Structure-Oriented Electrochemical Synthesis of Layered Double Hydroxide Electrocatalytic Materials for 5-Hydroxymethylfurfural Oxidation

Quantitative conversion of biomass-derived 5-hydroxymethylfurfural (HMF) to downstream chemicals at room temperature is a critical milestone in sustainable chemistry. Herein, conversion of metal-organic framework (MOF) structures into layered double hydroxide (LDH) electrocatalytic materials (NiFe-LDH/MOF) was fabricated using NiFe-MOF as a structure-oriented sacrificial template via an in situ electrochemical strategy. Results showed that the electrochemical method to convert the material structures not only overcame inherent limitations of MOF structures (inaccessible sites and low conductivity) but also eliminated LDH self-stacking. Hierarchical NiFe-LDH/MOF exhibited high catalytic activity and selectivity in the electrooxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA), which is due to the increased number of catalytically active sites and the extended electron transport channels of uniformly dispersed LDH nanosheets. Optimized Ni2Fe1-LDH/MOF materials achieved FDCA yields of 99% with Faraday efficiencies of 99% in 1 M KOH with 50 mM HMF at an applied potential of 1.40 V vs reversible hydrogen electrode at ambient temperature. This work demonstrates a promising method for fabricating LDH electrocatalytic materials from MOF structures and shows a proof of principle for selective oxidation of HMF to FDCA.