High-Entropy Effect Breaking the Oxo Wall for Selective High-Valent Metal–Oxo Species Generation

Abstract

The advancement of multiphase catalysts that consist of multiple active sites is the key to improving the catalytic activity of peroxymonosulfate (PMS)-based Fenton catalysts. However, enormous challenges remain in rationally regulating the electronic configuration of each metal center to further improve the PMS activation kinetics. The generation of high-valent metal–oxygen species (e.g., Co (IV)═O and Cu (III)-O) poses as a major obstacle due to the “oxo wall” rule. Herein, we introduce high-entropy engineering, which cleverly and rationally utilizes the high-entropy effect to extract electrons from the d-orbitals of target metals through the asymmetric co-coordination of metal atoms with different electronegativities, thereby promoting the electron delocalization of the target metals. The electronic structure of each site of the high-entropy oxides (HEOs) (ZnMg)(MnCoCu)₂O₄ was further adjusted to promote the activation kinetics of PMS, which facilitates the efficient and sustainable generation of late transition high-valent metal–oxygen species. Both experimental results and theoretical calculations show that the interaction of various metal atoms with different electronegativities reduces the electron density of the Cu and Co sites, and shifts the d-band centers downward, thus optimizing the adsorption energy for PMS activation. Finally, the HEOs catalyst was prepared on the polyester fiber cotton for the flow-through device to achieve continuous and efficient removal of micropollutants (degradation efficiency >90% after 24 h of operation). This work provides new insights into the modulation of the electronic structure of targeted metal centers and the conformational relationships at the atomic level.