519v

Cited by 236 publications

(223 citation statements)

References 34 publications

(46 reference statements)

Supporting

Mentioning

212

Contrasting

Unclassified

Order By: Relevance

“…Pristine graphene shows excellent in-plane electrical conductivity. However, because of the anisotropic nature of its electron delocalization, it is known to be electrochemically sluggish for charge transfer in the direction normal to its basal plane 22 . An exception is found, however, in the case of GNB, because its strained surfaces means that the flatlying 2p orbitals are distorted, and midgap states will be created to which enhanced charge transfer can occur.…”

Section: Gnbs On Diamondmentioning

confidence: 99%

A hydrothermal anvil made of graphene nanobubbles on diamond

et al. 2013

Self Cite

View full text Add to dashboard Cite

The hardness and virtual incompressibility of diamond allow it to be used in high-pressure anvil cell. Here we report a new way to generate static pressure by encapsulating singlecrystal diamond with graphene membrane, the latter is well known for its superior nanoindentation strength and in-plane rigidity. Heating the diamond-graphene interface to the reconstruction temperature of diamond (B1,275 K) produces a high density of graphene nanobubbles that can trap water. At high temperature, chemical bonding between graphene and diamond is robust enough to allow the hybrid interface to act as a hydrothermal anvil cell due to the impermeability of graphene. Superheated water trapped within the pressurized graphene nanobubbles is observed to etch the diamond surface to produce a high density of square-shaped voids. The molecular structure of superheated water trapped in the bubble is probed using vibrational spectroscopy and dynamic changes in the hydrogen-bonding environment are observed.

show abstract

Section: Gnbs On Diamondmentioning

confidence: 99%

A hydrothermal anvil made of graphene nanobubbles on diamond

et al. 2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…Due to rather poor electrocatalytic activity of intrinsic graphene and graphite [25][26][27], the electrodes were activated by anodization [28,29]. It has been shown that during electrochemical oxidation, several functional groups connect to the graphite basal plane and many multivacancies and small etch pits appear [30].…”

Section: Introductionmentioning

confidence: 99%

Insights into electrocatalytic activity of epitaxial graphene on SiC from cyclic voltammetry and ac impedance spectroscopy

Szroeder¹,

Tsierkezos

Walczyk³

et al. 2014

J Solid State Electrochem

View full text Add to dashboard Cite

Electrocatalytic activity of graphene grown epitaxially on SiC is studied using cyclic voltammetry and electrochemical impedance spectroscopy. AFM images show steplike topography of SiC-graphene. For ferri-/ferrocyanide redox couple, no voltammetric response is observed at the pristine graphene. Basal planes of graphite are electrochemically inactive as well. After electrochemical oxidation, apparent redox peaks appear at both the graphene and graphite electrode. However, more intensive redox peaks are observed at graphene, where simultaneous redox reaction with the adsorbed and the diffused ferri-/ferrocyanide ions occurs. Electrochemical impedance measurements show that the graphene electrode behaves like an array of microelectrodes. We used the partially blocked electrode model to fit impedance data. Using the fitting parameters, a size of microelectrodes was found to be 23.8±2.1 μm and the active surface of graphene was estimated to be 21 %. A value of the standard electron transfer rate constant found for the anodized epitaxial graphene (2.16±0.32)×10) is by one order of magnitude lower than the standard rate constant estimated for the anodized graphite basal planes (∼5 × 10 − 2 cm ⋅ s − 1 ).Electrochemical reduction causes total disappearance of electrochemical responses at the graphene electrode, whereas only slight decrease of the peak currents is observed at the reduced graphene. Such behavior proves that different activation mechanisms occur at the graphene and graphite electrodes.

show abstract

“…Detailed HET studies on uorinated graphene oxide (FGO) (a functional derivative of FG, containing various oxygen functionalities) and reduced uorinated graphene oxide (RFGO) were conducted for the rst time with a negatively charged redox molecule namely [Fe(CN) 6 several other factors such as conductivity (way of synthesis), percentage and nature of defects, presence of functionalities, orientation and presence of other elements. 18,19 Graphene oxide (GO), which is an oxygen rich functional derivative of graphene, 20 is considered as a base material for the bulk synthesis of graphene by various reduction methods. However, graphene produced by this method may contain residual functional groups and defects such as Stone-Wales type, 21 and these can alter the resultant HET process.…”

mentioning

confidence: 99%

“…24 Though there are some contradictory arguments on the role of functional groups on the carbon process in HET, this enhanced electron transfer in the case of reduced systems may be due to the reduced negative charge and enhanced electronic conductivity. 26,20 However, no study has been conducted so far to correlate the conductivity of Moreover, the HET process was simulated using Digielch 7 professional V7 soware. Here, experimental parameters were used to simulate the CV for the four samples (GO, FGO, RGO and RFGO) and tted with the faradaic portion of the experimental data.…”

mentioning

confidence: 99%

Improved heterogeneous electron transfer kinetics of fluorinated graphene derivatives

Boopathi

Narayanan

2014

Nanoscale

View full text Add to dashboard Cite

Though graphitic carbons are commercially available for various electrochemical processes, their performance is limited in terms of various electrochemical activities. Recent experiments on layered carbon materials, such as graphene, demonstrated an augmented performance of these systems in all electrochemical activities due to their unique electronic properties, enhanced surface area, structure and chemical stabilities. Moreover, flexibility in controlling electronic, as well as electrochemical activities by heteroatom doping brings further leverage in their practical use. Here, we study the electron transfer kinetics of fluorinated graphene derivatives, known as fluorinated graphene oxide (FGO) and its reduced form, RFGO. Enhanced electron transfer kinetics (heterogeneous electron transfer (HET)) is observed from these fluorinated systems in comparison to their undoped systems such as graphene oxide (GO) and reduced GO. A detailed study has been conducted using standard redox probes and biomolecules revealing the enhanced electro-catalytic activities of FGO and RFGO, and electron transfer rates are simulated theoretically. This study reveals that fluorine not only induces defects in graphitic lattice leading to an enhanced HET process but also can modify the electronic structure of graphene surface.

show abstract

Direct Voltammetric Detection of DNA and pH Sensing on Epitaxial Graphene: An Insight into the Role of Oxygenated Defects

Cited by 236 publications

References 34 publications

A hydrothermal anvil made of graphene nanobubbles on diamond

A hydrothermal anvil made of graphene nanobubbles on diamond

Insights into electrocatalytic activity of epitaxial graphene on SiC from cyclic voltammetry and ac impedance spectroscopy

Improved heterogeneous electron transfer kinetics of fluorinated graphene derivatives

Contact Info

Product

Resources

About