Design of an Electrochemical Cell for Continuous Wave EPR Measurements of Radical Ions

The combination of continuous wave electron paramagnetic resonance (cw‐EPR) with electrochemistry is highly attractive as it allows a clean in‐situ generation and the subsequent spectroscopic characterisation of radical ions, which are important intermediates in many photocatalytic cycles as well as light‐induced processes occurring in biological systems or optoelectronic devices. Although commercial setups for spectroelectrochemical EPR are available, they are often expensive and tailored to a particular spectroscopic setup. Here we present a design for a low‐cost electrochemical EPR cell that can be used in combination with any commercial cw‐EPR instrumentation. The cell design is compared to existing setups and the performance of the cell is evaluated by comparison of EPR spectra obtained by chemical and electrochemical oxidation of a graphene fragment.