In situ surface enhanced Raman spectroscopy study of electrode–polyelectrolyte interfaces

Abstract

As polyelectrolytes play a more and more important role in electrochemical fields, further understanding of the electrode–polyelectrolyte interface is in high demand. Surface-enhanced Raman spectroscopy (SERS) is utilized widely in electrode–solution interface research due to its ultra-high sensitivity, but is still rarely in the study of the electrode–polyelectrolyte interface due to difficulties in constructing appropriate electrochemical in situ devices. Additionally, the reported electrochemical in situ Raman works on the electrode–polyelectrolyte interface have a common problem of the coexistence of electrode–solution interfaces and electrode–polyelectrolyte interfaces. Here, we used screen printing electrodes (SPE) with a compact planar three-electrode structure to carry out a new electrochemical in situ SERS test method, which was suitable for the study of the electrode–polyelectrolyte interface. Polyelectrolyte membranes can be conveniently and closely coated on the SPE’s planar three electrodes to achieve isolated electrode–polyelectrolyte interfaces without electrode–solution interfaces coexisting. Strongly potential-dependent signals were obtained from the Pt–Nafion™ interface directly across the Nafion™ membrane, which verifies that this method is practical for the electrochemical in situ SERS study of the electrode–polyelectrolyte interface.