Single graphene nanoplatelets: capacitance, potential of zero charge and diffusion coefficient

Abstract

A nano-impact chronoamperometric experiment is presented here as a powerful technique for simultaneously probing important physical properties of graphene nanomaterials.

Nanoimpacts Reveal the Electron‐Transfer Kinetics of the Ferrocene/Ferrocenium Couple Immobilised on Graphene Nanoplatelets

“…Upon collisions between a GNP and the electrode, two possible types of charge transfer take place, resulting in impact spikes, namely, capacitative and faradaic. The physical origin of the two types of processes has been elaborated in earlier work . The black lines in Figure show that Q for unmodified GNPs increases slightly, only around 1.5 pC upon elevation of the applied potential from +0.30 to +1.00 V, indicating that it follows capacitative behaviour.…”

“…The physical origin of the two types of processes has been elaborated in earlier work . The black lines in Figure show that Q for unmodified GNPs increases slightly, only around 1.5 pC upon elevation of the applied potential from +0.30 to +1.00 V, indicating that it follows capacitative behaviour. In contrast, the red lines in Figure demonstrates a sharp increase of approximately 57 pC in Q for PVFc–GNPs between +0.30 and +1.00 V. This likely corresponds to faradaic impacts arising from the oxidation of PVFc adsorbed on the GNPs.…”

“…All chemicals were provided by Sigma–Aldrich (St Louis, MO, USA) at reagent level, unless stated below. The GNPs (width of 15 μm, thickness of 7 nm, estimated from scanning electron microscopy) were purchased from Strem Chemicals (Newburyport, MA, USA). PVFc was purchased from Polyscience Inc. (Warrington, PA, USA).…”

Probing Dynamic Events of Dielectric Nanoparticles by a Nanoelectrode‐Nanopore Nanopipette

“…[17][18][19][20][21] Previously, we have demonstrated how a new nanoporenanoelectrode dual-barrel nanopipette based method can detect both the ionic current and potential change induced by the translocation of individual gold NPs (GNPs) through the nanopore. [23][24][25] The capacitance change is difficult to detect when the NP size is smaller than 100 nm. This is different from the capacitive signal, which is induced by the disturbance of the electrical double layer (EDL) near electrode surface by NP collision events.…”

Impact Electrochemistry: Detection of Graphene Nanosheets Labeled with Metal Nanoparticles through Oxygen Reduction Mediation

“…Graphene is difficult to oxidize/reduce and it is not particularly electrocatalytic for many reactions. Multilayer graphene sheets were recently detected by using impact electrochemistry through the disturbance of the double layer . In another work, graphene sheets were labeled with derivatized ferrocene and they were detected by using chronoamperometry, producing typical spikes upon impact .…”