Stabilizing Ni3+ Species through High-Valence Molybdenum Introduction for 5-Hydroxymethylfurfural Electrooxidation

5-Hydroxymethylfurfural (HMF) electrooxidation for 2,5-furandicarboxylic acid (FDCA) production has become a sustainable method for value-added products at the anode. Here, an amorphous NiMo composite oxide supported on nickel foam (NF) is fabricated for HMF electrooxidation (HMFOR) via one-step electrodeposition. The synthesized NiMo/NF delivers 98.3% FE toward FDCA at 1.5 VRHE and maintains FE above 90% during 10 h. In situ Raman spectroscopy proves the formation of the active species Ni3+-OOH during the reaction process. Due to the introduction of high-valent Mo6+, the Ni3+ active species can be stabilized and the adsorption of aldehyde in HMF can be promoted during the reaction process, thus enhancing the FDCA electrosynthesis performance.