D-Band Center Modulation of Carbon-Confined High-Entropy Alloy Nanofibers for Overall Water Splitting

Abstract

The precise optimization of the electronic structure and surface/interface of highentropy alloys is crucial for achieving quantum-scale modulation in the conversion of electrical energy to chemical energy. Herein, we report a Prussian blue analogues (PBAs)-derived tactic to structure nitrogen-doped carbon (NC) encapsulated highentropy alloys (HEAs) nanoparticles imbedded in one-dimensional carbon nanofibers (HEA@NC/CNF) as a high-performance bifunctional electrocatalyst. The electrospinning-assisted in situ synthesis and thermal conversion of high-entropy PBAs enable the formation of uniformly dispersed FeCoNiMnRu alloy nanoparticles wrapped by ultrathin NC shells, effectively suppressing particle agglomeration and structural degradation. Benefiting from multimetallic synergistic effects and NCinduced electronic modulation, the HEA@NC/CNF catalyst exhibits an optimized dband center. As a result, HEA@NC/CNF delivers outstanding hydrogen evolution reaction activity in alkaline media, requiring an overpotential of only 56 mV to achieve a current density of 100 mA cm -2 , along with exceptional long-term stability. It also demonstrates excellent oxygen evolution reaction performance, requiring an overpotential of only 190 mV to achieve a current density of 10 mA cm -2 . Density functional theory calculations and XPS analyses reveal that the combined effects of Mn incorporation and NC encapsulation induce pronounced charge redistribution and shifts of the d-band centers of key active sites. This accelerates reaction kinetics. This work affords a scalable design paradigm for engineering carbon-confined HEAs with tailored electronic structures for high-performance water electrolysis.