Regulating 4f‐2p‐3d Orbital Coupling in CeO2 via Dual‐Transition Metal Doping for Efficient Peroxymonosulfate Activation

Why It Matters

The breakthrough resolves kinetic bottlenecks in PMS‑AOPs, enabling faster, more reliable water‑purification technologies for industry and municipalities.

Key Takeaways

• FeCo3-CeO2 degrades norfloxacin 0.2539 min⁻¹
• Rate constant 25× higher than Fe‑CeO2
• Dual 4f‑2p‑3d coupling lowers desorption energy
• Enables simultaneous radical and non‑radical pathways
• Sustains >99% removal in 12‑hour flow

Pulse Analysis

Peroxymonosulfate‑based advanced oxidation processes (PMS‑AOPs) have emerged as a promising route for degrading recalcitrant contaminants, yet conventional CeO2 catalysts suffer from sluggish interfacial electron transfer and stubborn intermediate desorption. These kinetic constraints limit scalability, especially in complex water matrices where rapid, complete oxidation is essential. Researchers have therefore turned to electronic‑structure engineering, seeking to manipulate orbital interactions that govern charge mobility and surface reactivity.

In the latest study, a dual‑transition‑metal strategy—simultaneously introducing Fe and Co into the CeO2 lattice—creates a gradient 4f‑2p‑3d coupling unit. This architecture contracts the Fe/Co‑O 3d‑2p energy gap, raises the proportion of Ce(IV) sites, and facilitates electron hopping between Ce 4f orbitals and the dopant 3d states. The resulting FeCo3‑CeO2 catalyst exhibits a norfloxacin degradation rate constant of 0.2539 min⁻¹, a 25‑fold improvement over Fe‑doped CeO2 and a 7‑fold gain versus Co‑doped material. Mechanistic probes reveal that Ce sites preferentially generate singlet oxygen, while Fe/Co sites trigger sulfate radical formation, delivering a synergistic radical‑non‑radical pathway that accelerates pollutant breakdown.

Beyond laboratory metrics, the catalyst’s durability under continuous‑flow operation—maintaining >99% removal across 12 hours and tolerating diverse water chemistries—signals readiness for real‑world deployment. The ability to fine‑tune orbital coupling offers a versatile platform for designing next‑generation 4f‑based catalysts, potentially extending to other advanced oxidation systems and industrial wastewater streams. As regulatory pressure mounts for efficient, low‑energy water treatment, such materials could become cornerstone technologies in municipal and decentralized purification plants.