Lewis Acid−Base Synergy Enables Dual-Site Adsorption for Efficient Oxidation of 5-Hydroxymethylfurfural

Abstract Replacing conventional, energy-intensive, and high-emission thermocatalysis with electrocatalytic oxidation for converting 5-hydroxymethylfurfural (HMF) offers a promising route to biomass valorization. However, practical deployment remains limited by the scarcity of electrocatalysts that simultaneously deliver high activity and long-term stability, largely because weak reactant adsorption hinders achieving both. Herein, we construct an amorphous-crystalline NiCo(OH)x/Ni2P heterostructure by integrating highly defective NiCo(OH)x with Lewis-acidic Ni2P to enable selective electrooxidation of HMF to 2,5-furandicarboxylic acid (FDCA) under alkaline conditions. At 1.40 V vs RHE, NiCo(OH)x/Ni2P supported on nickel foam delivers 98.9% FDCA yield and 98.7% Faraday efficiency. In situ characterizations and theoretical calculations reveal that the strong Lewis acid−base interactions at the NiCo(OH)x/Ni2P interface promote the generation of active Ni3+ species, strengthen adsorption of HMF and OH−, suppress dissolution of Ni3+δ (0 < δ < 1), and thereby enable highly selective HMF oxidation to FDCA. This study provides a simple and effective blueprint for designing highly active, durable electrocatalysts for efficient biomass upgrading.