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

Area of Science:

• Environmental Chemistry
• Materials Science
• Catalysis

Background:

• Peroxymonosulfate-based advanced oxidation processes (PMS-AOPs) are hindered by kinetic limitations in cerium oxide (CeO₂) catalysts.
• Sluggish interfacial electron transfer and inefficient oxygen-containing intermediate desorption impede catalyst performance.

Purpose of the Study:

• To engineer a novel dual-transition-metal (Fe/Co)-doped CeO₂ catalyst to overcome kinetic limitations in PMS-AOPs.
• To optimize the electronic structure of CeO₂ via gradient 4f-2p-3d orbital coupling for enhanced catalytic activity.

Main Methods:

• Self-templating synthesis was employed to create Fe/Co-doped CeO₂ catalysts.
• Comprehensive characterization techniques were used to analyze catalyst structure and electronic properties.
• Density Functional Theory (DFT) calculations were performed to investigate reaction mechanisms and energy barriers.

Main Results:

• Fe/Co co-doping induced lattice distortions, increased Ce (IV) content, and narrowed the energy gap, enhancing interfacial electron transfer.
• The optimized FeCo3-CeO₂ catalyst achieved a norfloxacin degradation rate constant 25-fold higher than Fe-CeO₂ and 7-fold higher than Co-CeO₂.
• Mechanistic studies revealed dual radical/non-radical pathways, with Ce sites generating ¹O₂ and Fe/Co sites initiating SO₄ ^•- formation.

Conclusions:

• The Fe/Co-doped CeO₂ catalyst effectively resolves kinetic bottlenecks in PMS-AOPs by optimizing orbital coupling and intermediate desorption.
• The catalyst exhibits broad applicability, robustness in various water matrices, and sustained high pollutant removal efficiency in continuous-flow operation.
• This study provides a foundation for designing high-performance 4f-material catalysts for water purification through precise orbital coupling regulation.