Interfacial electronic engineering of carbon nanosphere-confined Ni2P-FeP heterojunctions for water splitting and electro‐Fenton

The water splitting with electro-Fenton (WS-EF) system offers a dual-functional approach for sustainable H 2 production and pollutant degradation, of which the key is to the development of catalysts with high conductivity, multi-active sites, and synergized pathways for hydrogen/oxygen evolution reactions (HER/OER) and EF processes. In this work, we propose a metal-organic framework (MOF)-derived synthesis strategy to construct carbon nanosphere-confined Ni 2 P-FeP heterostructures on nickel foam (Ni 2 P-FeP@C/NF) via in-situ confined growth, carbonization-alloying, and phosphidation strategy. First-principles calculations reveal that the carefully engineered Ni 2 P/FeP interface effectively tubes the metal d-band center, achieving an optimal hydrogen adsorption free energy for HER while precisely regulating *OOH intermediate adsorption for OER. The Ni 2 P-FeP@C/NF exhibits outstanding electrocatalytic performance, achieving low overpotentials of merely 69.5/233 mV for HER/OER, along with a voltage of 1.55 V at a current density of 10 mA cm cm −2 for overall water splitting. When employed in the electro-Fenton system, the heterointerface exhibits multifunctional catalytic properties: it selectively promotes the 2e - oxygen reduction pathway (85 % H 2 O 2 selectivity) and achieves remarkable sulfamethazine degradation (0.28 min −1 kinetic rate, 78 % TOC removal) in the KOH solution. The carbon nanosphere-confined Ni 2 P-FeP heterojunction nanospheres demonstrate exceptional long-term stability for both water electrolysis and electro-Fenton catalysis. This work pioneers interface engineering strategies for coupled hydrogen production-wastewater treatment systems by tuning electronic structure. The interfacial-engineered Ni 2 P-FeP@C heterostructure synergizes carbon confinement and bimetallic interfaces to concurrently drive hydrogen/oxygen evolution reaction for water splitting and electro-Fenton catalysis, enabling integrated hydrogen production and wastewater purification. • Ni 2 P-FeP@C/NF structure exposing abundant active sites allows rapid charge transfer. • Atomic-level Ni 2 P-FeP interface achieves near-ideal adsorption free energies. • Ni 2 P-FeP@C/NF features record-low overpotentials and a breakthrough in OWS voltage. • Heterointerface has ultrafast pollutant degradation (0.28 min −1 , 78 % TOC removal). • High H 2 O 2 selectivity (85 %) in 2e - ORR addresses kinetic mismatch in WS-EF systems.