Enhanced Fenton-like reactions via interface electron reconstruction in low-crystallinity FeCo bimetallic metal-organic frameworks: Bidirectional control of Fe (III) and Co (II) sites.

In this study, the activity and stability of Fenton-like reactions are enhanced by constructing a low-crystallinity FeCo bimetallic metal-organic framework (FeCo-BDC (BDC denotes as terephthalic acid)) through interface electron reconstruction. However, the specific origins and mechanisms of their enhanced activity, particularly in Fenton-like reactions, remains unclear. Systematic analysis revealed that the isomorphic substitution of Co (II) reduces the coordination number and d-electron count at local Fe (III) sites, shifting the d-band centers (-1.59 eV) closer to the Fermi level. Additionally, Co 3d-orbitals can accept electrons, improving the occupation of antibonding orbitals. Notably, Fe (III) and Co (II) sites exhibit a synergistic effect: Fe (III) sites strongly adsorbed the O point of the peroxy bond (lOO), while Co (II) sites efficiently activated O. Within 5 min, FeCo-BDC achieved a 98 % reduction in Rhodamine-B (RhB), surpassing Fe-BDC by a factor of 76 and homogeneous Fenton catalytic systems (Co (II)/peroxymonosulfate (PMS) and Fe (III)/Co (II)/PMS). This work provides a profound understanding of interface electron reconstruction, offering valuable insights into guiding Fenton-like mechanisms.