Modification of conductive electrodes with chemically tunable molecular catalysts represents an interesting and relatively unexplored area of electrocatalysis research. Here, we report an investigation of the electrochemical behavior of graphene nanoribbons (GNR) deposited onto a glassy carbon electrode using π−π stacking interactions. Using the bipyrimidine moiety on the nanoribbon edges as a reporter of the proton-coupled electron transfer chemistry, we illustrate that the simple electrochemical treatment of as-deposited nanoribbon generates a hybrid material that is in strong electronic communication with the conductive support.¹ This work shows a strategy for modifying the basal plane of carbon materials and provides a potential platform for the incorporation of catalytic metal sites via coordination through the N-functionalities of GNR.

We also investigate the coordination of Rh-based hydrogen evolution reaction catalyst onto the edges of GNRs to form metal-nanoribbon catalyst (Rh-GNR). The electrocatalytic hydrogen evolution reaction was observed when glassy carbon electrode is modified by Rh-GNR to form Rh-GNR@GC (manuscript in preparation). The catalytic activity is maintained throughout the entire pH region, which contrasts the behavior of the homogeneous (molecular) analog catalyst. The Rh K-edge X-ray absorption spectroscopy reveals that the molecular analog and Rh-GNR exhibit identical coordination environment, indicating that the differences in electrochemical behavior do not arise due to functional group differences between the two catalysts. The observed change in catalytic mechanism is constituent with strong electronic coupling between the carbon electrode and Rh-GNRand our results are discussed in terms of field-driven chemistry.

(1) Zoric, M. R.; Askins, E. J.; Qiao, X.; Glusac, K. D. Strong Electronic Coupling of Graphene Nanoribbons onto Basal Plane of a Glassy Carbon Electrode. ACS Appl. Electron. Mater. 2021, 3 (2), 854-860.

Erik Askins

Appearances