Structure-Dependent Electrochemistry of Reduced Graphene Oxide Monolayers

Abstract

While graphene and other carbonaceous nanomaterials have shown promise in a variety of electrochemical applications, measurement of their intrinsic performance is often confounded with effects related to the complexities due to diffusion in a porous medium. To bypass this limitation, we use effectively non-porous tiled monolayers of reduced graphene oxide as a model platform to study how rates of heterogeneous electron transfer evolve as a function of graphene structure/chemistry. A variety of electrochemical systems are investigated including the standard ferri/ferrocyanide redox probe, several common biomolecular redox systems as well as copper electrodeposition. We show that the rates of heterogeneous electron transfer can vary by as much as 3 orders of magnitude depending on the reduction or annealing conditions used and the redox system investigated. Performance changes are linked to graphene chemistry, and we show that the graphene oxide reduction procedure must be chosen judiciously to maximize the electrochemical performance for particular applications.

Electron Transfer to Decorated Graphene Oxide Particles

“…Punckt et al. investigated the effect of the reduction degree of GO upon the HET rate for the [Fe(CN) 6 ] 4−/3− couple in aqueous solution by electrochemical impedance spectroscopy . However, the accurate assessment of the rate of HET is challenging if, as is usual, it is measured from an ensemble of particles, since the response is that from a layer of GO particles cast onto an electrode surface from which it is impossible to deconvolute effects due to the heterogeneity of the sample and the uncertainty of the inter‐particle contact resistance.…”

Graphene material preparation through thermal treatment of graphite oxide electrochemically synthesized in aqueous sulfuric acid

“…11,18 GO can be thermally reduced by shock treatment at the temperatures higher than 1000 C in air or argon atmosphere [19][20][21][22] or by gradual heating under the inert gas ow (nitrogen or argon). 9,23 To remove all oxygen functionalities from the graphitic structure, thermal treatment of GO should be carried out in the presence of hydrogen. 17 On much less scale TRGO is produced by microwave assisted treatment of GO.…”

Atmospheric Plasma Treatment Enhances the Biosensing Properties of Graphene Oxide-Silver Nanoparticle Composite

“…Therefore, the capacitive behavior was observed to be enhanced in rGO SPCE. 31 The oxygen content in GO affects the electrical conductivity, hence removal of the oxygen functional group in rGO increases the conductivity. 30 Moreover, the increase in oxidation peak signifies the increase in the active sites on basal plane of graphene.…”

“…This electrochemical activity enhancement of rGO-AgNPs composites toward cortisol is a result of the improved effective AgNPs sites formed on the surface area of rGO. 31,35 The peak current increase in the presence of cortisol than that of PBS can be due to the reduction of cortisol molecules traces adsorbed on rGO-AgNPs surface. 36 As these modified SPCEs showed the effective detection of cortisol, they were used to detect the different concentrations of cortisol to study the physisorption of cortisol molecules on surface AgNPs of rGO.…”