Atomic Structure Amorphization and Electronic Structure Reconstruction of FeCoNiCrMo x High‐Entropy Alloy Nanoparticles for Highly Efficient Water Oxidation

Abstract The complexity of the multielement interaction in high‐entropy alloys (HEAs) may provide more active sites to adapt different catalytic reaction steps in oxygen evolution reaction (OER). Investigating the correlation between structure and performance of HEAs electrocatalysts is both essential and challenging. In this work, FeCoNiCrMo x HEA nanoparticles are successfully fabricated utilizing a unique nanofabrication method called inert gas condensation. With the increase of high‐valence metal component Mo, the atomic structure amorphization and electronic structure reconstruction are unveiled. According to the X‐ray photoelectron spectroscopy valence spectra, the d‐band center of FeCoNiCrMo x is ascending, and thus enhancing the adsorption energy. Synchrotron pair distribution function analysis reflects the degree of structural disorder and reveals a robust correlation with the intrinsic OER activities of the electrocatalysts. FeCoNiCrMo 1.0 high‐entropy metallic glass nanoparticles exhibit an outstanding OER performance with an ultralow overpotential of 294.5 mV at a high current density of 100 mA cm −2 . This work brings fundamental and practical insights into the modulation mechanism of metal components of HEAs catalysts for developing OER.