Strong Electronic Coupling of Graphene Nanoribbons onto Basal Plane of Glassy Carbon Electrode

Abstract

The electrochemical behavior of graphene nanoribbons deposited onto glassy carbon electrode using pi-stacking interactions was investigated. We illustrate here that strong electronic communication could be achieved with basal plane of glassy carbon using simple electrochemical treatment.

Interfacial Electrochemistry of Catalyst-Coordinated Graphene Nanoribbons

“…Our assignment for bpm electrochemistry was thus slightly modified from our original work, where only two distinct pH regions were identified. 57 The updated model presented here is more consistent with additional theoretical modeling and SEC results.…”

“…The cathodic-to-anodic peak-to-peak separation observed in GNR-2DNS varied between 30-50 mV, indicating a small kinetic barrier associated with the observed charge transfer process and strong electronic coupling of GNR-2DNS with the glassy carbon electrode. In our previous study, 57 we observed similar "strongly coupled" responses for GNR samples drop-casted onto the electrode surface. However, in the previous study, electrochemical pre-treatment was required to disperse the "weakly-coupled" GNR aggregates and form GNR monolayers in strong electronic communication with the electrode.…”

“…56 In a previous study, we took advantage of the redox-active nitrogen functionality to investigate the electrochemical behavior of immobilized GNRs. 57 We found that the PCET of immobilized GNRs deviated from that observed for a homogeneous model compound, bipyrimidine (bpm), indicating that the interfacial electric fields modulate the electrochemical behavior of GNRs. In this study, we investigated the electrochemical behavior of GNR 2D nanosheets (GNR-2DNS) and Rhcoordinated GNR 2D nanosheets (RhGNR-2DNS) and its activity towards the HER.…”

“…This PCET slope has been very useful in studies of PCET in homogeneous systems, as it reports on the relative ratio m/n, providing information on the number of electrons and protons transferred during PCET. 36,57,71 In our case, we used the slopes observed for bpm to assign three PCET processes taking place in three pH regions: bpm/bpmH4 2+ Unlike the behavior of GNR-2DNS, CVs of RhGNR-2DNS films reveal two reversible, and partially overlapping, features across the entire aqueous pH region (Figure 2, red traces). We assigned these two reduction features to PCET at bipyrimidine moieties that are either uncoordinated (feature 1, peaks that appear at the same potential as GNR-2DNS at all pHs) or Rhcoordinated (feature 2, peaks appear at more positive potentials, due to the electron-withdrawing s-acceptor nature of Rh-atoms).…”