Utilizing the oxygen-atom trapping effect of Co3O4 with oxygen vacancies to promote chlorite activation for water decontamination

• 成果类型: Article
• 署名作者: Su, Ruidian; Gao, Yixuan; Chen, Long; Chen, Yi; Li, Nan; Liu, Wen; Gao, Baoyu; Li, Qian
• 署名单位: Shandong University; Peking University; Qingdao University of Science & Technology
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-12389
• DOI: 10.1073/pnas.2319427121
• 发表日期: 2024-03-12
• 关键词: rate constants; dioxide; degradation; catalysts; mechanism; insights; kinetics

摘要

Heterogeneous high-valent cobalt-oxo [equivalent to Co(IV)=O] is a widely focused reactive species in oxidant activation; however, the relationship between the catalyst interfacial defects and equivalent to Co(IV)=O formation remains poorly understood. Herein, photoexcited oxygen vacancies (OVs) were introduced into Co3O4 (OV- Co3O4) by a UV-induced modification method to facilitate chlorite (ClOz) activation. Density functional theory calculations indicate that OVs result in low- coordinated Co atom, which can directionally anchor chlorite under the oxygen-atom trapping effect. Chlorite first undergoes homolytic O-Cl cleavage and transfers the dissociated O atom to the low-coordinated Co atom to form reactive equivalent to Co(IV)=O with a higher spin state. The reactive equivalent to Co(IV)=O rapidly extracts one electron from ClO2- to form chlorine dioxide (ClO2), accompanied by the Co atom returning a lower spin state. As a result of the oxygen-atom trapping effect, the OV-Co3O4/chlorite system achieved a 3.5 times higher efficiency of sulfamethoxazole degradation (similar to 0.1331 min(-1)) than the pristine Co3O4/chlorite system. Besides, the refiled OVs can be easily restored by re- exposure to UV light, indicating the sustainability of the oxygen atom trap. The OV-Co3O4 was further fabricated on a polyacrylonitrile membrane for back-end water purification, achieving continuous flow degradation of pollutants with low cobalt leakage. This work presents an enhancement strategy for constructing OV as an oxygen-atom trapping site in heterogeneous advanced oxidation processes and provides insight into modulating the formation of equivalent to Co(IV)=O via defect engineering.