Aqueous electrocatalytic hydrogenation of furfural using a sacrificial anode

Abstract

Electrocatalytic hydrogenation (ECH) of furfural to furfuryl alcohol and 2-methylfuran was studied. Experiments were run in an undivided cell in aqueous solution with a sacrificial Ni or Ni–Fe alloy anode. Aluminum (Al), iron (Fe), nickel (Ni), copper (Cu), and stainless steel (SS) 308 were used as cathode materials. As expected, the cathode metal, which serves as the hydrogenation catalyst, was found to have a large effect on the ECH of furfural. Among the cathode metals studied, the Ni and Fe cathodes gave the greatest product yield and electrochemical efficiency. Effects of electrolyte solution pH on product yield and electrochemical efficiency were also investigated. The yield of furfuryl alcohol was highest at pH 5.0, while that of 2-methylfuran was favored at pH 1.0. To differentiate between the catalytic roles of the original cathode material and the Ni being dynamically deposited on the cathode by reduction of anode-derived Ni ions, ECH of furfural in a divided cell was compared with that in the undivided cell. Without pre-electrolysis during electrocatalytic hydrogenation of furfural, both the original cathode material and the deposited nickel contributed to the catalytic effect. The initial furfural concentration and the current density also strongly affected the product yield and electrochemical efficiency.