posted on 2021-08-25, 08:29authored byWeixue Wang, Yang Liu, Yifan Yue, Huihui Wang, Gong Cheng, Chunyang Gao, Chunlin Chen, Yuejie Ai, Zhe Chen, Xiangke Wang
Developing
iron-based catalysts with superior activity and stability
is a long-term goal for peroxymonosulfate (PMS) activation in advanced
oxidation processes. Combining the confined interlayer growth strategy
with melt infiltration under dry-chemical conditions, we successfully
synthesized ultrathin 2D Fe3O4 nanosheets with
a monolayer thickness of about 1 nm. Atomic force microscopy, CS-corrected
high-resolution transmission electron microscopy, X-ray photoelectron
spectroscopy, X-ray absorption fine structure, etc. jointly revealed
that the 2D Fe3O4 nanosheets possessed special
graphene-like morphology and enriched oxygen vacancies. As highly
efficient AOP catalysts, a series of refractory organic pollutants,
including phenolic compounds, antibiotics, and pharmaceuticals, were
degraded and mineralized effectively via the activation of PMS. On
the basis of radical quenching experiments, electrochemical analysis,
and theory calculations, the radical generation (·OH and SO4·–) and mediated electron
transfer were verified to be key mechanisms in the reaction. The oxygen
vacancy-rich ultrathin 2D Fe3O4 mediated the
electron transfer between pollutions and oxidants, prompted the redox
cycle of Fe3O4, and remarkably lowered the energy
barrier for interfacial charge transfer. This work could generate
2D metal oxides nanosheets with sufficient oxygen vacancies in a large
scale, leading the insight for boosting the activity of iron-based
catalysts.