Renewable biomass conversion into high-value chemicals is essential for sustainability. 5-Hydroxymethylfurfural (HMF) can be converted into 2,5-Furandicarboxylic acid (FDCA) for bio-based polymers. Electrochemical oxidation of HMF is eco-friendly and efficient for hydrogen production. The adsorption of HMF and OH- on catalyst surfaces is crucial, with competitive adsorption challenges. Designing catalysts with a Built-In Electric Field (BEF) to modulate surface charge distribution enhances HMF adsorption. NiO-CuO catalysts show promise due to their structure and selectivity for FDCA production. The NiO-CuO heterostructure with BEF enhances HMF adsorption indirectly by regulating OH- adsorption. Constructed on a 3D substrate, the NiO-CuO catalyst exhibits successful charge redistribution and improved catalytic activity for HMF/HER with high selectivity and Faradaic efficiency. The catalyst requires low voltage for high current density and shows potential for efficient biomass conversion.