Molybdenum-Enhanced Conductivity and Nickel Electron Density Synergizing With Phosphorus-Induced Oxygen Vacancies in NiMo-Based Heterostructures for Efficient Electrooxidation of 5-Hydroxymethylfurfural.

Abstract

5-Hydroxymethylfurfural (HMF) can be electrocatalytically oxidized to 2,5-furandicarboxylic acid (FDCA) with concurrent hydrogen evolution, providing a sustainable route for biomass valorization and clean energy generation. In this study, we synthesized a three-dimensional nanorod heterostructured catalyst composed of NiMoO4 and NiMoP2 directly on nickel foam (NiMoP@NF) via a one-step hydrothermal method. Mo doping effectively enhanced the material's electrical conductivity and increased the electron cloud density around Ni active sites, while P doping introduced abundant oxygen vacancies and modulated the catalyst's electronic structure, thereby strengthening interfacial electronic coupling and optimizing the adsorption energies of reaction intermediates. Electrochemical testing shows that NiMoP@NF exhibits outstanding HMF oxidation activity: at 1.50 V vs. RHE, HMF conversion approaches 100%, FDCA yield reaches 97%, and the Faradaic efficiency is 96.8%. Mechanistic analysis indicates that the Ni3+/Ni2+ redox couple serves as the active center, while phosphorus doping improves adsorption energies and lowers the activation barrier of the rate-determining step. This work presents a high-performance, non-precious electrocatalyst for biomass upgrading and offers design principles for heterostructured catalysts in integrated energy systems.