The electrochemical oxidation of 5-hydroxymethylfurfural (HMF) to high-valued 2, 5-furandicarboxylic acid (FDCA) represents a sustainable route to petroleum-derived monomers, yet optimized adsorption and interface-regulated indirect oxidation to promote HMF oxidation reaction (HMFOR) remains a critical challenge. A unique Ag2S interfacial structure finely tuning Ag and Ni3S2 surface (named Ni3S2/Ag2S-Ag) is successfully fabricated at the metal-support junction. The unique Ag2S interfacial layer serves as an electronic bridge to facilitate directional electron transfer from Ni3S2 to metallic Ag, thus promoting the activation of Ni sites. The dynamic Ni2+/Ni3+ driven HMFOR in Ni3S2/Ag2S-Ag (indirect oxidation), leading to an industrial-grade current density (549. 7 mA·cm-2) and high FEs (FEHMFOR of 90. 2% and FE4-NPRR of 83. 5% within 266 h regeneration) in the coupled HMFOR and 4-nitrophenol reduction reaction (4-NPRR) system. Techno-economic analysis reveals a net profit of 2, 637/ton HMF converted, with the strong feasibility for large-scale application. In situ Raman spectroscopy confirms the valence-state-mediated indirect oxidation mechanism. Density functional theory calculations and transient electrochemical analysis demonstrate that the metal phase (Ag) significantly optimizes the substrate adsorption. Furthermore, the deactivation reasons and the regeneration methods for Ni3S2/Ag2S-Ag have been explored. The regenerated bifunctional catalyst developed in this study provides a feasible strategy for the large-scale sustainable production of high-value-added chemicals.
Zhao et al. (2026) studied this question.