Tuning Fe-P covalency via regenerative phosphorus vacancies for efficient aqueous cyclohexanone degradation

Area of Science:

• Materials Science
• Catalysis
• Environmental Chemistry

Background:

• Phosphorus vacancies (P_v) are increasingly recognized as crucial in defect engineering for advanced materials.
• The catalytic roles of P_v in iron phosphide (FeP) catalysts, particularly concerning activity and stability, are not fully understood.

Purpose of the Study:

• To investigate the impact of P_v on the electronic structure and catalytic performance of FeP.
• To develop a P_v-enriched FeP catalyst for efficient degradation of volatile organic compounds (VOCs).

Main Methods:

• Synthesis of P_v-enriched FeP (P_v-FeP) via in-situ phosphidation and NaBH₄ etching.
• Characterization of catalyst properties and electronic structure.
• Density Functional Theory (DFT) calculations to understand P_v effects on PMS activation and adsorption.
• Catalytic performance evaluation for cyclohexanone (CYC) degradation using peroxymonosulfate (PMS).

Main Results:

• P_v introduction modified FeP's electronic structure, weakening Fe-P covalency and improving oxidative resistance.
• The P_v-FeP catalyst exhibited high activity and long-term stability, suppressing surface reconstruction.
• DFT confirmed P_v facilitates PMS activation via O-O bond cleavage, generating reactive oxygen species (•OH and ¹O₂).
• Over 92% CYC degradation was achieved in 30 min under optimal conditions.
• The catalyst demonstrated excellent reusability through reversible lattice oxygen dynamics.

Conclusions:

• P_v engineering is a viable strategy for designing robust and highly active Fe-based catalysts.
• The P_v-FeP catalyst shows significant potential for the efficient removal of refractory VOCs in aqueous environments.
• This work provides fundamental insights into defect engineering for catalytic applications.