The electrocatalyst was suspended in an equal volume solution of ethanol and water so that the concentration was 1 mg of catalyst per mL of 1:1 ethanol:water mixture. After ultrasonication to disperse the electrocatalyst in the 1:1 ethanol:water mixture, 25mg of electrocatalyst was suspended drop-wise on a Pt rotating disk electrode (RDE); the ethanol:water solution was evaporated by gently heating the Pt RDE in a typical laboratory oven at 70 C until only the electrocatalyst remained on the disk. Electrochemical measurements were conducted in a standard three-electrode
beaker cell, with the Co core/Pt partial shell alloy electrocatalyst as the working electrode. A Hg/HgO electrode served as the reference, and a Pt ring positioned 2 cm away from the working electrode served as the counter electrode. Although the reference
electrode was Hg/HgO, the potentials were later referenced against
the standard hydrogen electrode (SHE) for analysis and reported as
such in this work. The electrochemical experiments were conducted at room temperature and under atmospheric conditions.
Cyclic voltammetry was conducted in 1MKOH at 0.05 V/s in the
absence of lignin as a background. Next, lignin was added to the
alkaline solution so that its concentration was 10 g of lignin per
liter, and cyclic voltammetry was conducted at scan rates ranging
from 0.05 V/s to 0.5 V/s. Then, the RDE with the Co core/Pt partial
shell electrocatalyst was rotated from 200 rpm to 1700 rpm and the
potential of the working electrode was scanned for kinetic studies.
Finally, the working electrode potential was held constant at
0.598 V vs. SHE, and solution was periodically pipetted and stored
in a vial to identify oxidation products via GCeMS.