Engineering interface-confined electronic bridge via Mo-S-Fe-O-Mo structure to boost Fenton-like performance for...

The constrained persulfate affinity and sluggish Fe(II)/Fe(III) cycling limit Fe-based Fenton catalysts for in-situ groundwater remediation. Herein, an interface-confined Mo-S-Fe-O-Mo electron bridge was designed and constructed onto the Fe-based catalyst surface, enabling electronic coupling between Fe and Mo sites via O- and S- bridges. The obtained catalyst exhibits outstanding performance in activating peroxymonosulfate (PMS) to degrade diverse organic pollutants with extraordinary utilization efficiency and sustaining long-term stability. The degradation rate of carbamazepine reached to 3.78 min^-1, increasing by 56 times compared with the other systems. Theoretical analyses reveal that the Fe-centered electron bridge enhances the electron delocalization of the bridge Fe site through the lateral pulling effect of the adjacent electronegative Mo sites, thereby facilitating PMS adsorption and subsequent electron transport. Furthermore, the bidirectional Mo-S-Fe-O-Mo bridge accelerates Mo-to-Fe electron transfer, promoting Fe(II)/Fe(III) redox cycling. Consequently, both radical and non-radical oxidation regimes are enhanced, resulting in a much higher and long-lasting pollutants removal capability. After rheological tuning, the catalyst suspension migrates smoothly through porous media and remediate simulated contaminated-aquifer via the Fenton reaction. This work provides guidance for synthesizing Fenton-like catalysts through incorporating structural features, offering a novel promotion strategy for groundwater remediation.