Electrocatalytic reduction of furfural for selective preparation of 2-methylfuran over a trace Ni assisted Cu catalyst

Abstract

The electrocatalytic reduction (ECR) of furfural (FF) for the synthesis of 2-methylfuran (MF) with high octane number and calorific value is investigated, using a carbon-paper-supported Ni–Cu bimetallic material as a catalytic electrode. It is found that the Cu in the electrode plays a basic role in the generation of MF from the ECR of FF, while the existence of Ni in a trace amount can remarkably enhance the activity of the Cu electrode. A low pH value is more favorable for the generation of MF than for the formation of furfuryl alcohol (FA). At the optimal pH value of 0.5, the Faradaic efficiency (FE) and the production rate of MF first increase with an increase in current density and then decline after 10 mA cm⁻². The existence of Ni²⁺ in the electrolyte benefits the formation of MF, while the addition of Cu²⁺ ions is more useful to promotion of the generation of FA. At the optimal concentration of Ni²⁺ (10⁻⁷ M) in the electrolyte, the total FE of the organics (88%), the FE of MF (82%) and the production rate of MF (77 μmol cm⁻² h⁻¹) reach their highest levels. Kinetic analysis shows that the route by which MF is directly generated from FF is preferable to a consecutive route with an intermediate of FA.