Kinetics and mechanism for electrochemical ammoxidation of furfural to biomass-derived nitrile over CoSe electrocatalyst

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2024-04, Vol.486, p.150039, Article 150039
• Main Authors: Xu, Zhongmou, Chen, Jinzhu
• Format: Article
• Language: English
• Subjects: Ammoxidation; Biomass; Butler-Volmer equation; Concentration−time integral; Kinetics
• ISSN: 1385-8947
• DOI: 10.1016/j.cej.2024.150039

Kinetics and mechanism investigation were performed on electrochemical ammoxidation of furfural to biomass-derived nitrile over CoSe. [Display omitted] •Biomass-based nitrile is obtained by electrochemical ammoxidation with CoSe.•Reversible furfural/NH3 condensation is rds with E as driven force.•Increasing η for anodic oxidation leads to decreased EA and enhanced ka.•CoSe prefers imine oxidation instead of aldehyde oxidation in Helmholtz layer.•Two Co sites synergistically promote redox and Lewis acid-catalyzed process. CoSe was developed as an efficient electrocatalyst for ammoxidation of furfural (1a) and aqueous ammonia to 2-furonitrile (3a) with in-situ formed furfurylimine (2a) as an intermediate. Kinetic investigation, based on concentration − time integral, demonstrated that the reversibly “slow” equilibrium of 1a/NH3-to-2a condensation is shifted to 3a side by the consecutively “quick” reaction of electrochemical 2a-to-3a dehydrogenation with electrolytic voltage as the driven force. Subsequent kinetic analysis of electrochemical 2a-to-3a dehydrogenation over CoSe, based on the Butler-Volmer equation, quantitatively revealed decreased apparent kinetic activation energies and enhanced rate constants with the increasing applied overpotential for the anodic oxidation. The CoSe anode prefers 2a oxidation instead of 1a oxidation in the Helmholtz layer, leading to a selective formation of 3a. The mechanism for 2a-to-3a dehydrogenation involves a synergistic effect between the two neighboring Co sites over CoSe in both redox process (CoIII/CoII) and Lewis acid-catalyzed procedure.