Uncovering the Rate Equation for the Electrochemical Hydrogenation and Hydrogenolysis of Furfural in Acidic Media over Copper

Electrochemical methods can be used to produce chemicals with the benefits of using intermittent renewable electricity and avoiding the use of external hydrogen gas. In addition, electrochemical methods can operate at room temperature and ambient pressure. One process that can be done electrochemically is the electrochemical hydrogenation and hydrogenolysis (ECH) of furfural, a biomass derived species. The hydrogenation and hydrogenolysis products are furfuryl alcohol and 2-methylfuran, respectively, and are produced in parallel. These products are used as a binder and as a fuel, respectively. The kinetics and mechanism of the parallel reactions involved in furfural ECH were investigated and the development of possible mechanisms are presented. The kinetics were investigated by changing the furfural concentration between 10 and 120 mM and the applied potential between -500 and -800 mV vs RHE. In addition, the activation energies were found by changing the temperature between 15°C and 45°C. Three mechanisms are proposed based on the results from changing the concentration of furfural: non-competitive Langmuir-Hinshelwood, competitive Langmuir-Hinshelwood, and Eley-Rideal and their development will be presented.