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An in-situ electrochemical reconstruction strategy was employed to excite the intrinsic activation of Ni MOF/Ag, which further confirmed that the high-valance Ni3+/Ag+ species are the main active sites for HMF oxidation. Nearly 100% HMF conversion and 98.6% Faradaic efficiency of FDCA have been realized at the optimal potential of 1.623 V vs. RHE. [Display omitted] • In-situ electrochemical reconstitution was proposed for CF-Ni MOF/Ag catalyst. • Catalytic sites for HMF oxidation were determined as NiOOH/Ag+. • The superior elctrocatalytic activation remained after five consecutive cycles. • Paired system exhibit desirable performance for HMF oxidation and 4-NP reduction. Understanding the intrinsic nature of materials is considered as a critical approach to reach the desirable catalytic activity. However, there is still a lack of sufficient research on rational reconstruction of catalyst, especially in the field of 5-hydroxymethylfurfural (HMF) oxidation. This work successfully reconstituted Ni MOF/Ag via surface-electrochemical activation, revealing that Ni3+/Ag+ is the main active species for HMF oxidation. This unique evolution not only acquired high-valence active species, but also stably anchored Ag species to the catalyst surface through the generated NiOOH. Importantly, the initial-potential of activated Ni MOF/Ag for HMF oxidation is much smaller than oxygen evolution reaction (OER), so HMF oxidation is more favorable than OER. Meanwhile, open-circuit potential vs. time experiments well illustrated that Ni3+/Ag+ species exhibited the superior self-healing ability during the conversion of HMF → 2, 5-furandicarboxylic acid (FDCA). Nearly 100% HMF conversion and 98.6% Faraday efficiency of FDCA were obtained at 1.623 V vs. RHE. Therefore, a structure–activity relationship between the reconstructed Ni3+/Ag+ species and HMF oxidation was deeply dissected for efficient production of FDCA. [ABSTRACT FROM AUTHOR]

Electrochemical induced CuOOH/NiOOH active species performs the desirable activity for HMF oxidation. Nearly 100% FE (FDCA) was achieved in the paired-electrocatalytic system. Therefore, this work provides a new perspective for in-depth dissection of the reconstructed species. [Display omitted] • In-situ electrochemical reconstitution was proposed for CuO/Ni-BTC MOF. • Catalytic sites for HMF oxidation were determined as CuOOH/NiOOH species. • Close 100 % HMF conversion and 91.0 % FE FDCA were obtained at 0.55 V vs Ag/AgCl. • Paired electrocatalytic system exhibits superior performance for HMF oxidation. The biomass-derived 5-hydroxymethylfurfural (HMF) oxidation holds great significance for the sustainable production of value-added chemicals. However, the construction of active species with efficient oxidative-activity of alcohol/aldehyde still faces a great challenge. In this work, the reconstruction of CuO/Ni MOF successfully implanted CuOOH/NiOOH and deeply clarified their catalytic mechanism for HMF oxidation. It is worth noting that CuOOH/NiOOH exhibited an excellent self-healing ability during HMF oxidation, further realizing the reproducibility and long-term stability of catalyst. Moreover, a two-chamber electrocatalytic system combining HMF oxidation with 4-nitrophenol hydrogenation was established based on the activated CuO/Ni MOF. As a result, the overall reaction achieved a current density of 47.6 mA/cm2 at 0.55 V vs Ag/AgCl (3.0 h), and the corresponding conversion rate and Faraday efficiency reached nearly 100 %. This study provides new insight into the electrocatalytic-reconstruction strategy to implant active species for alcohol/aldehyde oxidation. [ABSTRACT FROM AUTHOR]