Electrode for Voltammetric Evaluation of Insoluble Particles

A working electrode was developed to test the electrochemical behavior of insoluble particles in aqueous acidic and basic electrolytes.  The hydrogen evolution reaction (HER), oxygen reduction reaction (OER), and pseudocapacitive behavior of nickel phosphide, nickel oxide, and cobalt oxide were evaluated.

The electrode consists of a coiled copper wire in a (55:45 wt. %) mixture of graphite and paraffin wax, housed in either glass or polyvinyl fluoroethylene (PTFE) tubing.  The malleability of the electrode surface allows for particles to be directly embedded into the surface without the use of binder materials such as Nafion or PTFE.  The electrochemical behavior of modified and unmodified electrodes of both the developed carbon-wax electrode and a commercially available glassy carbon electrode (GCE) is presented.  Cyclic voltammetry, linear sweep voltammetry, and chronopotentiometry were employed for electrochemical investigation into the hydrogen evolution reaction, oxygen evolution reaction, and pseudocapacitive behavior of nickel phosphide (NiP₂), nickel oxide (NiO) and cobalt oxide (Co₃O₄) on both working electrode types.   The PTFE electrodes performed well in both acidic and basic media and their performance is comparable to the GCE.  The newly developed electrodes displayed reproducible electrochemical behavior and provide a method to evaluate insoluble particles voltammetrically.