CeO2 enhancement on self-grown Ni(OH)2 on nickel foam for 5-hydroxymethylfurfural electrooxidation

This study focuses on developing a novel high-performance electrocatalyst to enhance the electrochemical synthesis efficiency of 2,5-furandicarboxylic acid (FDCA) from 5-hydroxymethylfurfural (HMF). The self-grown, binder-free Ni(OH)₂CeO₂ on nickel foam nanosheet catalyst was prepared via a one-step hydrothermal method without additional Ni sources. XRD, HRTEM, and SAED confirmed the Ni(OH)₂ and CeO₂ phases and demonstrated their heterojunction, revealing the flake-like morphology of Ni(OH)₂ and the particulate nature of CeO₂. XPS analysis showed that the introduction of CeO₂ modulates the catalyst electronic environment, shifting the Ni 2p3/2 peak to higher binding energies which favors more Ni³⁺ formation. The Ni(OH)₂CeO₂/NF electrode outperformed Ni(OH)₂/NF in oxidizing HMF. Electrochemical tests demonstrated that at 1.504 V, Ni(OH)₂CeO₂/NF achieved an HMF conversion rate of 98.9 % and FDCA selectivity of 98.8 % with a Faradaic efficiency of 98.4 %, while showing excellent stability. DFT calculations corroborated that CeO₂ optimizes HMF adsorption on the catalyst and lowers the activation energies for all reaction intermediates. This research developed the robust electrocatalyst Ni(OH)₂CeO₂/NF for FDCA production, and also elucidated the indirect reaction mechanism of the catalyst and the catalytic mechanism by which CeO₂ enhances the electrocatalytic oxidation performance of HMF.